From Steve
Thanks to the many who replied directly to me re my comments. I am
encouraged that there is a 'silent majority' out there who share the same
sentiments.
You would be suprised on just how many! Thanks for the light relief.
Older LF Receivers.
While at Amberley museum, a few weeks ago, I came across a Marconi
receiver, the CR200. It covers from about 15 to 500kHz in 4 bands so
I asked if I could borrow it to see how it shaped up to modern receivers.
The main difference between it and other receivers, apart from being
an LF receiver, is that it appears to be a TRF receiver, not a
superhet (no IF stages or cans).
It worked first time in spite of probably not having been switched on
for umpteen years. It is very sensitive with a wide range RF gain
control and a preset! LF gain control. I could hear the stronger
stations on 136kHz without any trouble.
While in QSO with M0BMU on 73kHz a couple of nights ago (Jim's signal
was 559) I asked if he would stand by while I tested this receiver
with his signal. When I switched from the TS850 to the CR200 I lost
him competely - the problem was from the Decca signals down the band.
So it would seem that the skirt selectivity of the filter was nowhere
near as good as the TS850.
Perhaps the CR200 was not designed for communications as such; it has
a multi-way socket on the front panel labelled 'DF'.
I will be returning the CR200 back to the museum on Friday and hope
that my hernia is better by the time I go on vacation.
--
Regards, Peter, G3LDO
<[email protected]>
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