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Homebrew Equipment A place to show, design and discuss the weird and wonderful electronic creations from the hands of individual members. |
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9th Jun 2017, 6:43 pm | #41 |
Dekatron
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
Posts: 6,130
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Re: P.O.W. Radio?
Or one could say that their perception is their reality.
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Mending is better than Ending (cf Brave New World by Aldous Huxley) |
9th Jun 2017, 6:47 pm | #42 |
Heptode
Join Date: Sep 2006
Location: Woodbridge, Suffolk, UK.
Posts: 643
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Re: P.O.W. Radio?
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Dave G1AGK. My perception is my reality! |
9th Jun 2017, 11:09 pm | #43 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 4,108
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Re: P.O.W. Radio?
Ah well, may turn up in another auction in 10yrs time, by which time it could be 'genuine' courtesy of a few months sitting somewhere damp!. We'll see
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19th Aug 2017, 9:06 am | #44 | |
Heptode
Join Date: Mar 2008
Location: Forest of Dean, Gloucestershire, UK.
Posts: 648
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Re: P.O.W. Radio?
It's a while since this thread was last active but for the sake of completeness here are some more examples of PW constructed receivers.
https://www.awm.gov.au/collection/C221800 https://www.awm.gov.au/collection/C1002932 http://www.bobkelsey.net/wireless.html The second link contains this quote, which is attributed to the SBO at Changi : Quote:
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19th Aug 2017, 11:02 am | #45 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,349
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Re: P.O.W. Radio?
It bears a strong resemblance to the "Superboy" razorblade radio!
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20th Aug 2017, 2:27 pm | #46 |
Pentode
Join Date: Jul 2009
Location: Roxburghshire, UK.
Posts: 196
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Re: P.O.W. Radio?
Was Superboy sponsored by elastoplast?
Colin. |
20th Aug 2017, 4:04 pm | #47 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,349
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Re: P.O.W. Radio?
"Blue" refers to the original Blue Gillette blades made of ordinary steel that were all you could get from Gillette and other makers before Wilkinson Sword brought out their stainless steel blades in the 1960's. I found a couple in my late father's shaving kit. Although they were coated with a blue lacquer (hence the suggestion of scraping with a nail file), they did tend to get rusty unless they were very carefully dried after use. I understand that the rusty parts might have provided better rectification.
Before H&S, you learned to be careful! I remember using an old naked razor blade to strip the insulation from the wire I used to connect up the signals and points of my train set, and never came to harm. You could buy a metal holder for old razor blades in stationers, and in the 1960's schoolchildren would often have one in their pencil box for sharpening pencils. I lost mine years ago. |
20th Aug 2017, 5:09 pm | #48 | |
Rest in Peace
Join Date: Jan 2015
Location: Cottesmore, East Midlands, UK.
Posts: 858
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Re: P.O.W. Radio?
Quote:
I was always under the impression that the blue finish on Gillette blades was temper blueing from the blades' heat treatment and it was this oxide that provided the semiconductor properties to allow one to be used as a makeshift diode. Whatever it was, it did little to prevent the darn things rusting very quickly! Cheers, Frank |
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20th Aug 2017, 6:01 pm | #49 |
Rest in Peace
Join Date: Feb 2004
Location: Hexham, Northumberland, UK.
Posts: 2,234
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Re: P.O.W. Radio?
I seem to remember the use of razor blades with a sort of metal edging type holder for cutting out balsa parts for making model aircraft back in the day. I never remember injuring myself. Then I had the luxury of an X-Acto proper model knife. I think scalpel blades were used as well. A while ago I went through a spell of crystal set enthusiasm and tried various household items for a detector, including coke and coal. I found that it is surprising what will work as long as the signal is pretty strong, as it is where I live, around 5 miles from a 50kW AM broadcast station. It is fascinating and becomes a bit of an obsession if you're not careful.
Alan. |
20th Aug 2017, 8:05 pm | #50 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,349
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Re: P.O.W. Radio?
Possibly oxide treatment was used originally: the ones I have must date from the late 1960's (Dad died at the end of 1968), and I think are a different shade of blue from the ones I remember seeing in the 1950's. The blue surface is very uniform and glossy, which looks like lacquer to me. However, if it is lacquer, then it must be very thin: scraping does appear to remove what must be a very thin surface layer to reveal a lighter underlayer before bare metal is revealed, leaving an extremely small amount of "swarf" on the blade I was scraping with. It seems unlike the finish of the blued or blackened steel that I have come across, but I am no expert and there must be many different chemical surface finishes. On the rare occasions that I have scraped chemically coloured metal, the bare metal has been exposed directly with no intermediate shade.
My primary school teacher used to keep a single-sided razor blade in the pencil tray on her desk which we were not allowed to touch, but which she used to sharpen pencils. I think they were branded Ever Ready (not the same as the battery company) and had a substantial metal channel over what would have been the second blade on a normal safety razor blade that made them easier to handle. I have one that came with a BIB cassette repair kit for use with its splicing block. |
20th Aug 2017, 10:28 pm | #51 | |
Rest in Peace
Join Date: Jan 2015
Location: Cottesmore, East Midlands, UK.
Posts: 858
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Re: P.O.W. Radio?
I think you're right in that Gillette changed their blue blade - just found the following reference to them:
Quote:
Cheers, Frank Last edited by frankmcvey; 20th Aug 2017 at 10:39 pm. |
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21st Aug 2017, 10:22 am | #52 |
Octode
Join Date: Feb 2009
Location: Bletchley, Buckinghamshire, UK.
Posts: 1,223
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Re: P.O.W. Radio?
Single sided razor blades were standard kit for sound engineers before digital recording took over. We used them all the time for editing tape.
I never wanted to know what some of the musicians did with them... |
26th Sep 2017, 1:45 pm | #53 |
Pentode
Join Date: May 2011
Location: Enniskillen, Fermanagh, UK.
Posts: 188
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Re: P.O.W. Radio?
Looking for something else, I fell over this and just had to post a photo, I've no connection to it. Taken from :- the Lou Albert Collection
Sept 30/Oct 1 2017 at the Guides Hall, 6 Lamington Drive (off Burton), Warner's Bay, NSW |
26th Sep 2017, 3:40 pm | #54 |
Guest
Posts: n/a
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Re: P.O.W. Radio?
And for those of you that don't want to pay for Microsoft Office the free Openoffice opens this file too.
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26th Sep 2017, 4:22 pm | #55 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,642
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Re: P.O.W. Radio?
Wordpad opens it in W10 (and W7 I think) if you don't have one of the office suites
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26th Sep 2017, 7:33 pm | #56 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: P.O.W. Radio?
The locals made quite a few Xtal sets in the Channel Islands during WW2.
Lawrence. |
22nd Oct 2017, 10:30 pm | #57 |
Rest in Peace
Join Date: Sep 2010
Location: Ripley, Derbyshire, UK.
Posts: 785
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Re: P.O.W. Radio?
I stand correcting, but I think that the DLR earpiece is rather too low in impedance to give any useful audio from a crystal set, let alone one with that type of inefficient detector plus the unlikeliness of having a decent aerial and earth to make up for the deficiencies stated.
I think its "phoney" to be polite.... Tony |
22nd Oct 2017, 10:41 pm | #58 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,289
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Re: P.O.W. Radio?
I have found that low impedance headphones work perfectly well with crystal sets. Apparently they're not good for the 'Q' of the tuned circuit though.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |