James (et al),
Your measurement of DCF39 being 82 dB above the noise sounds about right. My
first measurement (65 dB here in PA) was with the miniwhip only 3 meters
above ground level – and with many fluorescent lights still on.
Albert PA0A measures 92 dB in 1 Hz and Roelof 85 dB.
I just measured DCF39 again, with the miniwhip at 11 meters, it is now about
78 dB above the noise (in 0,5 Hz). The improvement agrees with what I
already saw with Speclab.
But is still not as good as it could be. When I find the time I will drive a
copper rod into the ground. Will report on the outcome!
73’s
Minto pa3bca
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Ceterum censeo Carthaginem delendam esse
-----Original Message-----
From: James Moritz
Sent: Tuesday, August 09, 2011 23:58
To: [email protected]
Subject: LF: Re: HB9ASB... SNR of DCF39
Dear Stefan, Minto, LF Group,
No TX this evening here, I'm afraid, but I took the opportunity to make
rough measurements of the field strengths of G3KEV (12uV/m), DK7FC (1.9uV/m)
and HB9ASB (0.7uV/m) - see the attached screen capture.
As you can see, these are all "O" copy signals here. KEV is quite a strong
audible signal here as usual - DK7FC and HB9ASB look a bit weaker than they
actually were - this screenshot was taken with my loop oriented approx. N-S
to measure Mal's FS; with the loop oriented E-W Stefan and Toni were both
several dB stronger. The QRN level was fairly low here for the time of year,
and the band noise was dominated by Loran C with the loop aimed N-S, and
sidebands from DCF39 with the loop E-W.
Earlier, I repeated PA3BCA's signal-to-noise measurement on DCF39 - The SNR
of DCF39 was about 82dB with the 0.5Hz FFT noise bandwidth. My location
IO91vr is a bit further from DCF39, so I would expect the SNR in PA to be a
few dB higher under similar conditions. The field strength of DCF39 was
about 3mV/m (several dB higher than the daytime level I have measured in the
past), making the noise floor about 0.24uV/m in 0.5Hz.
Cheers, Jim Moritz
73 de M0BMU
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