THE RADIO BUILDER

Various schematics with Russian Transistors, Regen, Reflex, Direct Conversion, Superhet Designs

2012-10-30T20:50:00.000-07:00

For equivalents of Russian transistors refer to this post.

MW_Regen_1V_One Triode Pentode Tube_8JV8

2012-10-30T20:36:00.000-07:00

Signals from the antenna (a 2-meter piece of wire) are fed to the input tank via C3. Antenna coil LA was wound on a piece of 19mm diameter plastic tubing (in this case it came from a junked clothes hanger). There's a tap at 25 turns from the cold end.

The triode section works as a regenerative detector, being biased by C6 and R8. It's grid and cathode share the same DC voltage and regeneration is controlled by varying the plate voltage. Detected audio, taken from the plate, is first run through the low pass filter R4 and C4 and then fed to the pentode's grid. The pentode part is biased by C8 and R9. R6 and C7 provide power to the second grid. Finally, T1 matches the low impedance of the small speaker to the fairly high output impedance of the tube. For simplicity's sake there is no volume control or power switch.

Source: http://coolshop.dnsalias.org/projects/1tuberegen/1tregenrx.html

MW_Superhet_1V_6ME8_Beam deflection tube

2012-10-30T20:29:00.001-07:00

the local oscillator runs 455kHz above the RF. The center tapped audio detector transformer is replaced with a custom built IF transformer and filter. The audio output transformer of the direct conversion set is replaced with the 2nd IF transformer. The detector is now a 1N34A diode, and the detected audio is reflexed once again back through the tube with the audio finding it way to the final audio output transformer. Another difference, is that in order to collect the three separate signals (RF, IF and AF) to feed into grid 1, I'm using a tertiary winding on the RF coil T1. Also, there is a clear DC path from the detector diode all the way back to grid 1, which will provide AGC voltage.

Source: http://www.dutchforce.com/~eforum/index.php?showtopic=22262&st=0&

MW_Direct Conversion_1V_Pentode tube 6ME8_Beam deflection tube

2012-10-30T20:24:00.000-07:00

Well, It is kind of shift to the valves or tubes. It is really amazing how those glowing glassy things can amplify and turn receivers and transmitters on!
I know some people may say that transistor are or fascinating but I kind of thinking the other way. How could you think that simple addition of (grid and anode) to the bulb can make a triode out of it?!
Therefore, I will post some ingenious valve circuits involving regeneration, superhet and direct conversion methods. Specially the ones that have low number of valves for they look more interesting and brainy.
How much you can make out of one valve?!
Well, some valves are actually two valve in one spot like one triode and pentode packed in one glass.

Here, I selected for you a brainy project about direct conversion receiver made of one valve (tube).

Beam deflection tubes were designed to be used as balanced mixers. The most interesting feature is that any signal applied to grid 1 will be amplified and appear as an in-phase (common mode) signal at the two plates. On the other hand, any signal applied between the deflector plates will be amplified and appear as an out of phase (differential mode) signal at the two plates. This allows the different signals to be separated and redirected as necessary. This unique characteristic allows reflexing the audio back through the tube without it breaking into oscillation.

To work as a direct conversion receiver, the RF signal passes through a tuned RF stage consisting of T1 and one section of the tuning capacitor, and is applied to grid 1. A signal from the local oscillator (an interesting differential oscillator design) running at the same RF frequency is applied to the deflectors. The result of this mixing operation is an out of phase audio signal at the plates. The out of phase audio is detected in T3 and from the secondary is routed back to grid 1. This audio signal is amplified and appears at the plates as an in-phase signal which passes through the primary of T3, this time with no effect, and then to T4 where it is impedance matched to the headphones. Some cathode current is routed through a single turn winding on T1 for regeneration which is adjusted by the parallel 50 ohm pot. Because the regen is taken from the cathode, there is no local oscillator component in this signal. After the usual amount of debugging and tweaking, this thing ended up being an amazingly sensitive and selective receiver. I was able to pick up stations up to 2200km away quite clearly. Not bad for one tube.

Source:
http://www.dutchforce.com/~eforum/index.php?showtopic=22262&st=0&

Voltage doubler tripler quadrupler

2012-10-14T19:20:00.000-07:00

Source: http://www.coolcircuit.com/circuit/voltage/ Voltage Doubler
This is a simple voltage doubler circuit which has the output voltage is 2xVin Volatge Doubler The above circuit is cascade type voltage doubler circuit. Note : both type of the above voltage doubler circuit must have rated voltage of capacitor and diode greater than 2 times of Vin. Voltage Tripler This circuit will give the output voltage 3 times of input voltage. The rated voltage of all capacitors and diodes must be greater than 2 times of Vin. Voltage Quadrupler The above circuit is a voltage quadrupler circuit which have the output voltage is 4 times of Vin.The rated voltage for all capacitor and diode must be ggreater than 2 times of Vin.

Halloween Speaking Pumpkin using Arduino chip

2012-10-13T19:32:00.000-07:00

Halloween pumpkin
Source: http://www.ladyada.net/make/pumpkin/pumpkin.html

This is a modified version of the project that is a little 'accellerated' for easy videoing

Here is a quick project for an electronic halloween pumpkin. With a bit of hacking a $1 plastic pumpkin is upgraded: a sensor embedded in the nose detects when people get close and will play scarey sounds and animates LEDs on the face. The sounds are stored on an SD card so its easy to change and customize what the pumpkin says, while the code is written for an Arduino so its easy to modify the behavior. I'm going to have this pumpkin outside my door to freak out the little kids who go to daycare nearby. Boo!

What you will need

Arduino - $34
Wave Shield + any size SD card - $27
Small (approx 3") 8 ohm speaker, can be recycled from a broken gadget - $4
Distance sensor - Sonar Maxbotics EZ1 is suggested - $25
A bunch of diffused red or orange LEDs + resistors - $1
Hollow plastic pumpkin (or other) + plastic bowl - $2
Wire - 22 gauge or ribbon cable is fine - $1
Various tools, adhesives, etc.

This isn't a particularly tough project, but you'll need to know basic Arduino/Microcontroller programming and soldering

Here is the sketch that does it all!

Sound effects

There are tons of CDs and mp3 packages available for purchase that contain a large assortment of sounds. Here are some free download sites that you can scour:

Here is my collection (in a zip file) of converted sounds: they're ready to go and have been tweaked to improve the sound where possible

Step 1: Playing sounds through the speaker

Assemble the Wave Shield kit and get your Arduino board up & running. Copy the zip of example halloween wave's onto the SD card and run the DAP example sketch. Each sound should play in sequence. Look at the debug log if there are any issues.

Next, solder two wires to the speaker and connect them to the shield as shown, you should be able to hear the effects pretty well
If you want a power boost, you can 'piggyback' another amplifier chip (TS922) on top of the existing one. This will approximately double the maximum volume

Step 2: Choose and connect sensor

Next, we will connect up a distance sensor. There are two basic 'flavors' of distance sensing: infrared and sonar. IR works better for close range (about a meter or more) and sonar works better for longer ranges (up to 10 meters)

Sonar and IR sensors

Since I want this pumpkin to activate from a few meters away, I'm going with a sonar sensor. The nicest one I've seen so far is the Maxbotics EZ1 which has both digital and analog signal outputs, runs from a range of voltages and can detect more than 6 meters away. If you're using a different sonar, the code may be different so you will have to first get that device working and then come back once you have functional interface code

The maxbotix is easy to use. Connect three wires: Power, Ground and Analog signal as shown.

Finally connect the sonar to the shield so that the analog signal feeds into Analog In #0 and the power and ground wires are connected to power and ground.

Load up the sketch above into the Arduino. Note the following chunks of code.

In this bit we read 8 seperate measurements from the sonar and average them. This avoids one or two oddball readings:

void loop() { 
...
   distsensor = 0;
   for (i=0; i<8 8="8" analogread="analogread" codefragment="codefragment" delay="delay" distsensor="distsensor" ensor="); Serial.println(distsensor);
...</pre>
      </blockquote>
    </div>

    <p>After that we have some 'repeating' if-then statements. Here, we 
see how large the reading was. A reading of 500 indicates more than 6 
meters away and in that case we will pick a random number between 0 and 
199 and if its 0 (1/200 times) then we'll play one of three scary sounds</p>
    <div class=" i="i" putstring_nl="putstring_nl">
      
        ...
     if (distsensor > 500) {
     ...
     pumpkinstate = 1;
     // nobody there. one out of 200 times play one of the scary sounds (once every few minutes)
     i = random(200);
     if (i == 0) {
       i = random(3);
       if (i == 0) {
           playcomplete("CACKLE.WAV");
       } else if (i == 1) {
           playcomplete("GOSTMOAN.WAV");
       } else {
           playcomplete("CATSCREM.WAV");   
       }
     }
...

The 'pumpkinstate' variable is used to keep track of how far the target was last we checked. This will let us know if they are getting closer or farther away over time.
Next get yourself one of those $1 plastic pumpkins from your local drug store.

They are hollow, making them perfect for stashing electronic wiring!

Cut a hole in the nose so that the sonar can be press-fit in

Set up the sonar so that it is pointing at a large open space (the readings are consistantly over 500) Then experiment with walking near and around it. Adjust the randomness if you want to make it more or less noisy. You can also change what audio files get played when.

Step 3. Adding LEDs

Its not a real electronics project without some blinky LEDs! Lets add some LEDs for the pumpkins eyes and mouth.

Punch 5mm holes in the eyes and mouth. In this case I'm using 2 for the eyes and 5 for the mouth.

Next heat up a hot glue gun and secure the LEDs so they dont slip out. In general I dont suggest hot glue for -anything- but in this case its OK.

Next its time to wire up the LEDs. I'm going to control the eye LEDs at once and divide the mouth into three symmetric sections so that I can do some simple animations with the mouth. Since red LEDs have a voltage of about 2 volts and the Arduino runs at 5V, I can stack two at a time to simplify wiring:

The LEDs are controlled from the analog in pin that aren't used - don't forget that they can also be used as digital input or outputs! The 2 eyes are connected to analog pin #4, the two outer mouth LEDs to analog #5, the middle-outer mouth LEDs to #2 and the one remaining LED from the center goes to analog #3. (It doesn't particularly matter which pins go to which LEDs, just that this ended up being what I did)

I used some leftover ribbon cable to do the wiring. Watch that you don't burn your fingers or the pumpkin!

If you have a handy 5v power supply kicking around, you can test the LEDs - I used my benchtop supply

Step 4. Wiring up the lights

Finally connect the LEDs to the Arduino as indicated in the schematic

The plan is to make the pumpkin's mouth animate with the sound. Although we could do this all in 'software' it turns out to be a heck of a lot easier to just use an analog input to measure the output of the amplifier. So connect a wire from the 1.5K resistor back to analog input #1

Now lets make some blinky! There is code in the sketch that will turn on the eye LEDs when someone gets near:

...
   if (distsensor <= 500) {
     digitalWrite(eyeleds, HIGH); 
   } 
   if (distsensor > 500) {
     digitalWrite(eyeleds, LOW);  
...

And then in the wave playing code, we will animate the pumpkin. First we take a few readings from the analog sensor. The audio signal is centered around 2.5 (ranges from 0 to 5) so we subtract 512 (half of the maximum analog read value) and then invert it if it is negative. This gives the 'absolute value' volume. Then we take the maximum value of 8 reads. Then depending on how loud it is we light up the mouth. You can mess with the values a bit if you want to have a different effect.

...
while (wave.isplaying) {
   volume = 0;
   for (i=0; i<8 br="br" i="i">     v2 = analogRead(1) - 512;
     if (v2 < 0) 
        v2 *= -1;
     if (v2 > volume)
       volume = v2;
     delay(5);
   }
   if (volume > 200) {
     digitalWrite(outermouthleds, HIGH);
   } else {
     digitalWrite(outermouthleds, LOW);
   }
   if (volume > 150) {
     digitalWrite(midmouthleds, HIGH);
   } else {
     digitalWrite(midmouthleds, LOW);
   } 
   if (volume > 100) {
     digitalWrite(mouthleds, HIGH);
   } else {
     digitalWrite(mouthleds, LOW);
   } 
   //putstring("vol = "); Serial.println(volume, DEC);
  }
...

I wrote a version of the sketch that is a little 'accellerated' for easy videoing. But basically it will look and act just like this

Step 5. Finishing up

Time to wrap up the project. You'll have to decide how to power the pumpkin. If you want to have it be fully contained you can use a battery pack. Either make one from 4 AA batteries or use a Mintyboost kit. Basically you'll want about 4.5-6V

Or you can cut a small hole in the back of the pumpkin and use a 9-12V DC adapter.

Finally, use a plastic bowl (preferrably orange, all I had in the kitchen was a blue one!) and put some candy in there! (Like leftover altoids gum)

Happy halloween!

Toy's mouth motion by servo

2012-10-13T19:16:00.003-07:00

Build Your Own Mouth Animation

Monstrous creatures are more convincing if they do something, like move or talk. Talking monsters make your haunt a graveyard smash, but how do you do it? In 2002, it became difficult to find pre-assembled talking gadgets that could be modified for Halloween use. Suddenly, it became more practical - and important - to be able to build your own from scratch.
This page surveys ways to build your own device that takes an audio stream and moves a mouth mechanism to match.

RC Servos
- Ray Martin servo
- Scary Terry servo
- Wale and Noon servo
- Derek Verner servo
Solenoids
- Noon solenoid
DC Motors
- Jim Kadel toy servo
Related Pages

RC Servos

Using RC servo for animated creature mouths...

Ray Martin servo

Ray Martin is a friend of ours who designs toys for a living, sometimes electronic, sometimes mechanical. We were having lunch after the TRW Amateur Radio Club swap meet, and I mentioned that some of the best hackable products with animated mouths were discontinued, and Halloween lovers were constructing alternatives out of things like servos. Ray said, "I have a circuit that does exactly what you need on my desk right now!" Ray went further than that. He customized it for specific servo limits and pulse frequency, built and tested it, and sent it to me.
Click for full size schematic.

We have a page dedicated to details of Ray's Sound-To-Servo Driver.

Scary Terry servo

I believe that Scary Terry is the grandfather of made-from-scratch talking creatures. When he noticed that Douglas Fir and other hackable animated figures were disappearing from the stores, Terry forged ahead and built his own. Terry's design uses a RC servo embedded in a plastic skull.

Click for full size schematic. This is rev 3.1 of his design, dated 8/20/2002.

For more hauntingly clever ideas, visit Scary Terry's web site at http://www.scary-terry.com

Wale and Noon servo

The November 2002 (Vol 23, no 11) issue of Nuts and Volts contains an article by John Wale and Walt Noon (pg 72-76). The article describes an animated Christmas train that carries talking gift boxes. The talking boxes use a RC servo for the mouth motion.
Click for full size schematic.
The transformer is 8-ohm to 1K. Presumably the 8-ohm side goes to the audio input, and the 1K side goes to the transistor that controls the 555 timer.

Derek Verner servo

Wolfstone reader Derek Verner wrote in July 2005 to describe his sound-to-servo solution. Here's how Derek described it:

Velleman makes a four servo controller that uses as its inputs voltages from zero to five volts. ... I use speaker level output from the recorders to drive small lamps that form part of opto-isolators. The other halves are CDS photocells. Each CDS cell is fed to an input of the controller in series with a trimmer pot. Across the pot (from one end to the wiper) is a voltage of six volts. When the recorded sound output is higher the lamp glows brighter and a higher voltage is fed to the controller. One need only vary the volume of the sound while recording to control the servo position.

Actually, there's a typo in there. Derek meant DIY Electronics, Kit 102 - Servo Motor Driver.

Solenoids

Using solenoids for animated creature mouths...

Noon solenoid

The September 2002 issue of Nuts and Volts contains an article by Walt Noon (pg 46) describing some of his haunt props, a pneumatic popup and a talking seagull. Included was a schematic for a mouth circuit that uses a solenoid to actuate the jaw. Click for full size schematic.

Walt offers more information at his web site at http://www.noonco.com/ghoul/dc.htm

DC Motors

Using electric motors for animated creature mouths...

Jim Kadel toy servo

Jim Kadel, who runs Haunt Master Products, Inc. also has a web site for his home haunt, where he generously provides technical information on some of his noncommercial projects. For Halloween 2003, Jim presented a schematic to retrofit talking props that use small DC motors as servos.
Click for full size schematic.

For more information, please visit Jim's web site at http://home.rica.net/jimk/projects/servo/index.htm

The Funny Mouse Toy_based on 555 IC

2012-10-13T19:09:00.000-07:00

By kariloy
@ July 19, 2012

Zooms around searching for light

Cost to build:

$10

Time to build:

12 hours

URL to more information:

http://letsmakerobots.com/node/33474

Weight:

142 grams

Actuators / output devices: 2 small DC motors
Power source: 9v battery
Sensors / input devices: infrared led emitters
Target environment: indoors

My iteration at building the famous MouseBot, originally (Mousey, the Junkbot?) created by Randy Sargent.
I present to you YUMBBBBMH (Yet Un-named Mouse Bot Being Built By My Hands) previously known as MouseBot Still To Be Named and now A.K.A GhostRoachMouseBullRam CrazyBot.
(...or perhaps just GRMBR CB for short? :P)
October, 11th 2012
So after the tip from birdmun regarding what was on the LM386 datasheet application notes regarding gain, I decided to do some tests with capacitors. At first, seemingly I had not much success, but then again my 9V batteries were low on juice and I got lazy and did not recharged them at the time. Last night finally I've put on charging over night, and today decided to fiddle with the mouse bot again. After, making certain everything was connected, the mouse bot lost it's previously typical crazy spin... and instead turned into a crazy shooting arrow. Problem: It crashed so hard against stuff that pop goes the tiny whiskers. So after some brainstorming with ossipee I went looking for a wire cloth hanger... and a couple of pliers and a few (considerable) twists later I got myself a couple of cross sturdy whiskers and mounted them on some holes on the microswitchers (after so filling so they would fit). For enhanced (animal) security at the end of each whisker I've deposited a blob/ball of hot glue. Turn it on, and success, now it zooms around like an enraged brutish mouse, without the whiskers falling off. I now consider this project, my second robot project, first to be fully completed. So, MAJOR the trick is to connect pins 1 and 8 of the LM386 through a CAPACITOR and not directly (see altered schematic bellow), otherwise you might end up with a spinner.

September 9th, 2012
So, I've tracked the uneven voltage problem, basically pin 1 and 8 on the LM386 were tied together to provide maximum gain, by cutting that connection I was able to leverage the voltages, however I've lost noticeable gain. Solution: Connect pins 1 and 8 through a resistor. My experiments told me that I needed high (>1 kohms) resistor values to even out the voltage differences, however whenever I increase the resistance I also decreased the sensitivity hence this is going to take some fine tuning later on.
So the schematic should be something like (WRONG...):

the value of the resistor (range of potentiometer) will depend on the LEDs used for optical sensors. I found that normal LEDs and LDRs were unsuited for the task, the best results I got were with IR LEDs.

August 26th, 2012
Since my mousebot CCCW (crazy-counter clockwise) spinner I decided to dig it up again and run a bit more of diagnostics.
I've already measured that the voltages where un-evenly divided between both motors (even when the led "eyes" were blinded -- made a couple of little black hoods for them).
So, I've decided for a "clean" read. Opened the bot up, disconnected the motors and connected the mainboard with the battery. With the switch turned ON I read:
RIGHT motor vcc PIN: ~5V
LEFT motor vcc PIN: (-)3.4V
Turning the trimpot either way change this readout very little. Previous measures directly done on the motor leads while running also shown me that adjusting the trimpot would either raise or lower the voltages but on BOTH motors at the SAME time.

So my guess, is that I inserted the trimpot in the wrong (INDEED WRONG, IGNORE BELLOW) place/way, but I have no idea why or how to fix it. See schema below.

P.S. - See original (from the internet) schema near the end of this post.
July 21th, 2012
It's a few minutes past midnight and finally the still un-named mouse bot made it's first run. Actually it didn't went anywhere given that a wheel popped of after a second or two. And there's low traction. I'm now going to work on securing the wheels better to the motor pinions. Below you can see the final stages of the assembly!

July 20th, 2012
------------------------

After a busy "night-ful" I got most of the base work done:
- Mouse entrails completely removed and made way for new "guts"
-- base (side holes for motors, padding for motors, front holes and mounting of bumper switches)
-- top (on/off switch mounted)
- Perf-board soldered all the components on a small stretch of perf-board
TODO:
- Apply proper connectors to dangling leads;
- Connect everything and test; if(notWorkingProperly){curse(HIGH);}
- Mount/attach the motors and respective wheels
- Close everything up, cross fingers & hope for the best
July 19th, 2012
----------------------
Got a suitable candidate PS/2 mouse to use as a carcass.

July 18th, 2012
----------------------Breadboarded it successfully according to the schematic as show at MAKE magazine of the first mouse bot just added another bump switch and a 100k trimpot:
[Colorful] Schematic:

Breadboard look (before trimpot):

HALLOWEEN SCARE TOY that records and plays sound automaticly

2012-10-13T18:50:00.003-07:00

Halloween Scare using 12F683 and ISD2532
author: Rui Cabral - rui.j.cabralgooglemail.com - www.ruijc.webnode.com

Introduction

Halloween is coming up and it's time to do some pranks.

Everyone likes Halloween and I'm no exception. Every year me and my wife decorate the house with lot's of bugs, spider webs, creepy posters and of course lot's of Halloween candy.

While making the normal Halloween preparations I came up with the idea of making a circuit that would make some scary noises and also would react to movement.

I expect to get some screams and laughs from friends that come to visit us this year.

The circuit is basically a sound chip that records and stores sounds in memory and plays them back with a microcontroller and it's triggered by light and motion.

The sound chip is from maker winbond and has a very good sound quality.

Schematic

Parts List

R1                   10K ohms resistor
R2                   1K ohms resistor
R3                   100K ohms resistor
R4                   5K1 ohms resistor
R5                   470K ohms resistor
R6                   10K ohms resistor
R7                   10K ohms resistor
R8                   1K ohms resistor
LDR                Light dependent resistor
C1                   100nF capacitor
C2                   100nF capacitor
C3                   100nF capacitor
C4                   100nF capacitor
C5                   10uF capacitor
C6                   22uF capacitor
C7                   220uF capacitor
C8                   4.7uF capacitor
SENSOR        GP2D12 from Sharp
IC1                  12F683 microcontroller from Microchip
IC2                  ISD 2532 from winbond
S1                    Push button
SP                    Speaker
MIC                Electret microphone

Others:
Box
PCB
Jumpers
4.8V Battery Pack
Hex program for the microcontroller

PCB

The PCB used for this Project is double layer and its size is 80.66 mm x 47.70 mm.

Top Side

Here is the top side

Bottom Side

Here's the bottom side.

How it works:

This circuit has 2 sensors. One motion sensor ( Sharp GP2D12 ) and a light sensor ( LDR ). The microcontroller monitors both sensors and triggers the sound chip in certain conditions.

Every time the circuit is powered on, the microcontroller stores the distance read by the sharp sensor and uses this as reference for the space available for object/people detection. Anything moving in front of the sensor up to that reference activates the first stored sound.

The other 3 sounds are time triggered only when the light is out. The LDR senses the light intensity and only when placed in darkness it will activate the remaining sounds. Sometimes the sounds are individually played and sometimes combined. There are 4 sounds slots available with max. length of 6 seconds each.

How to record sounds:

The PCB has some connectors with jumpers making it possible to change from record to playback mode and vice versa.

Connector #1 named REC/PLAY is a 3 pin connector and jumper connection must be placed to the left side for record mode or to the right side for playback mode.

Also connector #2 named Jumpers must have 2 jumpers installed for playback mode. This is responsible for the memory address of the sounds.

When in record mode, some wire jumper connections must be made to change the address of the recordings manually connecting pin 2 and 3 to VDD or VSS according to table bellow:

For VDD and VSS connections it's possible to use connector named + -

Recording: With power off, connect a microphone, move jumper to record mode and connect message pin 2 and pin 3 to VSS.

Turn on the power and prepare the sound you wish to record for #1 sound.
Press and keep the S1 push button while recording. Release the button to stop recording.
Connect pin 2 to VDD and keep pin 3 to VSS - this will address sound #2.
Press and keep the S1 push button while recording. Release the button to stop recording.
Connect pin 2 to VSS and pin 3 to VDD - this will address sound #3.
Press and keep the S1 push button while recording. Release the button to stop recording.
Connect pin 2 to VDD and keep pin 3 to VDD - this will address sound #4.
Press and keep the S1 push button while recording. Release the button to stop recording.
Turn the power off, disconnect microphone, restore address jumpers and move jumper to playback mode.

Hex Program

The Hex program named HSCARE.HEX must be saved in the 12F683 microcontroller's memory before soldering on the PCB.

Assembly and testing

After soldering all components on the PCB and once all sounds are recorded it's time to get it inside a box. I've found the perfect box for this project... this skull.

Placing the motion sensor in the eye section.

The sharp sensor adds a crazy eyes look to this skull.

The skull is ready to make some noise and scare the visitors.

Conclusion

This is a very cool Halloween project. It's possible to record personalized sounds making this even more interesting. I bet that this project will bring many screams and laughs.

Downloads

Download this project in .DOC format

MW Regen Reflex_2T_ The two transistor speaker no transformer radio

2012-10-10T22:12:00.002-07:00

This is the simplest Regenerative (Regen) Reflexive (Reflex) radio ever.
The simplest two transistor radio that is capable of driving a speaker.
You may know about the one transistor capable of driving a speaker but the difference here is the voltage. The one transistor radio needed high voltage to function and transformer to have 180 degree phase shift.
No diode used to detect the audio.
Also, no capacitor is used to control the regen but a 1k variable resistor.
On the other hand the LC circuit is easy to be changed to receive other bands like the short wave.

I will leave it for your experiments to check but send me feedback here ...

Airband_3T_IC_BF199_BC547_LM386

2012-10-10T21:52:00.001-07:00

The antenna is connected to a tuning and band pass filter at the same time (wave trap).
Two high frequency transistors BF199 amplify the RF.
One diode detect the audio AA119 (Schotcky diode).
BC547 and LM386 is an audio amplifier.
The circuit is regarded as TRF

CB Receiver_3IC_Superhet_TCA440_1T

2012-10-08T23:10:00.000-07:00

This is a Superheterodyne CB radio based on TCA440. The varicap diode BB304 works with L1 as an IF stage. The two diodes AA119 detect the signal and send it to the opamp. Final output stage to drive the speaker.
----------------

RCA Victor 8x541 schematic and trouble shouting

2012-10-08T22:35:00.000-07:00

Bringing life to valve radio (RCA Victor 8x541)

The antique valve radios suffer from aging. If you like this kind of devices and want to bring them to life, here is a simple procedure to trouble shout.

1. Check the power cable for any damage before plugging it.
2. Turn the radio on.
3. Did all the valves glow?! No = One or more of the valves are burnt out and need replacement.
4. Yes all valves are glowing and after that you here nothing but humming. This means the filter capacitors needs replacement.

I bought RCA Victor 8x541.
I turned it on and got nothing but strong humming and it kind of pick a station.
No cover = this means there is no loop antenna for the LC tank circuit.

I replaced the burnt light bulb with a 16Watts 12V because this is equivalent to the 4Watts 6V ... right?!

I replaced the power source big capacitor with two 47uf 160v capacitors. This terminated the humming totally.
Here is two schematics of five valves superheterodyne receivers. I looked at those schematics and found that this receiver is not much different. I simply couldn't find the free official schematic of this Victor 8x541.

Clearly this very double capacitor of 30uf 50uf 160V is doing the job of filtering the humming in the final output and all the stages before.It is #15 in the schematic above.

After that I connected the classical ~260uH coil discarding its low number of turns parts to replace the loop antenna. It worked good but not really sensitive. I decided to boost the reception by adding an antenna wire. I rapped the wire round the power cable to pick the signal from the power cable. I put 1nf capacitor between the antenna wire and the radio to do two jobs. First to filter the high voltage of the radio from the antenna and to filter the AC humming signal noise from the LC tank. I mean this 1nf capacitor will work as high pass filter. Check the schematic above for the loop antenna in #20. If you connect direct wire to the loop to make an antenna you are actually connected to -B. It should be the neutral of the AC but what if you connected the AC mains in an inverted way?!!

Be careful when dealing with those valve radios for they are mainly ALL not protecting you from electric shock for innocent antenna wire!! But with this 1nF capacitor you can largely screen the AC voltage. Nevertheless, It will give light sting of electricity instead. I noticed very strong and clear reception if you connect the same wire to an EARTH like water pipe at home. This will work a wave trap or an injection of the AM signal by picking it from the AC mains wire and sending it ground and injecting some of it to the LC tank circuit through the 1nF capacitor.
Check the video above and look at the green wire.
The double capacitor that I mentioned earlier is not mistaken for being yellow big one with three wires (black, red, blue).

I noticed not much written online on how to fix those lovely antique radios. A friend of mine just bought an older valve radio than this about 1948 one. I promise to report it here on this blog if I fixed it. Thank you for reading.

Source: http://atheelelectronics.blogspot.com/2012/10/bringing-life-to-valve-radio-rca-victor.html

Bandpass filter using Opamp

2012-10-08T12:32:00.000-07:00

Single Op-Amp Bandpass Filter

A bandpass filter passes a range of frequencies while rejecting frequencies outside the upper and lower limits of the passband. The range of frequencies to be passed is called the passband and extends from a point below the center frequency to a point above the center frequency where the output voltage falls about 70% of the output voltage at the center frequency. These two points are not equally spaced above and below the center frequency but will look equally spaced if plotted on a log graph. The percentage change from the lower point to the center will be the same as from the center to the upper, but not the absolute amount. This is similar to a musical keyboard where each key is separated from the next by the same percentage change in frequency, but not the absolute amount. The filter bandwidth (BW) is the difference between the upper and lower passband frequencies. A formula relating the upper, lower, and center frequencies of the passband is:
Center Frequency = Square Root of (Lower Frequency * Upper Frequency)
The quality factor, or Q of the filter is a measure of the distance between the upper and lower frequency points and is defined as (Center Frequency / BW) so that as the passband gets narrower around the same center frequency, the Q factor becomes higher. The quality factor represents the sharpness of the filter, or rate that the amplitude falls as the input frequency moves away from the center frequency during the first octave. As the frequency gets more than one octave away from center frequency the rollof approaches 6 dB per octave regardless of Q value. Approximate rolloff rates for different Q values for a single octave change from center frequency are:
Q = 1 = 6 dB
Q = 5 = 18 dB
Q = 10 = 24 dB
Q = 50 = 40 dB
For a single op-amp bandpass filter with both capacitors the same value, the Q factor must be greater than the square root of half the gain, so that a gain of 98 would require a Q factor of 7 or more.
The example below shows a 1700 Hz bandpass filter with a Q of 8 and a gain of 65 at center frequency (1700 Hz). Resistor values for the filter can be worked out using the three formulas below. Both capacitor values need to be the same for the formulas to work and are chosen to be 0.01uF which is a common value usable at audio frequencies. This same filter is used in the "Whistle On / Whistle Off" relay toggle circuit.
R1 = Q / (G*C*2*Pi*F) = 8/(65 * .00000001 * 6.28 * 1700) = 1152 or 1.1K
R2 = Q / ((2*Q^2)-G)*C*2*Pi*F) = 8/((128-65) * .00000001 * 6.28 * 1700) = 1189 or 1.2K
R3 = (2*Q) / (C*2*Pi*F) = 16 / (.00000001 * 6.28 * 1700) = 150K

Source: http://www.bowdenshobbycircuits.info/opamp.htm#bandpass.gif

MW loop antenna

2012-10-08T12:28:00.000-07:00

This loop antenna can be used as the LC circuit of Crystal Radio or Regen radio.
----------------------

Loop Antenna for AM Radio

A loop antenna can greatly improve medium wave reception. Loop antennas
are directional and receive signals along the plane of the windings. The
directional quality improves signal to noise ratio of the desired signal
while rejecting signals perpendular to the plane of the windings. Larger
loops are better than smaller ones but good results can be obtained
from moderate sizes of one or two feet on a side. The shape doesn't
make much difference so the loop can be circular, rectangular or
a triangle shape. The main idea is to cover as much area as possible,
so I would imagine a circular loop would be the best. The loop pictured
here measures 15 inches on a side and is about 1.5 inches wide. It was
wound with 16 turns of #35 copper wire, and has a Q of about 100 at
600 KHz. Larger guage wire might have been better (less resistance)
and therefore higher Q and selectivity, but the arrangment here works
pretty well with a bandwidth of about 6Khz at 600Khz. The loop is tuned
with a 30-365 pF capacitor and covers the standard broadcast band of
550-1700 KHz. The antenna signal is inductively coupled to the radio's
internal ferrite rod antenna so no wire connections are needed.
Simply place the radio near the loop antenna and adjust the position(s)
for best results. You may have to adjust the tuning of both the radio
and antenna several times for optimum results.

Source: http://www.bowdenshobbycircuits.info/

Touch Switch_MOSFET_Bipolar designs

2012-10-08T12:23:00.000-07:00

Touch Activated Light

The circuits below light a 20 watt lamp when the contacts are touched and the skin resistance is about 2 Megs or less. The circuit on the left uses a power MOSFET which turns on when the voltage between the source and gate is around 6 volts. The gate of the MOSFET draws no current so the voltage on the gate will be half the supply voltage or 6 volts when the resistance across the touch contacts is equal to the fixed resistance (2 Megs) between the source and gate. The circuit on the right uses three bipolar transistors to accomplish the same result with the touch contact referenced to the negative or ground end of the supply. Since the base of a bipolar transistor draws current and the current gain is usually less than 200, three transistors are needed to raise the microamp current level through the touch contacts to a couple amps needed by the light. For additional current, the lamp could be replaced with a 12 volt relay and diode across the coil.

Source: http://www.bowdenshobbycircuits.info/

Airband_Regen_2T_No audio amplification

2012-10-08T11:36:00.002-07:00

This is a great Super regen project from the great techlib.com site. It uses two transistors and crystal earphone or very high headphones like 2000 k ohms impedance one.
-----------------

Super-regenerative Air Band Radio

Pilar Ortega

Civil aviation still uses AM communications between 108MHz and 136MHz. It is fairly easy to build a receiver that operates on these frequencies, however, it will also be found easy to build a receiver that won’t tune high enough! The trick to getting the tuning range high enough is to use a high frequency transistor and VERY short leads. I used a BF199 transistor but a 2N2369 will probably work well too.

By far the most reliable construction method is ‘ugly’ construction on a 1 inch by 2 inch piece of copper clad board (I built this circuit on perforated board many years ago and it only just tuned high enough to receive my local airport signals). By using the copper foil as a ground plane we can mount components in mid air. This is more robust than it might seem because many components connect to decoupling capacitors that provide an anchor to the board. Keeping leads short reduces stray inductance and capacitance, and helps ensure stability and good tuning range. The circuit is based on an old one advertised in a hobby magazine many years ago, modified slightly.

The tuning coil ‘L’ is simply four turns of 0.8mm diameter wire with a diameter of 5mm. There is no former. The coil is compressed or expanded to adjust the tuning range. We need to arrange that we can just tune the upper end of the FM broadcast band when the tuning potentiometer is at minimum setting (wiper at the ground end). This will bring the Air Band into the main tuning range of the receiver. The antenna is a short telescopic one and couples with a ¾ turn link turn. Note that, if the coupling is too tight (the link too close to the main coil) then the regenerative stage will be too loaded and won’t oscillate.

The varicap diode ‘D’ was an unmarked component in my receiver, however, the BV409 should work admirably here. All capacitors with the exception of the electrolytic are ceramic. The transistors are best mounted upside down with their leads bent sideways.

No switch was used in my receiver. Instead, a stereo 3.5mm socket was used and the third contact used to switch the supply. Note that this trick only works when a mono plug is inserted! I mounted the earphone socket such that it traps the battery in one corner of the case. I expect this apparently cool solution is going to come back to bite me when I drop the radio, and the socket gets smashed off by the momentum of the battery!

In operation the regeneration control is increased until a rushing sound is heard. This noise indicates that the circuit is oscillating but will diminish when a signal is received. At this time the tuning and regeneration potentiometers can be adjusted for best reception. The receiver will be found to be most sensitive when the regeneration is set so that the circuit is just oscillating.

Purists will add an RF gain stage prior to the regenerative section, as this minimises coupling of oscillations to the antenna as well as adding sensitivity. In practise the circuit is sensitive enough but one should be aware that RF radiation from the antenna can interfere with nearby equipment, in particular, televisions.

If the circuit were operated on a plane it might well interfere with communications so on no account should this circuit be used near an actual plane. In any case, you would rightly be barred from bringing such items on a plane, let alone be permitted to use one!!!

Source: http://www.techlib.com/Pilar/pilarsprojects.htm

Airband_TRF_3T_1D_1IC_LM386

2012-10-08T00:11:00.000-07:00

Airband_Superheterodyne_2IC_SA602AN_LM324

2012-10-08T00:01:00.000-07:00

"Join a growing crowd of DX' listening enthusiasts who regularly tune in commercial air-to-ground and ground-to-air aeronautics communications. With this sensitive receiver you can hear them all, 747, A380, Piper Cubs, Fedex, and others! Picks up transmissions up to 130 miles away."
If, like many scanner enthusiasts and ham operators, you are interested in listening in on all the excitement manifest in aeronautic communication, but lack the equipment to pursue your interest, then maybe the Aviation-Band Receiver described in this article is for you. The Aviation Receiver, designed to tune the 118-135MHz band, features exceptional sensitivity, image rejection, signal-to-noise ratio, and stability. The receiver is ideally suited to listening in on ground and air communication associated with commercial airlines and general aviation.
Powered from a 9-volt alkaline battery, it can be taken along with your to local airports so that you won't miss a moment of the action. And even if you're nowhere near an airport, this little receiver will pick-up all the ground-to-air and vice-versa communications of any plane or ground facility within about 130 miles (190Km).

Circuit Description:
Figure 1 shows a schematic diagram of the Aviation Receiver--a super heterodyne AM (Amplitude Modulated) unit built around four IC's: an NE602 double balanced mixer (U1), an MC1350 linear IF amplifier (U2), an LM324 quad op-amp (U3), and an LM386 audio amplifier (U4).
In operation, an antenna that plugs into J1 picks up the AM signal. That signal is then coupled through C1 to a three-section, tuned-filter network consisting of L1-L5 and C2-C6. Signals in the 118-135Mhz VHF (Very High Frequency) range are coupled through C7 to a VHF transistor (Q1), where the signals are amplified. From there, the signals are fed through C8 to the input of U1 (the NE602 is a double balanced mixer), which in this application serves as a local oscillator. A variable inductor (Local Oscillator L6) and its associated capacitor network set the local oscillator frequency 10.7-MHz higher than the incoming 118-135MHz signals. A tuning network , consisting of varactor diode D1 and potentiometer R1, allows the local-oscillator frequency to be tuned across about 15MHz.
The 10.7-MHz difference between the received signal and the local-oscillator (LO) frequency (i.e., the Intermediate Frequency or IF) is output at pin 4 of U1 to a 10.7-MHz ceramic filter (FIL1). The filter is used to ensure a narrow pass band and sharp signal selectivity.
The output of FIL1 is amplified by Q2 and then fed through C16 to U2 (an MC1350 IF amplifier), which, as configured, also offers Automatic Gain Control (AGC), as we'll see shortly. The amplified 10.7-MHz IF signal is peaked using variable transformer T1. The AM audio is then demodulated by diode D2. After that, the audio is fed in sequence through four sections of U3 (a LM324 quad op-amp).
Note that a portion of U3-a's output signal is fed back through resistor R25 to the AGC-control input of U2 at pin 5. That signal is used to automatically decrease the gain of U2 when strong signals are present or to automatically increase U2's gain for weak signals. That keeps the output volume of the circuit within a comfortable listening range regardless of the strength of the incoming signals.
The receiver circuit also contains a squelch circuit that is controlled by potentiometer R3, which is used to kill random noise below a selected threshold level. When properly set, the squelch control virtually eliminates background noise, so that all you near are incoming signals that can be brought up to a usable level. Potentiometer R2 controls the overall volume fed through C26 to U4, an LM386 low-voltage audio amplifier. Due to the overall design and squelch control, the audio output is quite low in background noise, and yet it's capable of driving simple communications speaker or earphones to excellent volume levels.

Construction:
The Aviation Receiver was assembled on a Printed Circuit Board, measuring about 4-1/2 x 5-1/4 inches. Fig. 2 shows a full-size template of that printed circuit board's layout.
Although most of the parts for this project are commonly available through conventional electronic component suppliers, a source for some of the more difficult to find parts is given in the Parts List for those who prefer to do their own shopping. If you opt to gather your own parts or your plan to use what you have on hand, keep in mind that the circuit-board layout was designed to accommodate components of specific dimensions in some cases; jacks J1 and J2, switch S1, transformer T1, and all three potentiometers, for example. However, the potentiometers can be any model if you wish. Just wire them to the board.
Also note that either of the Siemens parts specified in the Parts list for varactor diode D1 will work, but both may be difficult to find from hobbyist sources. However, the second unit (BB505) is available from Allied Electronics.
However you go about collecting parts for this project, don't even think about building the receiver circuit without the printed-circuit board. At the frequencies involved, the placement of every wire and part, and even part value is critical for trouble-free performance.
Once you have obtained all of the components and the board for the Aviation Receiver, construction can begin. A parts-placement diagram is shown in Fig. 3. When assembling the project, take special care that polarity-sensitive components (electrolytic capacitors [keep leads as short as possible], diodes, and transistors) are installed properly. Just one part installed backwards can cause grievous harm!
Inductors (Aircoils) L1,L3,L5 can be made easily on a 5mm drill bit. Before you wind them, scrape the enamel of each end, about 5mm. Then wind the 1.5 turn (2-turns is okay too). I know it can be tricky especially if you have big fingers like me. Begin by installing the passive components (6 jumper wires, sockets, resistors, capacitors, inductors). Followed by installing the active components; diodes, transistors, and IC's. Once the active components have been installed, check your work for the usual construction errors; cold solder joints, misplaced or reversed-lead components, solder bridges, etc. Once you have determined that he circuit has been correctly assembled, it's time to consider the enclosure that will house the receiver.
The receiver's circuit board can be housed in any enclosure that you choose. Use the picture at the top of this project as an example if you wish.
The antenna for the Aviation receiver can be as simple as a 21-inch length of wire or telescopic antenna, or you can get a fancy roof-mounted aviation antenna. If you are near an airport, you'll get plenty of on-the-air action from the wire or telescopic antenna. But if you're more than a few miles away, a decent roof-mount (or scanner) antenna offers a big improvement.

Alignment & Adjustment:
Aligning the Aviation receiver consists of nothing more than adjusting the slug in the local-oscillator coil (L6) for the center of the desired tuning range, and peaking the IF transformer (T1). The receiver can be calibrated using a VHF RF signal generator, frequency counter, or another VHF receiver by setting R1 to its mid-position; remember that you want to set the local-oscillator frequency 10.7-MHz higher than the desired signal or range to be received.

Then, using a non-metallic alignment tool--a metal tool of any kind will drastically detune the coil, making alignment almost impossible--adjust the Local Oscillator coil L6 until you hear aircraft or aircraft communications. If you find that you're receiving a lot of FM broadcase stations, then you have adjusted the slug too far down into the coil. Turn it back until it is a bit higher than the coil form and try again. Once you're receiving aircraft or airport frequencies, adjust T1 for the best reception. Typically, T1 is adjusted 2-3 turns from the top of the shield can. If you don't have any signal-reference equipment or alignment, and are not yet hearing airplanes, your best bet is to pack-up the receiver and the necessary alignment tools, and head for the nearest airport! If the airport has no control tower, visit a general aviation center on the airport grounds, and ask which are the most active frequencies. Then adjust L6 and R1 until you hear the action. It should be obvious that alignment will test your patience if you do not live near a large airport.
Stretching L1, L3, and L5 at the antenna input will provide greater sensitivity if you have problems receiving a signal. Also, as mentioned before, ensure that L1, L3, and L5 are mounted a *little* bit above the pcb.
A ground-service operator or private pilot may be willing to give you a brief test transmission on the 122.8 Unicom frequency. And if your airport has ATIS transmissions you can get a steady test signal as soon as you are within line-of-sight of its antenna. (See the explanation of Unicom and ATIS down the bottom of this document). It is best to align the receiver right there at your local airport.

OMNI and VOR Transmissions:
If you can locate a tall white "cone" type of structure at your local airport or anywhere else such as a farmers field, then you have found a "VOR" or "OMNI" beacon, a VHF navigational aid for pilots. If you can find this (steady) signal it might help you in initial alignment of your receiver. Remember that you have to increase the local oscillator frequency later on in order to listen to air traffic communication.

Troubleshooting Suggestions:
If the receiver does not work at all, carefully check the obvious things first; battery wires and switch, and the connections to the speaker jack. Also, be sure to check that you've correctly installed all of the jumpers. If the circuit's operation is erratic, a solder connection is usually the culprit, or there could be break in the antenna or speaker wire. Did you install all 6 wire jumpers?
Pay special attention to the orientation of all IC's, transistors, diodes, and electrolytic capacitors. Also, be sure that C11 and C12 in SA602 (U1's oscillator circuit) are of the correct values. Local-oscillator operation can be verified with a simple VHF receiver or frequency counter. Remember that the local oscillator should be set to a frequency 10.7-MHz above the desired listening range. If the oscillator works, only a defective or incorrectly installed part can prevent the rest of the receiver circuit from functioning.

What You Can Expect to Hear:
No matter where you live, you will be able to receive at least the airborne side of many air-traffic communication. If you know where to tune, you can hear any aircraft that you can see, plus planes a hundreds miles away and more, since VHF signals travel "line-of-sight". Aircraft travelling at 45,000 feet and in "line-of-sight", can be heard.
Similarly, whatever ground stations you may hear are also determined by the line-of-sight character of VHF communication. If there are no major obstacles (tall buildings, hills, etc.,) between your antenna and an airport, you'll be able to hear both sides of many kinds of aviation communication. Be prepared for them to be fast and to the point, and for the same airplane to move to several different frequencies in the span of a few minutes!
At most metropolitan airports, pilots communicate with the FAA on a "Clearance Delivery" frequency to obtain approval or clearance of the intended flight plan, which is done before contacting ground control for taxi instructions.
From the control tower, ground movements on ramps and taxi ways are handled on the Ground Control Frequency, while runway and in-flight maneuvers near the airport (takeoff's, local traffic patterns, final approaches, and landings) are on the Tower Frequency. ATIS, or "Automatic Terminal Information System", is a repeated broadcast about basic weather information, runways in use, and any special information such as closed taxiways or runways. Such broadcast offers an excellent steady signal source for initial adjustment of your receiver, if you are close enough to the airport to receive ATIS.
Approach Control and Departure Control are air-traffic radar controller that coordinate all flight operations in the vicinity of busy metropolitan-airport areas. When you hear a pilot taking with "Jacksonville Center" or "Indianapolis Center", these are regional ATC (Air Traffic Control) centers. The aircraft is really en-route on a flight, rather than just leaving or approaching a destination. A pilot will be in touch with several different Regional Centers" during a cross-country flight.
Airports without control towers rely on the local Unicom frequency for strictly advisory communications between pilot and ground personnel, such as fuel service operators. The people on the ground can advise the pilot what they know about incoming or outgoing aircraft, but the pilot remains responsible for landing and take-off decisions. Typical Unicom frequencies are 122.8 and 123.0MHz.
The FAA's network of FSS (Flight Service Stations) keeps track of flight plans, provides weather briefings and other services to pilots. Some advisory radio communication takes place between pilots and a regional FSS. If there is an in your local area, but no airport control towers, the FSS radio frequency will stay interesting.

Pilot and Controller Talk:
Just to make sure you have a basic understanding of aviation chit-chat, here are a couple of examples what you may be hearing on your receiver. Don't blame the Aviation Receiver if all you hear are short bursts of words that don't make a lot of sense at first. Aviation communication is necessarily brief, but clear and full of meaning. Generally, pilots repeat exactly what they hear from a controller, so that both know the message or instructions were correctly interpreted. If you are listening in, it's hard to track everything said from a cockpit, particularly in big city areas. Just to taxi, takeoff, and fly a few minutes, all on different frequencies.
Here's the meaning of just a few typical communications:
"Miami Center, Delta 545 heavy out of three-zero-five." Delta Flight 545 acknowledges Miami Center's clearance to descend from 30,000 feet to 25,000 feet. The word "heavy" means that the plane is a Jumbo-Jet, perhaps a 747, DC-10, or LT-1011.
"Seneca 432 Lima cleared to outer marker. Contact tower 118.7" The local Approach Control is saying that the Piper Seneca with the N-number, or "tail-number" ending in "432-L" is cleared to continue flying an instrument approach to the outer marker (a precision radio beacon located near the airport), and should immediately call the airport radio control tower on 118.7 MHz. That message also implies that the controller does not expect to talk again with that aircraft.
"Cessna 723, squawk 6750, climb and maintain five thousand". A controller is telling the Cessna pilot to set the airplane's radar transponder to code "6750", and climb to and level off at the altitude of "5000 feet".
"United 330, traffic at 9 o'clock, 4 miles, altitude unknown." The controller alerts the United Airlines flight of radar contact with some other aircraft off to the pilot's left at a "9 o'clock" position. Since the unknown plane's altitude is also unknown, both controller and pilot realize that it is a smaller private plane not equipped with altitude-reporting equipment.

Parts List and other components:

Resistors:
All Resistors are 5%, 1/4-watt
                 R1,R2,R3 = 10K PCB mount potentiometers
R4,R9,R15,R16,R20,R21,R24 = 47K
    R5,R7,R11,R18,R25,R27 = 1K
                   R6,R28 = 270 ohm
           R8,R12,R17,R23 = 10K
                  R10,R14 = 1 Mega Ohm 
                  R13,R22 = 33K
                      R19 = 100K
                      R26 = 22K

Capacitors:
       C1,C7,C8,C13,C16 = 0.001uF, (1nF)ceramic disc (102, 1N)
               C2,C4,C6 = 82pF, NPO ceramic disc (82, 82p)
                  C3,C5 = 3.9pF, NPO ceramic disc (3.9, 3P9)
 C9,C17,C19,C20,C28,C30 = 0.01uF, NPO (10nF)ceramic disc (10N, 103, or Y5P103)
C10,C15,C21,C25,C26,C31 = 4.7 TO 10uF, 25WVDC, electrolytic
                    C11 = 10pF, NPO ceramic disc (10p, 10J)
                C12,C14 = 27pF, NPO ceramic disc (27p, 27J)
            C18,C27,C29 = 100 to 220uF, 25WVDC, electrolytic
                    C22 = 0.47uF, 25WVDC, electrolytic
                C23,C24 = 0.1uF, 25WVDC, electrolytic (104)
(NPO = standard for 'low-noise'. Caps have a black top.)

Inductors:
L1,L3,L5 = 1.5 turns #28 gauge magnet wire (wound on #29 or 3.5mm drill bit, 
              about 1mm spacing in between turns after installing to the pcb. 
   L2,L4 = 0.33uH, molded inductor* (Sayal 2/$1.00) DigiKey M9R33-ND, or M7807-ND)
             *M9R33-ND is Phenolic and more expensive. M7807-ND is Epoxy coated.
              or Miller #9230-08.  Colors Orange-Orange-Silver.
      L6 = 0.1uH, 3.5 turns, slug-tuned coil (DigiKey TK2816-ND) or TOKO
             #E528SN-100061 (orange, 10x7mm, see picture)
      T1 = 10.7MHz, shielded IF transformer (Mouser 42IF122, Brown cap color)
    Fil1 = 10.7MHz, ceramic filter (DigiKey, Murata type)

Semiconductors:
U1 = SA602AN (see note 1)
U2 = MC1350 or NTE746
U3 = LM324 or NTE987
U4 = LM386 or NTE823
Q1 = *2SC2570 (C2570), or NTE107, (Different Pinouts--click here!) NPN UHF silicon transistor 
Q2 = 2N3904, NPN transistor
D1 = BB505B, varactor diode
D2 = 1N270, OA95, 1N34, or NTE109, Glass Germanium Diode
D3 = 1N914, NTE519, 1N4148, BAX13, etc. glass silicon signal diode. 

*Printed Circuit Board is shown for the NTE107.

Additional Parts & Materials:  
  S1 = SPST switch, PC mount
  J1 = RCA jack, PC mount
  J2 = Subminiature phone jack, PC mount
  B1 = 9-volt alkaline battery
MISC = PCB materials, enclosure, 9V battery connector, battery holder, 
       wire, solder, knobs for potentiometers R1/R2/R3, antenna, etc.
    
See [UPDATES] in regards to modifications and changes.

Printed Circuit Board (PCB) Fig. 2, and Parts Assembly diagram (layout) is shown in Fig. 3 to make soldering the unit together a breeze!
Note: PCB pads for the ceramic 10.7MHz filter (Fil1) have been modified. The filter should fit perfectly now. Also, L6 in the parts layout diagram has been updated to reflect the square type TK2816-ND coil from Toko (PCB updated April 2, 2005).

Fig. 4. shows the finished assembly without the enclosure. Make sure the antenna-hole in the enclosure is in-line with the one on the pcb. On mine I used a stud with thread on both sides to enable me to use different length antenna's; all I have to do is unscrew the antenna and screw another antenna back in place without taking the receiver apart. In regards to the battery holder; you can also just use a piece of the double-sided foam tape if you wish.

Note 1: The SA602AN is an updated version of the NE405 type (made by Signetics). It is pin-to-pin compatible, and made by Philips. An even newer version is the SA612 and is also fully compatible with better filtering and noise suppression, it just has less gain at 45MHz. The SA602AN is a perfect match.
The SA602 is a rare and *very* hard to find IC and the price can be in the range of $4 to $6.00 in US currency.
Note 2: The varactor diode (D1) BB505 may also be difficult to get because it is obsolete. There is no replacement type for this varactor.
Note 3: The pin-out for transistor Q1 is very different for either 2SC2570 or the replacement NTE107. Click [HERE] for the diagram.

The following email was received by Matt Hagman to improve the performance:
"I found that the audio amplifier IC may require an 8ohm + 0.047uF load (in a snubber configuration) in order to prevent the tendency to oscillate at high > 300KHz frequencies."

Power consumption is minimum, the optional Led indicator will only add about 12mA. Most parts can be obtained via your local electronics store, mail-order, or a KIT.

Below is a picture explaining the importance to make the the coils L1, L3, & L5 as precisely as you can.

Some personal pictures showing a different kind of battery holder and a view of [inductors L1/L3/L5].

Abbreviations:

  ATIS - Automatic Terminal Information System.  Picked up usually close to the 
         airport.  The terminal parking lot is great for this.
   ATC - Air Traffic (Radar) Control.  Control Towers everywhere in the world.
   FAA - Federal Aviation Association (USA/Canada)
   FSS - Flight Service Stations.  The FAA's own network of Flight Service
         Stations which keep track of flight plans, weather information, and 
         other advisory communications.
Unicom - If an airport has no control tower of any kind, pilots rely on the 
         local "Unicom" frequency dedicated only to advisory communications 
         between pilots and ground personnel like refueling service operators.
         The typical Unicom frequencies aare 122.8 and 123.0 MHz. 
   VOR - or "OMNI" transmissions.  VHF navigational aid operating in the 
         118-135MHZ frequency range, just below air-ground comm range, sending 
         a steady signal (beacon).  If you can receive this signal remember to 
         increase the local oscillator frequency later to listen to all air 
         traffic communications.

Required Tools:

Soldering Iron, WLC100

Rosin Core Solder, thin

Small Needle Nose Pliers

Small Side (diagonal) cutters

Patience, patience, patience.

Other Helpful Tools:

Small Stainless Steel tweezers

Magnifying Glass

Helping Hands, or other PCB holding device

Desoldering tool, like braid, pump, etc.

Good Notes:

Tunes entire 118 -136 MHz Aviation band.

Easy tuning using one IF coil and one tuning coil (L6).

Operates on regular 9 volt alkaline battery.

Range 130 miles max (approximate) depending on type of antenna and location.

Receive control tower, aircraft-to-aircraft, maintenance, ground, ATIS, etc.

Squelch, and plenty of volume control.

Troubleshooting Help, again:
A "doesn't work" receiver can have a small problem or multiple problems related to the following examples below.
1 - Nothing works? Check for the obvious. Start with the Printed Circuit Board: check for solder splashes, hairline solder between tracks, un-etched copper, 'cold' solder joints, etc.
2 - Polarity of IC's, electrolytic capacitors, diodes, battery clip, switch, loudspeaker, placement, etc.
3 - Correct flat-side position for the two transistors? 4 - Correct value of ceramic capacitors at the correct locations?
5 - Correct values for C11 and C12 in the SA602 oscillator circuitry?
6 - Did all the above and still no signal? Get out the assembly instructions and re-check everything! An incorrect value resistor or capacitor is easy to miss.
7 - The working of the local oscillator can be checked with a simple VLF receiver or frequency counter. Remember that it is supposed to be set 10.7MHz above the desired listening range. If the oscillator works, only a defective or incorrectly installed part can prevent the rest of the receiver circuit from working.

Updates:
 2-09-2006  Added picture for D3 (1N914) to show 'Cathode' position.
 3-15-2006  Fine-tuned pcb again to fit new batch of different caps.  Adjusted 
            spacing between tracks to eliminate risk of 'hairline' shorts.
            Modified pads for NTE107 (Q1) only.  Watch orientation!
 3-05-2007  Fine-tuned pcb to better fit the standard Hammond enclosure.
            Printed Circuit Board measures 395 x 475 pixels, 2 colors!
 3-26-2007  Spaced out the pads to fit the BB505 horizontally.  Note that it can
            be mounted 'standing-up'.
 1-01-2009  KIT version obsolete.  Some parts hard to obtain or expensive.

Copyright and Credits:
Source: "Electronics Hobbyist Handbook", Spring 1994. Copyright © Fred Blechman and Gernsback Publications, Inc. 1994. (Gernsback Publishing is no longer in business).
Document updates & modifications, all diagrams, PCB/Layout, (C) Copyright by Tony van Roon.
Re-posting or taking graphics in any way or form of this project is expressly prohibited by international copyright laws.

Source: http://www.sentex.ca/~mec1995/circ/aviarx/aviarx.html

Airband_Regen_1T

2012-10-07T23:53:00.001-07:00

A Superregen Receiver for FM broadcast or Aircraft band AM reception

February 2004; Revised October 2006 by Rick Andersen

This is the receiver I was bragging about on the radio index page - the receiver that is so sensitive it can hear the local oscillator inside a small transistor radio 30-50 feet away. Build one of these little gems and you will be Able to hear aircraft pilots many miles away with nothing more than a 24 "whip antenna. The Superregenerative detector was popular, in its vacuum tube version, in the early days of VHF reception up through the late 1950's, early '60s. After that, it was found in its transistorized version in simple kits from Radio Shack, etc. It's also the reason for the noisy hissing sound made by the 27 MHz CB Walkie Talkies many of us had as kids. Though a lot of people have not even heard of it, and others think it's obsolete, the fact is that the superregen is still around in a specialized high-frequency applications. Our use of it here is a throwback to the old days when homebrew 'supergennys' were in vogue - as an extremely simple, yet extremely sensitive, broadband VHF receiver that will demodulate FM broadcast stations as well as AM aircraft band transmissions.
In the circuit below, Q1 serves as the superregen detector. Now this configuration is a strange beast, if you're only Casually acquainted with transistor circuit design. First of all, in the original 2004 Embodiment of this circuit, the signal was coupled into the collector circuit of the 2N3904 NPN transistor; Usually we connect the input to the base or emitter, and the collector is Considered to be an "output". Well it turns out that the high impedance of the LC tuned circuit, at the collector, makes it susceptible to outside influence, if we connect an antenna at that point ...... this circuit Teaches us that you can impress a signal on any lead of a transistor and take the output off any other leads, and the damn thing will still work!
In this revised version of Oct.. 2006, I've moved the antenna to the point between the top of the RF choke and the bottom of the emitter of Q1 - the aircraft picks up radio signals even better now than it did before. Again, there are several places where you could couple the signal in.

The tuning is a 15pF variable cap I happened to have lying around in my Junque box; the inductor "L" is nothing but a 2 "piece of # 20 stiff copper wire, bent into a" U "shape. If you squeeze that U into a near-bobby-pin shape, you will have eliminated most of the inductance, raising the frequency of the tuned circuit. You will have to experiment with the amount of "squeezing" you do to the wire; FM broadcast stations (88 - 108 MHz) will need more inductance, and the lower half of the Aircraft band (109-130 MHz approx.) will need less, since it's above the FM broadcast band.
The antenna has been changed from the February 2004 original of this article. Originally I had a 24 "whip, made of # 8 or # 10 solid copper wire, soldered to the ground plane and coupled to the L1 / C-tuning circuit through a 1 pF cap. My prototype was plagued with a lot of" dead spots "and" flutter "as I tuned across the dial. Adding a buffered input stage helped, but I later discovered the present method of making an antenna that worked even better, and allowed me to get rid of that extra input stage, with little change in sensitivity. The antenna is a 24-inch piece of plastic-coated # 20 or # 22 hookup wire, bent in the middle and folded back on itself, then twisted so that we now have a 12-inch "whip" with two connections at the bottom, roomates are soldered between (in series with) the emitter of Q1 and the little 6-turn RF choke that was made by winding # 22 enamelled wire on a BIC pen (the pen is used as a coil form and later removed.) Since very little inductance is wanted at VHF, my folding the antenna wire back on itself and then twisting its two halves together, gives it a "non-inductive" characteristic that Allows me to get 12 "of length without so much inductance as to spoil the circuit's operation around 110-130 MHz. This unusual antenna seems to work very well (plenty of sensitivity) and most of the dead spots and flutter are gone.
Just the make sure you build everything nice and tight - long, floppy leads are a disaster at VHF. I usually use 2 pieces of Radio Shack's 5x7 "copper clad board, connected together perpendicularly so as to make a bottom piece and a vertical front panel - an L-shaped chassis. Then I construct the circuit above this ground plane, using 10 megohm resistors as "standoff insulators" or posts, on top of the roomates I wire the circuit.
Positive feedback required for Oscillation is provided by the small 7PF cap from collector to emitter. You may need to increase of as much as this to the 10-15pF - or, try another transistor, if your detector will not oscillate. The way to tell that your detector is oscillating is to listen for a loud white-noise "rushing" sound from your amplified speakers, connected to the audio output of this radio. If all you hear is "quiet", it is not workin!
Q1's emitter has a 6 turn RF choke connected to it; below that chokes are a 10k resistor to ground and a .001 uf cap across that resistor. These three components form a subcircuit that makes the superregen unique: the Quench Oscillator. (The 10k resistor is also the emitter load across roomates we take roomates audio is sent to the second transistor, Q2, for amplification).
Here's how it works - and I'm giving all this detail Because so many people have no clue about the mysterious goings-on inside this circuit:
The 330K + resistor provides bias to turn Q1 on. The .001 uF cap on the base provides an RF ground at the base. Like a normal regenerative detector, if there is enough positive feedback, the transistor will oscillate. However, in a normal regen, we find that the most sensitive reception Occurs at the point just before Oscillation sets in; after that, we get a heterodyne squeal if there is a carrier present in the signal being received. In a superregen, we interrupt the buildup of feedback, between about 20.000 to 30.000 times per second, with a lower-frequency Sawtooth waveform that is automatically produced in that three-component Mentioned Earlier subcircuit. The .001 uF cap across the 10K resistor forms an RC time-constant circuit that sets the "quenching frequency". It turns out that if we alternately "quench" (interrupt) and then buildup the feedback, at> 20 kHz (above the range of human hearing), we can Effectively drive the transistor much farther into the range where positive feedback would have resulted in self-Oscillation. Ie, by delaying the onset of Oscillation, or chopping it up, we Effectively operate in a much more sensitive region of the transistor's bias. We hear practically down to the "noise floor", and we get fantastic sensitivity.
The drawbacks? The frequency response is much broader than a normal regen detector - in fact, the superregen can only "hear" broad (wide-bandwidth) signals like FM radio stations with their 200 kHz-wide deviation. Narrow-band FM is not well- detected by this circuit. The detection method itself is known as Slope Detection, and you may notice that FM music stations are a bit hard to tune in Cleary; there always seems to be a little bit of distortion. AM Aircraft transmissions, on the other hand, come in clear as a bell, and the broadness of tuning, roomates would be a serious disadvantage in a professional receiver, works to our advantage in this simple radio. The reason I say this is that aircraft transmissions growing niche to be short, choppy remarks, and the pilot may be on one frequency, while the tower may be on another, so that a selective radio will hear only one side of the conversation. Often This receiver will pick up both sides, if they're near enough in frequency . My homebrew version of this receiver tunes from approximately 112 to 130-ish MHz; the band actually extends to 174 MHz.
This circuit has been around for a long time; I did not invent it. I did, however, come up with an enhancement based on another radio design found in these pages - the Reflex Receiver: I connected a 12k ohm resistor in series with a .47 uF capacitor; this pair is connected from the bottom of the RF choke back to Q1's base. Essentially this is feeding back some audio (with 25 KHz quench waveform) roomates I find boosts the audio gain and also gives it a fuller, slightly "bassier" sound, Compared to the "tinny" sound I got before putting the pair in the RC.
A .47 uF cap blocks Q1's emitter DC voltage while passing the audio to an RC low-pass filter (22k, .01 uF) at Q2's base; the RC filter gets rid of most of the RF, leaving the audio intact. Q2 amplifies the audio signal and the output is coupled through a 2.2uF electrolytic to an output jack. I found that the addition of the .047 uF cap to ground was Necessary to Kill the observed tendency for stray RF to interact with the Radio Shack Amplified Speaker through the connecting cable, an instability Caused roomates with my roomates varied hand position near the radio. The cap also softens the "tinniness" some more.
Even though this unbuffered Superregen probably does not radiate very much noise, I would not bring this radio anywhere near an airport, especially in these days of terrorist threats paranoid! I would not want to find out that I was Causing any interference to aircraft or communications tower! I live about 30 miles from Harrisburg, PA, and have no trouble at all receiving pilots' transmissions as they enter and leave the area. So you do not have to be close to the airport to hear aircraft communications. Being way up in the air, the planes' transmissions are receivable for many miles around.
I hope you'll take the time to build one of these almost-forgotten Superregen circuits and see how well they can hear, for such a simple circuit. Just be ready to do a little futzing around with parts layout, etc., Before it will work smoothly. Be ready to the make slight substitutions, try another transistor if the circuit will not oscillate, and understand that you'll have to "calibrate" the receiver for the band you're interested in (FM or Aircraft) by custom-bending the U -shaped wire that is "L". Take my 2 "length for the main inductor" L "as a starting point; you may need to modify its length to get your radio into the correct frequency band.

Back

Source: http://translate.googleusercontent.com/translate_c?depth=1&hl=en&ie=UTF8&prev=_t&rurl=translate.google.com&sl=id&tl=en&twu=1&u=http://www.ke3ij.com/superrgn.htm&usg=ALkJrhiVu8fAtQANA1-w06P2kzvbhhNrfA

--------------------------------------------------
The same receiver after modifications
---------------------------------------------------

Make Airband Radio Receiver Simple

July 13, 2010

by: Kamarudin
blog: arjip.wordpress.com
(Must copy and paste this article as long as the source list, thanks)
Airband is the radio frequency bands used for communications between the pilots with the airport tower. This track is actually closed for public communication purposes, but that does not mean we can not monitor them.
Radio receivers, radio scanners, radio General coverage usually has features Airband receiver so it can be used to monitor the Communication Flight. flight communication is only used for the purposes of commercial aviation and not for the military.
communication between the aircraft could be heard high tower kilo kilometers, this is because the plane flew at a height so that the signal radiated far enough. Airband frequency is 118-136 MHz VHF and the system dijalur AM. this range is based on the line VHF Line of Sight (LOS). so long as we can still see the plane sebuat directly then we can monitor communications.
Radio Scanner or radio receiver equipped Airband reception point in the market is very expensive. to it in my post this time, would like to discuss how to create a simple Airband Receiver or radio communication receivers flight path. why the circuit can be very simple? it is because the type of receiver is the "super-regenerative receiver". generally radio receiver (receiver) that are sold are based on the type of "heterodyne" which of course is more expensive and complicated circuit.
I mentioned this circuit is a modification of the original series created by Rick Andersen. article from Rick Andersen can be seen by clicking HERE .
you can learn a lot about the "super-regenarative receiver" on his website Rick Andersen , because I originally learned from the articles on the site. Airband receiver using component version of Rick Andersen 2N3904 transistor, this transistor can be quite difficult in Indonesia.
therefore I modify it with other VHF transistors are 2SC930 transistor C930 or, more easily obtainable.
you can modify this setting by using another type of transistor, the transistor origin they will be working on the VHF and UHF.

for the layout of PCB (Printed Circuit Board) of this series can be seen by clicking HERE .
for components of "tuning" I took from the former tuning radio 3 band (AM, FM, SW1), tuning components can be easily searched in electronics stores.

circuit is not equipped with sound amplifier or amplifier, is required for audio reinforcement.
for a suitable amplifier circuit please click HERE .
amplifier circuit versions are also suitable, please click HERE .
The following is a series of photos that have been equipped with sound amplifier (amplifier).

can use the antenna to antenna cable with a length of 120 cm and is positioned vertically, known as the "half-wave vertical antenna". my posts are still concerned about the "half-wave vertical antenna" can be seen HERE . could also use a telescopic antenna (whip) are commonly used in portable radios. for better results can use an external antenna ground plane specifically for Airband frequencies.
for more details about the "Antenna ground plane for Airband" please click HERE .
actually by simply using telescopic antenna is very adequate, because the radio regenerative and super-regenerative receiver has advantages in sensitivity (sensitivity) for signal reception. Airband if you want to amplify the signal to be more far-reaching acceptance, then please add a signal booster (booster). post article can be seen HERE .
to use the power supply 9 Volt battery, or use 2 pieces @ CellPhone battery 4.2 Volt in stacking and connected in series.
from my experience the results are less good adapter, air oscillation circuit is difficult and this may be due to the flow of the adapter is not as smooth of a battery. I myself use 2 cell laptop batteries former diseri (@ 4.2 volts) so that can be charged out at any time. if the series did not start working normally after some time of usage, the battery may have started to run out and immediately replace it with a new or gunkan battery can charge.
how the operation:
(Ampliifier, antenna and battery must be installed correctly)
Regen potensio turn up missing and the screeching sound of a hissing sound change "hizzz", such as FM radio sound in an empty frequency. hissed, indicating that this series started insulated and working normally. when the series began insulated, then the sensitivity of the signal is very high. if "REGEN control" plus continue the sensitivity is reduced. if there is no hissing sound then it means the circuit is not insulated, double-check the circuit you created. there may be a relationship between the components that are less fit. if this is the case then try to replace it with another transistor. rotary tuning to find the frequency that is being used. when there is an incoming signal, hiss will automatically disappear and become conversational voice communication. communication path is characterized Airband "clear and concise". so the communication went very cepat.cobalah monitor busy hour flight time, then you will see a lot of conversations Airband lines of communication (communication typically use English).
attention:
because this circuit using active oscillator that serves as a detector AM, it is not advisable to bring this tool in the aircraft cabin. because of interference can disrupt communications tower pilot with the airport. should be ok, if you operate this tool at home. if you want to make Airband receiver that does not use the oscillator (passive circuit), please visit this article: -> " Passive Aircraft Receiver ".
Update June 1, 2012
please visit this continuation of my post, which was discussed Airband radio receiver.
on my recent post is titled " Make-airband radio receiver portable ", click HERE to see it.

Source: http://translate.google.com/translate?js=y&prev=_t&hl=en&ie=UTF-8&layout=1&eotf=1&u=http%3A%2F%2Farjip.wordpress.com%2F2010%2F07%2F13%2Fmembuat-radio-airband-receiver-sederhana%2F&sl=id&tl=en

-----------------------------
PCB for the same receiver:
-----------------------------

This PCB (single side) layout is based from my version Airband receiver schematic circuit.
its no need to make some hole or drill in PCB, because all part directly soldered into PCB and part placed above circuit.
you can see the schematic and my article about “Regenerative Airband Receiver” in this LINK.
my article about “Regenerative Airband Receiver” is originally from my self experience to built some simple Regenerative Airband Receiver.
this PCB layout can be modified for added some small sound amplifier circuit or modified in size for suitable with some “Box”.
at prototype which I make, have been provided with simple amplifier circuit with IC LM 386.

you can see my article about “mini audio Amplifier for tuner or simple receiver” in this LINK, or my article about “Three Transistor Mini Amplifier for Tuner or Simple Receiver” in this LINK.

Schematics of Genius Russian Receivers _ Regenerative and Reflex

2012-10-03T20:06:00.000-07:00

Before you start keep my earlier post about the equivalent transistors handy unless you are a "purist" and want to build the rigs on original parts from ebay.com.
I found those circuits simple efficient clearly by handling the regeneration in different ways.
As if the main focus was is to use less components still it is modern in depending on LM386 instead of output transformers for audio. You can refer to Sir Douglas for the old-fashioned receivers. Still those receivers are different in less dependance on transformers as feedback way to get the regeneration or the reflex.

Part One

Part Two

This also a great archive of the Russian old receivers

Receivers classified according to different methods of function

2012-10-03T19:27:00.002-07:00

TRF is a receiver that works by amplifying the received frequency by several stages and those stages should be tuned to the received frequency to make the most of it. ZN414 is an IC example of this technology.

Regen is a receiver that works by +ve feedback of the RF.

Reflex is a receiver that works by feedback of the audio mixed with feedback of the RF. Mainly the feedback of the audio is negative to mitigate the positive feedback of the Regen. In other words the Reflex is a Regen that have audio signal fed back with RF.

Superregen is the a Regen receiver but with a smooth-regen and higher sensitivity. Superregen involves RF amplifier stage before the Regen stage. Also, Frequency-quench stage is involved.

Any Superregen and Regen is able to detect SSB and CW without need for BFO!

Direct Conversion = Homodyne = Synchrodyne = Zero-IF
It is a receiver that works by making the IF frequency zero.
NE602 and NE612 are examples of ICs that may be used for this technology. This technology involves a local oscillator that produce a frequency that equals the received carrier frequency.

Superhet is a receiver that works by conversion of any detected frequency to IF=0.455MHz or 10MHz. Local Oscillator works to produce a frequency higher than the received frequency by the IF amount. The multiplication of the two frequencies produce the IF. Sometimes the Local Oscillator is called VFO. The usual envelope-detector may be used after the IF amplifier stages to detect the audio signal. Several IF stages produce higher selectivity and sensitivity as well. Now, to detect the SSB we need another Stage of BFO which give a frequency higher than the IF by ~1kHz or less by ~1kHz which is to detect the USB or LSB and CW. this stage is multiplied by the IF before the envelope detector.

كيف تعمل اجهزة الاستلام؟

الار تي اف –التضخيم المباشر للاشارة المستلمة قبل كشفها

يعمل بواسطة تضخيم الاشارة المتلمة بعدة مراحل ويتم ضبط هذه المراحل اي تنغيمها على نفس الذبذبة المستلمة وتعتبر الشريحة من نوع ZN414 مثل على هذا التطبيق

الريجن –معيد التوليد

وهو مستلم يعمل بواسطة التغذية الموجبة للاشارة الراديوية المستلمة RF

الرفلكس –اي العكوس او الانعكاسي

وهو مستلم يعمل بواسطة تغذية الاشارة الصوتية ومزجها مع تغذية الاشارة الراديوية ولكن تكون الاشارة الصوتية الراجعة بشكل تغذية سالبة على الاغلب لتخفيف قوة التغذية الموجبة للاشارة الراديوية بكلمة اخرى يعتبر المستلم العكوس مستلم من نوع معيد التوليد مع اضافة وهي ارجاع للاشارة الصوتية

السوبر ريجن او معيد التوليد الممتاز

وهو مستلم من نوع معيد التوليد لكن بشكل سلس ويمتلك حساسية اعلى وانتقائية اعلى والانتقائية هي القابلية على فصل الاشارات المتقاربة بالتردد. يمتلك هذا النوع من المستلمات دائرة تضخيم للاشارة الراديوية مع دائرة خنق ذبذبي تقوم بفلترة الاشارة الصوتية قبل كشفها وتضخيمها

يعتبر كل مستلم من نوع معيد التوليد او معيد التوليد الممتاز مستطيعا لاستلام اشارات الاس اس بي اي اشارات ارسال حزمة الارسال وحيدة الجانب واشارات السي دبليو اي اشارات الارسال المستمر او التلغراف والتي تكون بتقطيع الموجة الحاملة بشكل نقطة شارطة لماذا لان هذين النوعين يستطيعان توليد اشارة ارسال محلية تختلط مع الاشارة المستلمة فتقوم بكشف هذا النوع من الاشارات وبذلك ليس هناك داعي لوجود مرسل ضربات والذي يسمى بي اف او كما في دوائر السوبرهيتروداين

دوائر الاستلام من نوع التحويل المباشر او الذبذبة المثلية او الذبذبة المتزامنة او الذبذبة الوسيطة الصفرية

هذا النوع من المستلمات يعمل بواسطة ذبذبة وسطية مقدارها صفر

وتعتبر الشرائح الالكترونية من نوع NE602 و نوع NE612 امثلة على شرائح تستخدم في هذه التكنلوجيا ويقوم هذا المستلم بتوليد ذبذبة محلية مساوية للاشارة المستلمة اي الذبذبة الحاملة.

دوائر استلام السوبرهيتروداين اي الذبذبة المخالفة

وكلمة سوبر هنا تعني سوبرسونك اي فوق صوتي لان الذبذبة بعد خلطها تكون فوق صوتية اقصد الاشارة الوسيطة فوق صوتية

يعمل هذا المستلم بواسطة تحويل اي اشارة مستلمة اي تردد وسطي مقداره IF=0.455MHz or 10MHz وذلك بواسطة مذبذب وسطي يقوم بتقديم اشارة مقدارها يزيد ترددا على الاشارة المستلمة بمقدار ثابت وهو مقدار التردد الوسطي وبعد ذلك تكون هناك عدد من مراحل تضخيم الاشارة الوسطية المستلمة لزيادة الحساسية والانتقائية للاشارة المستلمة. المذبذب المحلي يسمى في اف او ويتلو مراحل تضخيم التردد الوسطي هذا مرحلة كشف الصوت بواسطة كاشف الضرف وهو عبارة عن دايود اي ثنائي اشباه موصلات. ولغرض كشف اشارات الحزمة الجانبية الوحيدة اس اس بي يتم وضع مذبذب ضربات اضافي يسمى بي اف او ويقوم بارسال تردد يزيد او ينقص عن تردد الآي اف او التردد المحلي بــ واحد كيلوهيرتز وبذلك يتم تكوين صوت من الموجة الحاملة لكشف اشارت السي دبليو او التلغراف المرسل او كشف اشارات الاس اس بي وتكون حالتي الاستلام بضرب التردد الوسطي باعلى منه او اقل منه لغرض كشف نوعي الاشارة اس اس بي وهما يو اس بي او ال اس بي وهما الحزبة الجانبية الوحيدة العليا والسفلى.

مع تحياتي لجميع مصنعين اجهزة الاستلام والارسال العرب

Morse Code Chart in a geometric Sense

2010-12-28T17:24:00.000-08:00

I like the idea of this chart because it make some sense!
You can her the whole alphabet of morse as midi file (download it first).

download

Source: http://9w2pju.hamradio.my/2009/09/morse-code-chart.html

LEARN MORSE CODE in one minute !
This is a code listening tool. Print it on your printer.
Place your pencil where it says START and listen to morse code.
Move down and to the right every time you hear a DIT (a dot).
Move down and to the left every time you hear a DAH (a dash).
Here's an example: You hear DAH DIT DIT which is a dash then dot then dot.
You start at START and hear a DAH then move down and left to the T and then you hear a DIT so you move down and RIGHT to the N and then you hear another DIT so you move DOWN and RIGHT again and land on the D
You then write down the letter D on your code copy paper and jump back to START waiting for your next letter.
The key to learning the code is hearing it and comprehending it while you hear it.
The only way to get there is to practice 10 minutes a day.
Listen to code tapes or computer practice code while tracing out this chart and you will find yourself writing down the letters in no time at all without the aid of the chart.
The chart brings repetition together with recognition, which you don't get from any other type of code practice aid.

HEAR slow morse code This code speed is slow enough to follow the chart above.

LEARN the DITs and DAHs with these MP3 files:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 1 2 3 4 5 6 7 8 9 0

And the character to emphasize that there she was, she was walking down the street, is :
do-wah-diddy-diddy-dum-diddy-do

Goto DOWNLOADS page for hours of MP3 code practice
email KB3BYT

HOW TO LEARN MORSE CODE AND ENJOY IT

FOX HUNTING ANTENNA PLANS

source: http://www.learnmorsecode.com/

This introduction is my best to the subject:

How to learn morse code. And enjoy it.
Morse code is not a chore. Its a challenge.
Its a challenge of your ability to learn a new language.
And it is truly a language.
There are millions of people who successfully learn a foreign language
so you can be certain that its not so farfetched to think that you too may learn a new language.
The secret to learning a language is to jump into the pool, over your head, totally emerse yourself in your new language.
If you want to speak Chinese then the best way to learn Chinese is to go to China and only hear Chinese.
We all can't do that.
But we can come real close with today's recording technologies with cassette tapes and DVD and CD and MP3 recordings.
Morse code is the same. Listen to it. All the time. It doesn't matter if its just slow or just fast.
It doesn't matter if you do not understand a single word at first.
There are a dozen methods to practice and get your brain to retain what the letters are.
Practice reinforces and recognition will come with practice.
Then... one day ... you start hearing entire words and sentences that make sense..at speeds that
you never dreamed you would understand.
Some peple say that you should never use a chart or any visual aid to learn morse code.
All people are created a bit different and what works for some people , does not always work for everyone else.
So don't try just one method to learn morse code. Try a few and decide what works best for you.
This chart at http://www.learnmorsecode.com is just one of many methods to learn morse code.
This particular method will work for all ages to immediately put together the noise of morse code with the meaning
of the noise. It does not matter if it is a slow process. All that matters is that your brain gets a chance to connect the dots and make some meaning out of it all.
Many people give up trying to learn morse code beacuse they do not ever get the noise to stick in their brain and recognise what letter they just heard.
This method will sew together that recognition if you practice this method for 10 minutes every day with the
SLOW code A-Z file.
After you no longer need the chart...then...and only then....move on to the faster code practice download files.
There are computer programs that can make morse code to teach you.
I like the software at http://www.g4fon.net/
I highly recommend you use that software to learn the letters and also to make your own practice audio files.
If you can not make a computer do recordings and carry around MP3 files
then use cassette tapes. They are cheap to make and WALLMART sells casette players for $5.00 now.
The computer programs that generate practice morse code are great
and FREE so have fun with it.
One method to learn morse code is called CODE QUICK.
CODE QUICK has you listen to a letter and associate small sentences with the sounds
of the morse code. An example of this method is to hear the letter K in morse code
which is made up of the sounds DAH DIT DAH.
You hear the DAH DIT DAH and it actually sounds like KANG ga ROOOOO.
So your brain hears the DAH DIT DAH and injects KANGAROO into your minds eye
and you say AH HAA!!!! KANGAROO begins with a K so what I just heard was a K !!!!!
You write down the K and along comes the next letter.
There are SOUND ALIKES for every letter of the alphabet and numbers too.
You are encouraged to make up your own sound alikes for the
letters if you have trouble using the CODE QUICK sound alikes.
CODE QUICK taught me morse code at a time where no other method worked for me.
I did not learn about the LEARNMORSECODE.COM chart until years after I used CODE QUICK.
You can BUY code quick at http://www.cq2k.com for around $30.
The methods used at code quick are very straight forward and actually have been around
for many many years before the code quick author published the first code quick
casette tapes and work book course.
I have an uncle that was a code listener during the Vietnam war and one day he visited
me during a morse code contest and very fast morse code was playing on my radio and it
was was too fast for me to understand and my uncle sat down next to me and asked me what I
was doing and I told him I was trying to understand the hailing station but I was too new at
it to understand.
My uncle told me what the station was saying and then told me about his code listening days
so I asked him to respond and he told me that he never sent a single dit in all those years.
All they did was spy on the enemy.
He understood the fastest of the code so I asked my uncle to explain to me the method that
the army used to teach him the code in 1965 and he told me that the army made them memorise little
phrases like a baby crying wants his mother to give him a drink of water and
that sounds like MaWAWA and is the letter W ...DIT DAH DAH.
That just blew my mind because that was precisely what CODE QUICK used to remember W also.
This man was a high speed spy listener that got his first morse code training with this learning method.
So this method truly works but you will have your sticks in the mud old farts telling you
that CODE QUICK sound alikes will only slow you down from learning truly high speed morse code at 20 words per minute.
Well to hell with sticks in the mud.
If you learn morse code at 5 words per minute using sound alikes and have fun with listening
to any morse code then moving up to high speed code will be another challenge and practice
is what makes perfect.
You will find that if you know 5 words per minute slow speed morse code and you listen to
ramp recordings where the letters are played slow at first and then ramp up to real fast
code of the same letters, the ramped up speed will stick to your brain quite
well because you already knew what the slow letters sounded like and you will enjoy the
comprehension instead of being all wrapped up in being lost in fast practice code.

So thats my 2 cents on learning morse code.
Have fun.
from Rob KB3BYT
source: http://www.learnmorsecode.com/

Airband_VHF_1T_Regen_High gain audio amp required

2010-12-19T19:37:00.000-08:00

Parts:
R1, R3    =    47K 1/4W Resistor
R2    =    10K 1/4W Resistor
R4    =    4.7K 1/4W Resistor
R5    =    5K Linear Taper Pot
R6    =    2.2K 1/4W Resistor

C1, C2 =       0.001uF Ceramic Disc Capacitor
C3, C6    =    0.001uF Ceramic Disc Capacitor

C4    =    2.2pF Ceramic Disc Capacitor
C5    =    1pF Ceramic Disc Capacitor
C7    =    15uF 15V Electrolytic Capacitor
C8    =    18pF Variable Capacitor
D1    =    1N82 Diode
Q1    =    2N918 NPN Transistor
L1    =    See Notes
L2    =    1.8uH Inductor
ANT1    =    Approx. 18 Inch Wire Antenna
MISC    =    PC Board, Wire, Knob For C8

The communications between commercial aircraft and the ground can be interesting, amusing and sometimes even disturbing. However radios that receive the approximately 220MHz to 400MHz band commonly used for aircraft (both military and commercial) are not easily found. And scanners can be complicated, large and expensive. With an easy to build circuit such as this one, everyone can enjoy listening in on these conversations.

# The circuit originally appeared in the Think Tank column of the Sept. 1995 issue of Popular Electronics.

# L1 is made by winding 2 turns of 22 AWG magnet wire on a 5/32 drill bit. This inductor can be modified to shift the frequency range of the circuit.

# The antenna can also be placed at the anode of D1 if overload is a problem with it connected to the emitter of Q1

# R5 adjusts regen and thus sensitivity.

Source: http://www.project-world.co.cc/links/schematics/radios/ABS.html

MW_3T_Reflexive

2010-12-18T16:47:00.000-08:00