|
Some more traces from Bob around 3 UT last night,
but somewhat worse than the night before:
The fieldstrength pattern of CFH 73.6 kHz seems
pretty much reproducible (when its's on). Levels at the same hour in
different nights seem to vary by no more than 3 dB or
so:
Bob, Loran-C is really not a problem here as the
spectrum predominantly consists of discrete sharp lines. Even with advanced
modulation schemes (Eurofix, eLoran), there's relatively little noise
emitted between the lines. To me, Loran is actually more of a blessing
because the lines provides a precise frequency reference. And it can be
used for detailed propagation monitoring as well: last night, the two traces
from Wildwood were again strong between 21:30 and 7 UT.
The 74 kHz noise here is mostly "made in Germany"
by the DCF77 time signal station, which is phase-modulated by a
645.833 bit/s pseudorandom sequence, repeating every second. The bad thing for
us is that this modulation is inverted with the disseminated timecode and
weather information, which spreads a significant part of the power between
the 1 Hz harmonics. Going down to say 72.4 kHz would probably improve things
here.
Best 73,
Markus (DF6NM)
Sent: Wednesday, October 23, 2013 2:58 PM
Subject: LF: CFH, 74.55 kHz
Last night some traces from Bob finally
appeared in Nuernberg, albeit a far cry from the excellent receptions of
Mike, Henny, Victor and Hartmut.
CFH 73.6 kHz dropped out before midnight but came back a few hours
later
Experimental Loran-C transmissions from Wildwood / Cape May are still
ongoing, strong enough to leave a weak daytime trace here.
Best 73,
Markus (DF6NM)
-----Ursprüngliche Mitteilung-----
Von: Markus Vester
<[email protected]>
An: rsgb_lf_group
<[email protected]>
Verschickt: Di, 22 Okt 2013 12:22
pm
Betreff: LF: CFH, Loran Wildwood
|
