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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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8th Dec 2016, 5:29 pm | #1 |
Tetrode
Join Date: Feb 2006
Location: Newport Pagnell, Buckinghamshire, UK.
Posts: 95
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Airmec Oscillator 304: Any Information?
I've just been given one of these monsters and can find no useful information on it...
It's clearly a siggen but a jolly high power one judging by the EL34 in the output stage What was its original use give that it's intended to be rack mounted? I reckon I could use it as a perfectly functional QRP CW TX if I can work out a good method of keying it!!! It works bar the meter not working and appears in reasonably calibration but on the low frequency ranges there is significant sparking across the output stage anode tuning capacitor. This is not caused by dust - an airline has seen to that... On the top range its output at around 89MHz is enough to fully swamp BBC R2 on one of my Bush VHF64s a good few feet away!!! I can find no manuals or circuit diagrams for it on the web at all. If anyone has any pointer to one I'd be grateful before I commence drawing out the circuit by hand... It is vaguely similar in some respects to the Airmec CT212 but has no AM/FM modulator... It's been got at in the past as the EL34 anode load resistor has been replaced by an odd chain of low value carbon and wirewound resistors... This is perhaps why there is arcing across the tuning capacitor? Any information will be most appreciated. Many thanks
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Jim G4MEZ |
8th Dec 2016, 9:05 pm | #2 |
Heptode
Join Date: Jun 2010
Location: Zurich, Switzerland
Posts: 538
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Re: Airmec Oscillator 304: Any Information?
Hi Jim,
maybe you can ask him:http://www.kleines-roehrenmuseum.de/Messgeraete.htm or possibly: www.vmarsmanuals.co.ok/archive/files_index.htm Radiomusem knows it too. http://www.radiomuseum.org/r/airmec_...ator_304a.html than I`m suhre, sombody from forum knows more in detail... regards-Karl |
8th Dec 2016, 10:06 pm | #3 |
Heptode
Join Date: Jun 2006
Location: Milton Keynes, Buckinghamshire, UK.
Posts: 931
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Re: Airmec Oscillator 304: Any Information?
Jim, I had a quick dig around in my files to see whether I successfully found anything useful from when I first came across it (was in the job lot my Bush VHF-71 came in I think), but sadly the only thing in the folder is a text file stating "no useful references yet found".
I'm as curious as you as to the origins of the thing and intended use. Sounds like there are some bits of design that are just odd enough to be really interesting and make you wonder why on earth they did that in there...
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Zel's Lair - A random bag of vintage tech, lighting information and other assorted geekery Last edited by Zelandeth; 8th Dec 2016 at 10:07 pm. Reason: Fixed a touch-screen induced typo. |
8th Dec 2016, 10:32 pm | #4 |
Nonode
Join Date: Jun 2013
Location: Surbiton, SW London, UK.
Posts: 2,801
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Re: Airmec Oscillator 304: Any Information?
The same model was continued under the Racal brand name. I have used one as a
50MHz CW beacon. The manual can be obtained from: http://www.telford-electronics.co.uk/manual.php?alpha |
9th Dec 2016, 10:45 am | #5 | |
Tetrode
Join Date: Feb 2006
Location: Newport Pagnell, Buckinghamshire, UK.
Posts: 95
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Re: Airmec Oscillator 304: Any Information?
Quote:
Thanks for looking through your stuff Restoration73... Yes, The Racal one was the 304A I believe. I saw a picture of it on the web and it just looks a tad more modern... Interested that you used one as a 50MHz beacon. How did you key it? Thanks for the manual source Off to look there now...
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Jim G4MEZ |
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9th Dec 2016, 4:12 pm | #6 |
Tetrode
Join Date: Feb 2006
Location: Newport Pagnell, Buckinghamshire, UK.
Posts: 95
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Re: Airmec Oscillator 304: Any Information?
I gave Telford Electronics a try for the manual but sadly they no longer stock it...
I will now sketch it out longhand over the coming weeks as all other avenues looks to be exhausted...
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Jim G4MEZ |