[Boatanchors] How did they "pinpoint" frequencies way back when?
Ray, W2EC
[email protected]
Sun, 11 Apr 2004 01:06:17 -0400
In addition to being quite stable once warmed up, and they were usually
left on all the time as Glen indicates, the vernier scales on the freq
dials were very accurate and repeatable. No, you couldn't read out the
freq to a 100 cycles (or even a kilocycle) with the dials available,
but once you found a frequency and recorded the vernier setting, it was
very easy to just return to that vernier setting and be pretty much dead
on frequency. That's why so many of the receivers of that era had the
frequency label sheets on the panel, so the vernier setting for a
particular frequency could be recorded for other operators. So if an
operator on duty was to monitor for a signal on 6003kc and that
frequency had already been determined to be at a vernier setting of
132.5, then the op would set the vernier to 132.5, not try to use the
frequency display to "locate" 6003kc.
Ray, W2EC
Glen Zook wrote:
> The accuracy and stability of the receivers of the
> World War II era are really not that bad. The
> bandwidth is fairly wide unless the crystal filters
> are "cranked in" so a little drifting wouldn't make
> that much difference.
>
> Also, the receivers were never turned off except when
> needing repair, thus were very stable. In addition,
> since the equipment was crystal controlled on the
> "other" end, it would have been very easy to have a
> crystal controlled oscillator on the receiving end to
> "calibrate" the receiver. Just turn on the frequency
> "standard", "zero beat" your receiver, turn off the
> standard, and wait for the scheduled transmission.
>
> Glen, K9STH
>
>
> --- Philip Atchley <[email protected]> wrote:
>
> How did "intercept ops" accurately set their receivers
> for expected incoming messages?
>
> =====
> Glen, K9STH
>
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