HOWTO build a radio in a POW camp -- the real life King Rat
BJ: Can I just ask you - the components for the low voltage battery cells that you produced, where did you get all the components from?Construction of Radio Equipment in a Japanese POW Camp (via Make)RGW: Well, zinc wasn't hard, there was some sheet zinc lying on the aerodrome and we pinched quite a bit of that because that would be eaten away during the use of the cells for the low voltage. I don't know what would have happened if that ran out. I think someone produced two lantern cells which did for a while, but it was mainly on this home-made cell system, which wasn't efficient but nowhere near as inefficient as the rectifier was. We must have been consuming... Ah Ping said he had to turn up a lot of power to keep the lights what they wanted. We were dispersing such an amount of power in this four test tube rectifier for the high tension.
A variable capacitor was another component we had to bring in. We couldn't make a variable capacitor, it was impossible. We had to take two plates off the one we had to get a high enough frequency. Yes, I can't remember why we didn't go up a bit in inductance; it was largely a trial and error business really. Except that in a regenerative receiver you had some idea when you were near a station because the receiver was so sensitive as all regenerative receivers are.
It had a piece of meat skewer type wood which I had a hole drilled in by a pen-knife, and we glued this in with some of our glue or something, into the capacitor shaft so that we could tune it by holding a little stick across it, fixing it at about six inches because one couldn't get one's hands any closer to the set because it was in a state of very near oscillation where the maximum sensitivity is, just before it bursts into oscillation. With a fairly clear HF band, it wasn't long before we knew roughly, by putting a couple of marks on the stick, where it was. We knew that the Voice of America was due for a transmission and I don't think we ever knew the frequencies because the BBC didn't announce frequencies, they just came on the air and broadcast.
the latest
latest episodes
"The rules governing play within Eve would not have sanctioned Ricdic if he had simply stolen the cash and used it in the game, nor if he had bought kredits with real dollars."
We seriously need to retire the word sanction. So, the rules would have allowed him to keep playing if he hadn't sold the fake money? Or, the would have penalized him even if he hadn't sold the fake money? I'm so confused.
Words shouldn't be their own antonym.
"A variable capacitor was another component we had to bring in. We couldn't make a variable capacitor, it was impossible."
I don't quite understand why this would be. Variable caps are incredibly easy to make, and those that are made can be hidden a heck of a lot easier than something manufactured.
I hope nobody will offend the people involved in this story by mentioning McGyver. Folks, this is not a movie but serious hacking done in a prison camp during wartime.
A different story that many HAMS and radio enthusiasts will probably already know is what happened to the Airship Italia and the way the radio helped some of the crew to get rescued.
http://translate.google.com/translate?prev=hp&hl=en&js=n&u=http%3A%2F%2Fwww.radiomarconi.com%2Fmarconi%2Fbiagi.html&sl=it&tl=en&history_state0=
A pretty good movie (The Red Tent) was made after this story.
propose a method then.
But how do you build a digital to analog converter?
@#5: You should have applied for a voucher before the deadline. If in the US, they would have gladly helped you get one for almost free.
A variable capacitor can be built with sheet metal and air or different dielectric.
http://www.eham.net/articles/5217
Also, resistors can be built by using the graphite that can be found into a normal pencil.
http://en.wikipedia.org/wiki/Graphite
Another good way to make a variable cap is to create a gimmick capacitor. Take an insulated wire, cut it in two, then twist it together.
I have an RCA Radiola 17 which was manufactured in 1927 - has just such a capacitor in it. There is another capacitor in the radio that was made out two sheets of metal and some paper.
Making the gimmick capacitor would have been one of the safest ways to do this. If it is found, it is just a small length of wire, nothing more.
Fantastic!
The interview shows not only the story of the immensely illegal radios, but is a beautiful example of how geeks of the 1940's were, and remain, exactly as incomprehensible to us non-electro types as their modern day counterparts. I'm guessing the good Colonel's inability to speak common language is only because of his supreme geekdom, and not a result of his advanced age. I'd bet a dollar no one understood what the hell he was talking about in 1942 either!
I lived many years on Outram Road, across the street from the site of what was once Outram Gaol, the kempetai's in-city torture chambers. They brought prisoners from Changi who'd stepped too far across the line there, and it was not common for anyone to ever return. You have not truly experienced King Rat until you've read it across the road from Outram, imagining the ghosts swirling about you as you turn the pages.
Colonel Wells is as brave a man as men are made. His light banter about his deprivations suffered at the hands of the Japanese only shows to greater detail the extent of his courage.
Firstly wouldn't a crystal set be far easier to make? They had a good aerial and ground and it requires no active components.
Ok the regenerative oscillator is a fairly simple receiver to make, but its drawback is it puts out its own rf so could be a give-away if there was radio communication equipment at the camp. It also require high voltage dc (as described in the article) to drive the tube.
Regenerative receivers have actually made a comeback recently in short range wireless connections.
@10 A crystal set is significantly less sensitive than a regenerative receiver.
Furthermore, although it would radiate, it is unlikely anyone would notice it or bother locating it. The local Japanese wouldn't be all that likely to listen to the BBC. And from any distance it isn't likely that anyone would notice a swish from some remote regenerative receiver.