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Re: SO-35 Over Europe



I have the 25-JUL-99 10:35 UTC pass of SO-35 over Europe on a digital disk.
Induced by the remarks of Richard, G3RWL, regarding the problems of the
Surrey Station accessing the satellite, I analyzed the record with the time
counter. From this I cannot confirm, that there was no way to suceed due to
congestion:

The duration of the pass was some 14 minutes. In the beginning there was
some data transmission, then there were a few QSOs of stations from
southern Germany, Austria, and Belgium. Then I transmitted the first time 5
min after my AOS for a test by saying my callsign shortly. (I am just
writing a new revision of our AMSAT-DL beginner's guide and wanted to
check, if it is worthwhile to recommend SO-35 as a bird to start with.)

After having said my callsign, I was called by an OE, then by a DG, and
finally by a HB9 station. I exchanged name, locator, and report with them;
one after the other and tried to keep the contacts a short as possible. The
avarage length of any QSO I was involved in was 35 seconds. (I reduced my
TX power after each QSO to check the minimum needed power, and endet at 1 W
into a Yagi.)

There were some 10 stations on SO-35 during this pass. I never called CQ or
QRZ. All in all I was called by 5 stations and I called 2 stations during
this pass. The total time of QSOs I was involved during the whole pass in,
sums up to about 4 minutes. In other words, in averageI took 2 minutes TX
time of the pass, i. e. 14 percent.

Many times during the pass Dirk, ON1DLL asked for QRX for the Surrey
station and called it. This QRX was always given by all stations, but there
was nothing but usual noise on the downlink during the breaks. There was
not a trace of a signal from Surrey. Additionally in the second half of the
pass a G station called and listened carefully more than a minute for
Surrey: Nothing in reply but unmodulated noise.

Because I only knew the announcement of the Surrey activity for Saturday, I
then was convinced, that there was no station QRV from Surrey. If the
station in Surrey was not able to access SO-35 that pass, this is not to
blame to the satellite nor to the other stations using it, that's for
shure.

However, I think everybody should keep in mind: The SO-35 FM transponder
obviously works great, but one FM channel on a satellite, which comes 7
times a day for a few minutes (and in the case of SO-35 only twice up to
now), will not provide enough communications capability for all stations,
which are interested to work it. This is mainly not due to operating
practice, but to physical constraints. The Sunday pass over Europe was an
exception, as there were only 10 stations on (due to lack of publicity),
and there were lots of gaps in between the QSOs. These conditions have to
be regarded as exceptionally favourable!

73 de Norbert, DF5DP
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