When I was digging into the history of the RS-1 and GRC-109 sets crystals naturally came up. In the CIA's online "Reading Room" of declassified rabbit holes I found a document that stated that the CIA held over 12 million crystals in inventory in the early 1960's. (Sorry, I did not write down the Doc number but it's there...) I wonder what happened to all of those.
I do remember seeing a 55 gallon drum full of FT-243 crystals at one store on New York's Radio Row in the mid 1960s. 25 cents a piece, I bought a bunch; any useful "ham freqs" were about a foot below the surface... And I learned that QSY-ing crystals was a skill I did not have...hihi
I have purposely bought as many FT-243 crystals as I could in any frequency below the 40 meter band, then I etch them to a chosen frequency with Whink Rust Remover. It is slow, but works well. I am slowly accumulating 40 meter crystals beginning at 7000 kHz every 5 kHz to the top of the band.
80 meter crystals are hard to find and 160 meter rocks are just plain scarce to non-existent. 60 meter crystals might be a bit easier.
One can also get artist's glass etcher at hobby stores. Both contain hydro-flouric acid, which is dangerous stuff even at low strength.
Ken W7EKB
Sent via the Samsung Galaxy S21 5G, an AT&T 5G smartphone
Subject: Re: [ARC5] Odd Freq FT-243 you looking for
Are the frequencies on the crystals
channel or crystal frequency?
If channel frequency and receive crystal, the crystal frequency
could be a by offset by an if frequency and a multiple of the
crystal frequency.
Glenn
WB4UIV
On 7/31/2023 3:12 PM, Paul Thekan
wrote:
Thanks again to all that responded to my post
yesterday for info on crystal mfr's during the war.
As I slowly go througj the pile of xtals
here...I'll be happy to keep a look out for any non ham band
freqs you may want. So far out of 350 xtals looked at , only
two 40 mtr xtals were found.
So far the highest freg found is around 8mcs.
The bulk so far is around 5 -6.9 mcs and others in the 4mc
range.
Also have quite a few DC 34 xtals as used on the
BC669 , these all in the 4 mc range.
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"