[CQ-Contest] Reciprocity in signal strength

[Chuck Dietz]

I have occasionally observed times on 10 and 6 meters when signals seem
much stronger in one direction than the other. This is measurable to some
extent by the signal reports on FT8. It usually corrects after a half hour
or so. Sometimes it repeats the same pattern at the same time the next day.
The only plausible explanation I have heard is “tilt in the ionosphere.

Chuck W5PR

On Mon, Jan 23, 2023 at 6:39 AM K9MA <k9ma at sdellington.us> wrote:

> On 1/22/2023 1:11 PM, Jim Brown wrote:
> > Yes, I've long been convinced that many (most?( instances assigned to
> > "one way propagation" are really differences in RX noise, or of
> > propagation from directions on the other end of the QSO that are
> > stronger than other than mine. One example is a few hours after the
> > start of 160M contests, when I'm hearing bigger east coast stations
> > plenty well enough to copy, but they don't hear me. Yes, directional
> > RX antennas on both ends is a factor, but because the band is open to
> > the east for them, they have both signals and noise propagated from
> > the east.
>
> A similar thing happens trying to work EU from W9 on 80 just after our
> sunset: We hear the EU stations just fine, but they are hearing a
> horrendous din coming from everywhere in EU and to east. It's really
> hard to get through that, especially in CQWW. Similarly, when Jim is
> hearing the east coast at the beginning of the 160 contest, they are
> hearing lots of much louder stations from eastern NA.
>
> 73,
>
> Scott K9MA
>
> --
> Scott  K9MA
>
> k9ma at sdellington.us
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