Prisoner of war  radio amateurs - Page 1
Forum section: electronics / beginners

author: M0BSW
author_rank: Frequent Contributor
timestamp: August 03, 2013, 05:49:29 pm
content: I've been reading a book about, prisoners of war making radio's to here what was going on in the war front, risking their lifes , making these radio's as the would have been shot if found, any way these people were in my opinion the real radio amateurs, making the sets from what ever they could find, so I got to thinking about making a capacitor to start with and made this one , got a measurement of 2988 pf going to find ways of making other parts and see if I can make a simple radio.

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 03, 2013, 06:14:01 pm
content: your intention to go on war and designing radio while in the field does not interest me. what interest me is the picture. +1to LC200A, since its the one sitting on my bench now(made a simple rig to ease smd insertion for it) and oh, try to improve your focus, your topic is about diy cap, not lc meter. i'm not sure what type you are trying to build, try googling butterfly cap, it'll be fun DIYing.

author: M0BSW
author_rank: Frequent Contributor
timestamp: August 03, 2013, 06:22:47 pm
content: Quote from: Mechatrommer on August 03, 2013, 06:14:01 pmHa Ha, I bought this wun hung low device for making a coil, it's never let me down, my cap sorry about the focusing , was two strips of foil separate by cling film , first attempt, I'm not going to war , just fascinated about how they did it., have you noticed on the side of this LC meter there is a socket for the computer , any idea what its for, because I havent. focusing I used my DSLR Canon EOS 1 that was at 20 ft away couldn't be bothered to change lens, I'm a lazy old bugger.

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 03, 2013, 09:04:49 pm
content: Quote from: M0BSW on August 03, 2013, 06:22:47 pmthat mini USB port? i believe its 5V power supply only. i wont bother since i used wallwart (or battery if portable)Quote from: M0BSW on August 03, 2013, 06:22:47 pmtry manual focus (little switch at the side of lens) or separate auto-focus (half-press), recompose and snap. no need to change lens your lens should be allright. sure EOS1D user could do betteredit: and increase aperture to >= f8 or something (and ISO as well if necessary) to increase depth of field to include reading at the backgroundand my exif read it as eos500d not eos1fwiw...

author: Unknown
author_rank: Unknown
timestamp: August 03, 2013, 09:21:52 pm
content: The hardest thing to make would be the detection diode... but even that can be bodged (with care) from a razor blade and graphite.http://en.wikipedia.org/wiki/Crystal_radio

author: EpicIntelGamer
author_rank: Regular Contributor
timestamp: August 03, 2013, 09:36:10 pm
content: I'm definitely going to watch this thread closely, and I just might make a foxhole radio of my own, now that I notice I have a ton of magnet wire left over.

author: IanB
author_rank: Super Contributor
timestamp: August 03, 2013, 09:39:58 pm
content: The simplest radio I ever made was a long wire strung up between poles in the garden, a metal post stuck in the ground for the other terminal, and a telephone earpiece between the two to listen. I don't recall if I even needed a diode to detect the signal, and there was certainly no tuning. I think BBC Radio 2 was the strongest signal by far and it swamped everything else. It was rather amusing to hear so much noise coming out of a wire strung up in the air.

author: M0BSW
author_rank: Frequent Contributor
timestamp: August 04, 2013, 06:33:55 am
content: Quote from: Mechatrommer on August 03, 2013, 09:04:49 pmShows how long it's been since I used it, your right I just lookat it eos 500d, I must really use both more, all the gear no Idea

author: G7PSK
author_rank: Super Contributor
timestamp: August 04, 2013, 08:48:27 am
content: I once read something similar about POW making radios out of light bulbs, not sure if they were just using the filament wire for cats whiskers or actually making valves, but they actually made transmitters in some cases. The SOE smuggled miniature tubes into europe and the POW camps in some cases but I don't think this happened in the far east so it was down to scrounging whatever came to hand.

author: djsb
author_rank: Super Contributor
timestamp: August 04, 2013, 12:11:46 pm
content: What's the book called? You might also be interested in a book called "Most secret war " by R V Jones. It's about the development of Radar during WW2.David.

author: saturation
author_rank: Super Contributor
timestamp: August 04, 2013, 12:41:07 pm
content: You could make an AM radio, reception only, without power with nothing but some cardboard, stiff paper or wood, wire and slab of galena; they were called crystal radios. The hardest part was making the speaker; it had to be sensitive enough to work with AM signals. The detector was a diode formed by a cat whisker and the tuner was an inductance coil. Without galena, you could try any mineral that had diode like action, like a quartz crystal.https://en.wikipedia.org/wiki/Cat's-whisker_detectorAt toy stores for $10By WWII, most techies of the time would have built a crystal radio, it was fairly popular in the 1920-30s, so it was common knowledge how to rig one up.http://kf4lmt.wordpress.com/2012/01/13/andersonville-historic-site-trip/

author: M0BSW
author_rank: Frequent Contributor
timestamp: August 04, 2013, 02:11:27 pm
content: Quote from: saturation on August 04, 2013, 12:41:07 pmThank You ,by looking at the picture I can see how the razor blade was used, still very clever though.

author: G7PSK
author_rank: Super Contributor
timestamp: August 04, 2013, 08:49:02 pm
content: Quote from: djsb on August 04, 2013, 12:11:46 pmThats the problem I read the book in the school library in 1967 and although I can remember about the radios I cannot remember the book title, I would love to read it again.