[amsat-bb] Recent AO-7 Activity

[Emily Clarke <w0eec@xxxxxxxxx>]

With UO-14 down AO-7 seems to be one bird that satellite users are using in 
greater numbers.  This morning there were 7 of us for the last (16:10z) 
pass over the US, which is probably nothing compared to the prime years of 
AO-7, but is quite a lot these days.

If you are using AO-7, please drop by the AO-7 Resource webpage and log 
your QSOs.  It would be greatly appreciated if we know how many successful 
QSOs are going on and in what modes.  You can visit the AO-7 Resource Site at

  [ http://www.experthams.net/ao7 ]

If you haven't used AO-7 before, there are a few tips that will help 
improve your user experience.  You can also find tips on the website.

1) Remember that AO-7 will arbitrarily start in one of two modes (A or B) 
and there is a slim chance it will come up in a third (Mode C - low 
power).   So if you are listening on one band, it may not be operating in 
that mode.
2) You may not hear the beacon, so listening for QSOs or  trying to find 
your own downlink signal in either of the two modes may be another way to 
determine what mode the satellite is in.
3) Please keep power to a minimum so that the transponder doesn't frequency 
modulate.  There are no batteries, so no voltage regulator.  FM is a very 
bad sign - not only does it cut down on intelligibility but it is stressful 
to the transponder. Ultimately it could lead to an early death (hihi - I 
guess the concept of an "early" death for AO-7 is a bit of a stretch.  But 
seriously stress could lead to failure that might otherwise be avoided.)
4) You may not hear other QSOs that are taking place, so even if you think 
you are the only person on the bird you should lower power if you hear your 
own downlink start to FM.
5) Noise is a definite problem on AO-7.  You may have to move your QSOs 
around the passband to avoid it.  It's a good idea to use a DSP, noise 
blanker and variable attenuator to lower the noise floor.

73,

Emily



W0EEC - CM87tm
ARRL - AMSAT - MSARC - ARCA
http://www.emilyshouse.com/W0EEC
http://www.experthams.net/ao7

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