RR, thanks. Can you say something about the noise (QRM/QRN) situation
relative to the recent test at 2970 Hz? Assuming equal noise conditions,
the signal could be 3 dB weaker for a message decode. And i calculated a
3 dB weaker signal ( G = 40 * lg(2470/2970) = -3.2 dB).
I remember Jims plot from the email of the 7th, June 2017, attached. Two
markers, showing the consideration that a lower frequency could work
even better than 2.47 kHz on our path? But it's not the best time in the
year to try :-)
Fortunately the SNR is well at IK1QFK. That gives an impression of what
can be expected in ~ 450 km distance.
For a next test at lower frequencies i better concentrate on carrier
transmissions again.
Hmm, looking at that plot, i see that 970 Hz could work 40 dB better
than 2.47 kHz. The plot is based on a constant ERP i guess. At 970 Hz
the signal should be 20 dB weaker than at 2970 Hz, assuming equal
antenna current and equal skin depth (loop size). Maybe we find an
advantage, a higher loop size at that frequency. But even with 20 dB
less ERP the signal would be better detectable than at 2970 Hz?? Or do i
misunderstand something here? If not, then it is worth a try!!! That
would be dreaming^4.
Ideas?
73, Stefan
Am 18.04.2019 10:15, schrieb Paul Nicholson:
Nothing decoded in Todmorden.
> it is 'CFM'.
No significant correlation either, best carrier Eb/N0 -9.6dB.
--
Paul Nicholson
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FDTD Plot , updated, (E field), by Jim_2.jpg
Description: JPEG image
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