Dear LF Group,
The Rugby TX is still off the air (or was at about 0730utc), as it
has been for the last couple of days. Worked G3XTZ, G3LDO, and
G3XDV last night, all 'armchair copy' signals. If anybody would like
a 73kHz or cross-band sked, please let me know - hopefully we will
be able to take advantage of this window of opportunity.
Also listened from time to time on 136kHz - but did not hear LA1K.
However, I dozed off some time around 2100, so might have
missed him!
OK about the Idea of experiments to compare big and small
antennas at a Decca site - this looks like an interesting idea, but
perhaps 1W ERP is being a bit hopeful from the small antenna; it
would probably be neccessary to settle for lower power from both
antennas for the duration of the experiment. I did some EZNEC
simulations a while ago, to follow up a suggestion by G3XDV that
the towers at Brookmans Park MF broadcast site might be acting
as parasitic radiators, enhancing the M0BMU signal. The result
was essentially that, with a spacing of some hundreds of metres,
the effect was neglegible, provided the big antenna was not
resonated at 136kHz. This could be achieved by grounding one
antenna whilst using the other, or similar.
A 300ft tower is still only lambda/24 at 136kHz, so should in theory
give the same vertical radiation pattern as an 'infinitesimal' vertical,
to all practical intents and purposes.
Hope to hear more about Decca sites soon,
Cheers, Jim Moritz
73 de M0BMU
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