[NLRS] UHF Contest Propagation - need your help

[Dr. Gerald N. Johnson]

On Thu, 2009-09-03 at 12:18 -0500, Richard Clem wrote:
> 
> I don't think this was propagation related, since it was basically LOS, but
> since you asked, I'll put it out there as another data point!
> 
> In the June contest, it was a very easy QSO from the Ridgeway site to W0AUS on
> 222 FM, using a handheld.  In fact, I think we made our 432 contact from there
> on FM using a handheld.  I think I also made easy QSO's from handhelds from a
> lower location on the other side of the freeway in EN34.
> 
> But in the August contest, I just barely made the contact using the same rig,
> and my wife wasn't able to make it at all.
> 
> I suspect the W0AUS antenna was pointing the wrong direction or something.  I
> can't think of any reason why it would be a propagation issue, since it is
> pretty much line of sight.  But I was surprised that the contact was so
> difficult, since it had been so easy in June.  In June, they had been full
> quieting as soon as I turned my rig on.  In August, I had difficulty copying
> them, and had to repeat my exchange several times as I walked around looking
> for a "sweet spot".
> 
> This was Sunday morning.  If you need an exact time, I should be able to find
> it in my log.
> 
> 73,
> Rick W0IS
> 
> 
I operate 2m packet over a 40 mile hop. Just barely not line of site,
but generally workable with a bit of power on FM. The receive signal
here varies from S-3 to full scale on the FT-726 S-meter (very generous
on FM, about 3 dB per S-unit and 5 dB for each 10 dB over S-9 on the
scale). Propagation can vary that much due to differences in refraction
(best of a calm clear early morning when radiant cooling of the earth's
surface has made a temperature inversion, and worst with a wind that
prevents any stratification of the lower atmosphere) and differences in
multipath reflections that can change drastically from moving your
antenna a quarter wavelength in any direction.

73, Jerry, K0CQ