Satgen 404  RS12KT Easy Sat Pt2  by GM4IHJ  (BID SGEN404)   21 Dec 96

The easily received and readable 145.91 to 145.95 Mhz downlink of
RS12KT offers two great advantages over other low earth orbit (LEO)
satellites such as RS10 , RS15 , Fo20 and Fo29.
 (i) It is a superb introduction for beginners to satellite reception
     and tracking.
 (ii) It is a first class guide to appreciating what is available on 
     RS12 ( and to a lesser extent RS10 and RS15), via sub horizon
     extended propagation by way of the ionosphere.
Both the above features are available on the RS12 29 Mhz downlink ,
but they are not as easy to use. Noting that the passage of the 10m
signal down through the ionosphere is subject to far more fading and
interference than is the 2m downlink.

This said , what can a complete beginner do with the 2m downlink?
First its clarity and strength make it easily receivable on basic
equipment. Then learning to tune USB and Morse signals in constantly
changing but not excessive doppler shift, is excellent training prior
to attempting to uplink signals and get qsos.

For the experienced satellite operator, the bonus offered by the KT 2m
downlink, is quite unique. In that it allows easy examination of the
full KT response band when looking for sub horizon DX and identifying
it clearly. But until the satellite comes above your horizon you
cannot hear the 2m downlink. So the trick at IHJ, is to listen on 10m
for RS12KTs 29.4081 Mhz beacon. If the beacon is heard when the sat is
sub horizon, then the full downlink band is tuned listening for DX. At
long range this preliminary beacon watch is assisted by running the
FFTDSP software to show the audio spectrum all around the beacon
frequency which removes the necessity to worry about beacon doppler
shift. In this way antipodeal beacon reception is possible quite
painlessly.

Then as the satellite rise above the station horizon , the 2m receiver
is used to patrol the satellites communications band, continuing to
look for DX. Noting that some of the best sub horizon DX often appears
when the satellite is above your horizon. Eg a recent incident where
RS12 was far away on the GM western horizon, placing the satellite
over Greenland, revealed a very surprising 7Q from Southern Africa
coming in 539, and there was the ever alert G3IOR already in
communication with him.

When eventually the satellite goes below your horizon , the switch is
made back to the 29 Mhz downlink, again augmented by a broad audio
FFTDSP watch. Often there is a break in signal for a few minutes at
LOS , but the signal may then return and be usable for up to 15 or 20
minutes. At which times keeping a note of sub satellite geography can
help with decyphering weak CW calls. But please remember when
transmitting to RS12KT that your 21.21 to 21.25 Mhz signal, is in a
band used by terrestrial stations , many of whom do not know that
satellites even exist. So always preface any call with CQ satellite or
CQ RS, so that terrestrial communications operators do not get too
mixed up.