On 5/18/22 8:34 AM, Joe Subich, W4TV wrote:
On 2022-05-18 10:51 AM, Kim Elmore wrote:
I'm pretty sure that there is no such data set in existence and I
don't know of a good way to collect one.
I expect there is sufficient data available from the WSPR folks
(WSPRnet) for WSPR or from the RBN for CW. While the signal
strength data is SNR and not purely dBm, in both cases you will
find a very well defined minimum SNR such that a 1 dB decrease
in signal level (or 1 dB increase in noise) will make the difference
between copy/response and "CQ in the face." 2 dB will *certainly*
make a significant difference.
The FT4/FT8 data from PSKReporter also includes signal (SNR) strength.
73,
... Joe, W4TV
The challenge with SNR data (as opposed to absolute levels) is that you
don't know whether the N is propagating over the same path as the S, or
different. A great propagation path doesn't help if you and the noise
being generated in your area propagate by the same path.
But you might be able to normalize it somehow. I spent the better part
of a year trying to come up with a good worldwide atmospheric noise
model, trying to merge lightning data, ITU curves, etc. - There just
aren't the public data sets readily available to figure it out. It
doesn't help that space observations are above the ionosphere, which
blocks a lot of the "interesting" frequencies for hams.
I've long maintained that the advantage of gain antennas (Yagis, 4
squares, etc) is more the ability to place a null (or other wise reduce
the strength) of interfering sources, whether natural or man-made.
Pointing the fairly wide beam of a Yagi off the great circle heading to
the desired other end reduces the desired signal, but reduces the
undesired signal even more, because the gain vs azimuth curve has an
increasingly steep slope as you move off the boresight.
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