Hello Jaap, hello all,
transmitting with high efficiency is very important but more important -
like on the other bands - is the capability to hear others calling.
A very tall antenna does not only pick up a lot of static but
is also often useless for low noise reception... You might
have picked up a lot of LORAN noise as well.
The frequency you mentioned for SCW 136.495 is not among those recommended
for SCW. Most of us are using the wide window
above 137,600 kHz. 3 sec dot lengths might be adequate for
SCW in your case. Early morning or early afternoon is a good
time to give it a try. Do kites also fly well at night?
Don´t expect to damage the S-meters on the other side of the pond. A few
enthusiastic US-boys just returned home from an
expedition to see if they can hear EU BC- (and Amateur-) signals.
500...1000 kW from almost quarterwave verticals
were audible - others weren´t. Your signal might be even some 30...40 db
weaker over there even when radiating 31 watts ERP. Don´t be disappointed!
It could happen, yeah! But the
comments above are probably more realistic. Europe is within
your reach. Try to catch the "poor EU-lowfers" struggling with
efficiencies in the order of close to 1 percent (at maximum).
During the RSGB-HF-Convention (fall 1998) we set up the following
recommendation (using the frequencies listed below):
136,458 (+/- 3 Hz), the LORAN-free window is only 6 Hz wide.
137,600-137,800 (most of the activity is between 137,650-
137,750 kHz).
From recent examinations at a friends place close-by I can only recommend
the use of an attenuator (switchable in 5 db- steps) between such a tall
antenna and the RX-input to check overloading of the RX. Quite a few of us
have to do this - including me (I have about 1,5...2 volts RF across 50 Ohm
RX-input from LF-transmitters 25 and 45 km away!). Unfortuna-
tely their tx-frequencies are too close to our band to use sharp
cutoff-filters. A solution might be a narrow crystal filter at the front
(RF) end.
I hope you and the crew are not too frustrated reading my mail. PLEASE DO
CONTINUE with your seaside experiments! We
really appreciate them! There are many who still need a
QSO with PA-land! Try to hear our whispering...
Kind regards,
Peter / DJ8WL (ex DA0LF, first German LF-lis)
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