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Author Topic: WWI, WWII and other POW homebrewing radios  (Read 21982 times)
AE6HR
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Posts: 10


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« on: February 01, 2003, 07:02:13 PM »

I am the grandson of a WWII Army Aircorps gunner.  Because of this, and my father's insane interested in history (it is contagious you know), I have done a lot of reading about the different wars as well as watching those wonderful (??) documentaries on various history channels.

Quite often, both my father and I, have heard of POWs making receivers or tranceivers (in rare cases) from things they could scrounge in some of the war prison camps they were in.  I have spent some time, so has my father (who isn't a HAM [yet], but once was GROL, back in his college years), trying to find information in books or on the INTERNET about such feats.  I would like to find information that gives how some of them accomplished this.  I can see them getting their hands on things to be inductors and capacitors, but have had a hard time figuring out crystals (if used), resistors, and other required parts.

Does anyone know of such reference material?

73,
Trever Adams
AE6HR
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WA4PTZ
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Posts: 528




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« Reply #1 on: February 02, 2003, 08:17:01 AM »

Considering what it took to make a receiver during
WWII I'd have to say that a crystal receiver would
be the only type that could have been used and it
would have been very difficult to find parts to make even that.
The arrival of "solid state" changed the entire world
and opened the door to many more possibilties.
The movies and TV often lose their technical
credibility when it comes to communications and
even navigation during WWII. As a history buff myself,
it is a facinating subject. It seems unbelievable
the advances that we made during WWII and since. It
might even be proof of a supreme being.
73 and enjoy - Tim
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K5CEY
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Posts: 217




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« Reply #2 on: February 03, 2003, 02:18:20 PM »

This brings to mind the "Fox Hole Radio" of the WWII era. The detector was a rusty razor blade with a piece of pencil lead resting against it. Resistors can be made by drawing heavy lines on a piece of paper with a lead pencil. In the early days of grid leak and regenerative receivers, it was common practice to draw a line with a pencil on the tube base between the grid and filament pins to form the grid resistor.
            John  k5CEY
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WB6BYU
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Posts: 13234




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« Reply #3 on: February 03, 2003, 03:15:42 PM »

There have been several cases of POW radios described
in the RSGB journal RadCom, and reprinted in the
Technical Topics Scrapbooks (available from the ARRL).
These were generally regenerative receivers (which were
quite common in the '30s and before, and gave high
gain with a single tube and minimum parts.)

From what I can remember, capacitors were made by
winding foil gum wrappers with waxed paper, coils were
wound on toilet paper tubes with wire salvaged from
old motors, etc.  Tubes were either smuggled in, or
salvaged from accessible equipment.

Such equipment is of special interest to Pat Hawker
G3VA, who has been writing the Technical Topics column
in RadCom for over 45 years.  Pat was in Special
Communications during WWII, and has described a number
of sets used by undercover agents during the war.
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AE6HR
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Posts: 10


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« Reply #4 on: February 05, 2003, 04:26:43 PM »

Thank you very much to all of you who answered.  Some of you did a wonderful job of helping me find information.  I am trying to located the appropriate periodicals or books at this moment.

Cheers.
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K5LXP
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Posts: 4479


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« Reply #5 on: February 07, 2003, 09:35:43 AM »

A closely related topic is foxhole radios, which GI's built out of whatever was available.  A google search on "Foxhole Radio" netted thousands of hits, many of which also mentioned POW radios in the result.

Mark K5LXP
Albuquerque, NM
k5lxp@arrl.net

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AB9GR
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Posts: 1




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« Reply #6 on: March 20, 2003, 10:12:03 PM »

Check out the following website.  Pretty amazing stuff if you ask me.

http://www.armyradio.co.uk/Default.htm?http&&&www.armyradio.co.uk/publish/Articles/William_Howard_Japan/Japanese_POW_Radio.htm

Walter
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VE3LYX
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Posts: 141




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« Reply #7 on: December 27, 2011, 05:30:35 PM »

POW radio.
I am curretly building such a radio. I have the grid leak resistor made, the wooden tube socket , the tuning capacitor from soup can lids is done but just needs final tweaking (bending) I have made the grid leak capacitor but it is too small so I have to remake it but I have a plan. I have the toilet paper roll and will look for the copper style electric fence wire around my farm tomorrow if it is not raining. I also found a broken headphone set and now have one ear piece.  The project is coming together  but it is my 2012 radio project.
A regen has everything a transmitter has. The main difference is plate voltage. A regen operates just under the oscilation pont and most keep it there by limiting the plate voltage. A tx or power osc as I tend to call 1 tube transmitters differs only in the lack of an ear phone and the installation of a CW key of sorts in the cathode circuit and a higher or unrestricted plate voltage. Lest you think not I have already made and operated a 1 tube hartley regen which becomes a transmitter with the flip of a DPDT switch. I am taking this project as a challenge and started looking for stuff about 7 months back including saving soup can lids. I will let you know how it turns out. I expect to be able to recv and transmit . The problems as one builds it are not where you might think. The design is out of my head , no schematic. It will be not easy but it will be fun. Regens are the most under-rated recvrs on the planet. A good one will give your (and my ) modern rice box a run for its money in sensitivty. They are just difficult to run which is their big drawback.
Coil data. Freq in metres or wavelengh in metres divided by four will give you the number of turns on the coil to get you in the ball park. All errors on the short side . Not a perfect way to  caculate but certainly practical. Interesting subject.
Don VE3LYX
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G3RZP
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Posts: 4557




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« Reply #8 on: December 28, 2011, 04:14:30 AM »

The post war RSGB Bulletins have a number of articles on POW receivers. I believe the rx built in a POW camp by Shackleton, G6XN is somewhere in the Imperial War Museum in London. Some POWs in Japanese hands actually built a transmitter - where they got the 6L6s from, I don't know, but were found with it before it could be used. The court martial thought it was a receiver, otherwise they would have been executed.

The RSGB had a prisoner of war fund organised by C.H.L. (Eddie) Edwards, G8TL, that sent parcels of things like toothpaste, tobacco, razor blades etc, as well as books. But the RSGB Radio Amateur Handbook was not allowed because it would give too much information to POWs wanting to build radios! One or two POWs had the handbook on them when captured and somehow managed to keep it. The RSGB handbook became very important to the war effort: delivery of 3000 copies was made on September 2, 1939, amid doubts as to how many would be sold. By the end of the war, they had sold 185,000 copies as it became a standard text book for service personnel to buy.
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KA5N
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Posts: 4380




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« Reply #9 on: December 28, 2011, 06:17:27 AM »

The best "crystal" detector was a Gillette blued razor blade which were widely available at the time.  The blued area formed a diode with the unblued steel of the blade.  Add a coil with slider and earphones and viola!  A radio.
These unfortunate fellows had lots of time on their hands and many chances to scrounge parts.  In war time there is lots of damaged equipment that is discarded and therefore
available for building more complicated equipment for the POWs.

Allen
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VE3LYX
Member

Posts: 141




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« Reply #10 on: December 28, 2011, 08:15:53 AM »

The copperweld fence wire is not suitable for radio work i discovered. too much resistance SO I removed a switch from the wall on the house and relocated it on the next closest stud. that gave me 2 inches of old papaer wrapped 14.2  wire. (The XYL had asked me if I  could move the switch for her but it would be doable in the field as well. ) I used the white and the black to make a 40M hartley coil with the joint in the middle being the centre tap.  It is wound on a TP roll. I also believe it or not found a discarded 171  4 pin tube with "weak?" Written on it. It was sitting free inside another piece of equipment.  Getting close to smoke test time.
Don VE3LYX
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VE3LYX
Member

Posts: 141




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« Reply #11 on: October 24, 2012, 02:54:42 PM »

With my apologies I post this. I am sorry it is so late .
POW radio project was completed and works. First reception was Radio Spain from Barcelona. A piano recitale. Operation and some good views are posted on You tube under POW radio.  And yes I tested it. It will also transmit with a increase in plate voltage. One of the most interesting and fun projects I ever built. I powered it as would have been then with a bevy of dead batteries that had been disposed of. Needed 48 volts for regen as ther is no regen control. Just get adding them till I heard the HISSS. Radio is discuised as a bird house. Tested it there too.  I put it on the porch and had a chickadee sitting on the perch (also the variable cap tuning knob) When you go to You tube and click on the one with the reception turn up your volume full. It works but it isnt loud. This was actually the very first fire up and I recorded it with my camera between my ear and the earphone. Hard to make pictures and sound both that way so I made two films.
Don
« Last Edit: October 24, 2012, 02:58:40 PM by VE3LYX » Logged
VE3LYX
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Posts: 141




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« Reply #12 on: October 30, 2012, 04:22:10 AM »

Here is the second time I had it running. It really surprised me how well it worked. The station is Barcelona Spain and they were brodcasting a piano recital. Here is the recording I made with my camera in my ear between the earphone and me. The stills are pictures I made along the way during the build. I wound up with a 56 tube. I found  as the 171 did not want to perform in this circuit.  The wiring used was removed from the house live as a POW would have done. The variable cap was made frm soup can lids punched with a nail and bolted together with screws removed from old furniture. The grid leak is made from discarded pie plates and paper nailed together with the resistor made from a pencil line drawn on the wood and thickened till it worked. The tube socket was made from wood with wire shoved down the holes and then the tube inserted. The coil is a toilet paper roll wound with the stolen house wiring. The circuit is a Hartley osc (powered with discarded batteries till it was just under oscillation which is how a regen actualy works. the circuit is essentially the same)with a earphone in the plate circuit and a hand made RF choke wound on a broken pencil. The earphone was part of a broken set found in the mud at the local dump by a neighbour. The set was also tested as a birdhouse (because it must be disguisable) and as you can see it was a roaring success. My wife said it took less then a minute before this chickadee sat on the tuning knob. All in all a real interesting project. The success was greater then I would have thought. I was just as surprised as you will be. The video lost some volume on uploading to You tube so turn your sound up please. I hope you enjoy it. http://www.youtube.com/watch?v=9M2T5qozfjs
don Ve3LYX
Oh yeah. It will also transmit by bypassing the earphone and upping the voltage. Not too bad a signal either.
« Last Edit: October 30, 2012, 04:31:35 AM by VE3LYX » Logged
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