[NLRS] 10 ghz scatter!!???

[Mike King - KM0T]

Hi all,

Gene, N0DQS and I were testing all the bands tonight in preperation for the
UHF contest.  We spent a considerble amount of time ragchewing on 10 and 5.7
ghz just to get a feel again for how it all was operating.

Gene was in EN22GE, about 73 miles away.  Signals were 5x9+10 to 30 over on
10 ghz and slightly lower on 5.7.  This was holding up very well over the
course of an hour or so as we ran the other bands, so we kept going back to
10 and 5.7 to see how conditions were changing.

Anyway, I started to screw around with my elevation control and while we
were on heading with each other, I started to point the dish at the ground.
We still copied each other well when my dish was pointed 45 degrees below
horizon.  So after that, I decided to point the dish up.  I have the rotor
setup so I can point straight up in the air so I can park the dishes durning
windy conditions.

Well, we copied each other all the way up, even when my dish was pointed
straight up.  Scratching our heads led me to say, "well, if the dish is
pointed straight up, then I should be able to rotate any direction in
Azmuith"

I proceeded to rotate around the clock and copy was still managable all the
way, thus proving that the dish was straight up.  Not believing this myself,
I went outside to check the tower.  Yes indeed, the dish was pointed
straight up.

We tried 5.7 ghz and experienced the same thing!  Even with 250 milliwatts
on that band.

The next step was to rotate the antennas back down to the horizon and start
swinging my dishes around.  Well that led us to hearing each other almost
all the way around the clock.  The strongest was when I was pointed directly
away from him (other than direct dish heading)  We also heard each other on
5.7 ghz with the 180 degree dish heading away from him.

The best I can figure is that there must have been an inversion up high and
that was scattering the signal.  It was 66 degrees here tonight when it
happened (about 0400utc) from an 85 degree high.  Humidity was not that high
here today, pretty comfortable day, one of the nicest of the summer.

Anyway, when I got pointed back on him directly and on horizon, the sigs
jumped up to 30 over, so I know I was on the right IF and 10 ghz band!  So
Gene then did the same thing on his side and sure enought, about the same
was repeatable on his end, the band appeared to be fading abit by that time.
Direct heading sigs where then 5x9 on both bands.  Which may account for not
as good sigs when he was pointed straight up.  (he has az and el control on
his dishes as well.)

One note, while I was pointed straight up with Gene coping me no problem, he
rotated off the beam heading and lost me right away, so it looks that at
least one of us has to point at the other.

So, from now on, I will just point my dish straight up and not worry about
the dish heading.  I will let the rest of you worry about it :)

Seriously, we will try it again tommorow, my guess is that it will not be
repeatable when it warms up.

So, any thoughts?  We sure had a good time giving the equipment a workout.
As for drift, pretty much non-exisitant.  I think with the cooler wx
ambient, that may be a factor.  The drifting we experienced weeks ago when
we all worked, it was hotter than you know what!

73
Mike - KM0T en13vc