David Gilbert wrote:
> The REAL Swiss Army knife for antenna modeling would, in my opinion,
> combine the terrain analysis of HFTA with the antenna modeling
> capability of NEC .... and do it for both transmit and receive. I
> remain convinced that, especially for low angle signals, asymmetric
> terrain that "looks different" to an outgoing signal than it does to an
> incoming signal can cause dramatically different signal levels on the
> two ends of a QSO even if all other considerations (power level,
> antennas, noise level, ground conditions, etc) are equal.
I don't know about that... That would imply a violation of reciprocity,
wouldn't it?
I would believe non-symmetric propagation via skywave, but not that the
"effective antenna pattern" is different for transmit/receive.
N6BV even
> alludes to that possibility in the ARRL Antenna Book discussion of
> HFTA. I've privately encouraged him ... begged is probably a more
> accurate description ... to write an arrival angle version of HFTA, and
> he indicated that if he ever decided to tackle such a task it would be
> sometime in the future. I fully understand that. It would be a totally
> different and probably much more complex problem since the incoming
> signal wouldn't be a point source like the outgoing signal is. Still,
> I'm desperately hoping he gives it a try some time.
>
> And of course there's always vertical polarization .... ;)
>
>
which makes the reflection calculations MUCH more complex (for
horizontal, it's much easier)
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