[Fwd: LF: 136 kHz]
Wed, 31 Mar 1999 15:27:11 -0500
Peter Bobek wrote:
> 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?
> Donīt 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 werenīt. Your signal might be even some 30...40 db
> weaker over there even when radiating 31 watts ERP. Donīt 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)