[amsat-bb] Observations From Norway.
archie.hackett at hotmail.com
Tue Jan 15 03:25:59 PST 2008
Linear satellites are getting a bit thin on the ground lately arn't they - and what with the (hopefully) temporary demise of AO-51 (a software reload) there's not much a satellite operator can do other than to make an appearance on AO-7 or VO-52.
Therefore, I wrote the following 'missive' as a suggestion, so, instead of whinging, you can can get off your bum and chuck together a small interface for your FM handheld and try some QRP operating - you just might surprise yourself.
While predominantly aimed at European operators I added this to the amsat-bb because there are a *LOT* of potential 'linear' folks among the FM operators "over there".
Do please take the time to learn a little about power budgets and aerial gain etc.
73 John. <la2qaa at amsat.org>
OBSERVATIONS FROM NORWAY
14 January 2008
As many of us are aware, the average age of Hams is creeping up and satellite
operators are no exception - we're heading faster toward 'extinction' as opposed
The much debated 'no code' exam - (to encourage more younger amateurs) - has,
IMHO - had the complete opposite effect. With MSN and SMS why bother with
Amateur Radio? ... the answer would be ... to do something you *CAN'T* do on
your pet computer.
So what can be done to turn around the negative trend of this sad state of
affairs?. I don't pretend to have all the answers ... however ...
One possible solution is to attract more of the 'FM only' amateurs onto linear
satellites, to explore other means of communication so that they're not 'stuck'
with the boring 'single user' solution.
The usual fly in the ointment excuse, here is ... "but I haven't got any gear
capable of for example CW" ... which is of course an excuse that is as weak as
'hiss' with a capital P.
It is perfectly feasible to modulate an FM signal by switching on and off the
carrier ... some people have used the PTT button to achieve this but a more
elegant solution is to feed a controlled CW signal directly into the microphone
input of an FM ... A.K.A. MCW modulation.
Ahh! ... anti-social behaviour you say, sending 'FM' on a linear satellite - due
to the power budget, since FM is a 100% duty cycle mode ...
BUT !!! ... if one were to QRP by 25% as well as increase the aerial efficiency
by 25% - (or any permutation giving the same results) - one would *NOT* be
'hogging' any more of the available transponder power than one normally would on
a linear satellite.
Remember, the difference between a satellite signal at the horizon and at TCA (
time of closest approach) - is quite dramatic ... (not that many people bother
to regulate their power for ... "enough to do the job" ... or, as Bill used to
say ... "Tis' vain to do with more, that which can be done with less".
("Bill" = William of Occam 1347).
Regular users of AO-7 will be aware that while activity has increased this last
12 months in the afternoon and evening passes, the morning passes are still for
all intents and purposes devoid of any signal at all.
The increased use of AO-7 is most likely due to a lack of other 'linear'
satellites, VO-52's apparent lack of activity is most probably due to the low
orbit which results in an increased Doppler rate and smaller footprint. AO-7
does provide for 6500km footprints on a daily basis.
Due to above "waffling" ... I intend to conduct a few QRP FM experiments on the
mode-B morning passes. If you happen to hear an AO-7 'woodpecker' you might like
to try switching to FM for a moment to see if you can hear some CW.
As long as you keep your power low ... (LIMA - OSCAR - WHISKEY folks) ... QRP
PLEASE ... you signal won't be any more detrimental than a CW or SSB one. Of
course, you *WILL* have to take the bananas out of your ears and use them as
they were intended ... to listen !!!!!.
73 John. <la2qaa at amsat.org>
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