[amsat-bb] Re: Is it 100% impossible to work a satellite below thehorizon?

i8cvs domenico.i8cvs at tin.it
Sun Mar 13 10:27:31 PDT 2011

Hi Bill, NZ5N

When AO40 was alive and well I experimented many QSO's with several
stations in USA when the elevation of AO40 for me in JN70ES was already
-2 or -3 degrees belove my free horizon using InstantTrack for tracking

The AO40 downlinh was obviously in 2401.300 MHz but my uplink was in
70 cm or 23 cm and my negative elevation was monitored by those stations in
USA using all the same set of keplerian elements but with different tracking
programs and all gives the same results that the elevation for me was

To explain this uncommon below the horizon propagation anomaly I believe
that is my QTH location that play an important rule because my building is
located only 100 meters from the beach and the antennas are  50 meters above
the sea level and so it is possible that propably in presence  of
particular temperature and humidity and pressure conditions a duct similar
to a wave guide is developed over the sea so that my signals and the
satellite signals are traveling into the duct for many miles allowing the
QSO to be made with AO40 belove my horizon.

Another station i8KCL in my QTH wich home is many undred meters behind my
back and more high them me over the sea level he was never able to receive
AO40 with -2 or -3 degrees belove the horizon or made a two way QSO with the
above negative elevation because probably owing of his home altitude he was
not in condition to enter his signals into the suspected duct.

I do not remember the call letter of the many stations in USA experimenting
with me the above propagation anomaly but if some of them are reading this
AMSAT-BB please drop a line in responce.

Best 73" de

i8CVS Domenico

----- Original Message -----
From: "Bill Dzurilla" <billdz.geo at yahoo.com>
To: <amsat-bb at amsat.org>
Sent: Sunday, March 13, 2011 1:25 AM
Subject: [amsat-bb] Is it 100% impossible to work a satellite below

> I was giving a presentation at our club meeting called Working DX on the
Satellites and afterwards someone had a good question: is it at all possible
that tropo, skip, or other form of enhanced propagation can enable a contact
via a satellite below the horizon?
> It has never happened to me.  Has it ever happened?
> 73, Bill NZ5N
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