[Boatanchors] How did they "pinpoint" frequencies way back when?

[g4gjl]

Robert, Phil et al,

I can confirm that the BC-221 was in use here in many intercept stations.
These were imported from US along with hundreds of AR88s and HRO receivers.
This was part of the American support for the British War Effort, but
probably did not occur until late 1940, Im not sure of the dates.  Thank you
America!

There were British crystal calibrators in use in the intercept stations
before that, but I don't have details of these, except that the cal signals
were distributed to multiple work stations and multiple receivers on demand
of the operators from a centralised point. This was because crystals were in
short supply here..

The Regular Army used the Class D wavemeter Mk I and MkII versions, both
much inferior to the BC221, The Navy had a wide range of Crystal calibrators
and heterodyne wave meters, but ther seens little info available on
thesenow. Judging by what turns up at ham junk sales, rallies etc, the BC221
dominated.

 I know for a fact that the HROs were used at Bletchley and the outlying Y
Stations (The intercept stations used to garner German enciphered traffic).
The receivers were kept on 24/7 as they were generally manned continuously.

Also the RAF used the AR88s (AR88Ds and AR88LFs, I believe) in a modified
form....they added a hideous white (YES WHITE) bakelite panel to the lower
left corner of the RX. These receivers were also used by the secret
intercept services.
The mods bypassed the mains switch and drilled the front panel to fit a
British bakelite toggle switch for mains and also a high impedance 1/4''
phone jack to the front panel. The Jack was fed from the audio final via a
0.1uF capacitor. The panel partially covered the range switch decals for
range 1. The mod spoilt the appearance of the receiver, but has now become
part of War history, so to speak! Why they did it remains a
mystery....nothing wrong with low impedance headphones and the mains switch
assembly on the rotary function switch is a good quality one.

Regards to all and a Happy easter also

Pete
G4GJL



----- Original Message -----
From: <WA5CAB@cs.com>
To: <boatanchors@mailman.qth.net>
Sent: Sunday, April 11, 2004 5:27 AM
Subject: Re: [Boatanchors] How did they "pinpoint" frequencies way back
when?


> I don't recall what the Brits used but any US intercept station would have
> had one or more BC-221's for setting receivers accurately on frequency (if
they
> felt the need).  I have several (60+ actually but I don't use all of
them).
> The pair of BC-221-AK's made in 1943 or late 1942 that I routinely use
here at
> the house are good for +/- 500 Hz if I'm being sloppy and lazy.  They're
both
> older than I am (barely) and probably work better.  :-)
>
> But the receivers that were commonly used for this sort of work would
mostly
> not have been the tactical sets like the BC-312 or BC-342.  They would
have
> used less common sets like the Super Pro series, HRO, BC-903 (NC-100A),
etc. (or
> whatever the Brit equivalent was), which have better resetability.
>
> In a message dated 4/10/2004 11:06:25 PM Central Daylight Time,
> gzook@yahoo.com writes:
> > How did "intercept ops" accurately set their receivers
> > for expected incoming messages?
> >
>
> Robert Downs - Houston
> <http://www.wa5cab.com> (Web Store)
> <wa5cab@cs.com> (Primary email)
> <wa5cab@houston.rr.com> (Backup email)
>
>
> --- StripMime Report -- processed MIME parts ---
> multipart/alternative
>   text/plain (text body -- kept)
>   text/html
> The reason this message is shown is because the post was in HTML
> or had an attachment.  Attachments are not allowed.  To learn how
> to post in Plain-Text go to: http://www.expita.com/nomime.html  ---
> _______________________________________________
> Boatanchors mailing list
> Boatanchors@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/boatanchors
> ** List Administrator - Duane Fischer, W8DBF/W9WZE **
> ** For Assistance: dfischer@usol.com **
> $$ For vintage radio info, see the HCI web site $$
> http://www.w9wze.org