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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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1st Oct 2017, 11:38 pm | #21 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,642
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Re: ID This Device?
It's the physical aspect that intrigues me. Four pins commoned at one side, the B4 pattern may be just to fit available sockets, but a screw terminal at the other?.
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1st Oct 2017, 11:48 pm | #22 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,876
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Re: ID This Device?
Is it just a terminal, or is it also a gap adjuster?
David
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2nd Oct 2017, 7:27 am | #23 |
Heptode
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 773
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Re: ID This Device?
I think the plug-in base and the terminal may indicate that the equipment that used the crystal could change frequency but not as fast as, say, swapping a 10X type. The 4BA tapped hole in the underside of the base may indicate that the crystal(s) were firmly mounted, so again not a quick job to swap freqs.
The terminal is just that, there is no locking nut or other adjustment to the threaded rod part. The Trawler Band was often marked on domestic sets, as were aircraft bands but I can't recall seeing those bands on pre-WW2 sets, any domestic set collectors care to comment? I will see if I can find some info on the 1947 Atlantic City Conference when a lot changed as regards frequency allocations. I can recall reading objections by European nations to amateur use of 1750-2000kHz ("Top Band") which might indicate when 2MHz began to be used by ships and 2017kHz in particular. Roger Last edited by G3VKM_Roger; 2nd Oct 2017 at 7:36 am. Reason: add |
4th Oct 2017, 7:39 am | #24 |
Heptode
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 773
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Re: ID This Device?
A brief search turned up the frequency allocations agreed at Atlantic City in 1947. 2182kHz is mentioned as the R/T distress freq and the band my crystal is in is allocated to the Mobile Service, which I assume includes Maritime Mobile.
However, IMHO the crystal I have has a pre-war origin, by 1947 much smaller crystals with internationally agreed holder types were abundant. Thanks for the interest from members, who I know always like a mystery! Roger |