Satgen 173   Satellite HF    by GM4IHJ                        18th July 92

The Radio Sport satellites continue to provide a good entry into satellite
operations for newcomers, and a wealth of experimental propagation data
for old hands.

RS12 normally operating Mode K 21MHz Up, 29 MHz down provides an excellent
communications relay for stations capable of 20 to 50 watts on the 15m
uplink, and 10m CW or USB reception on the 10m downlink. Any ordinary HF
antenna will do - dipole, beam or vertical, all give reasonable results.
Listen for RS12 beacon on 29.408 MHz.

RS10 is generally on Mode A 2m Up, and 10m down. It is accessible with 10
watts or so of CW or USB onto a simple 2m antenna, and the downlink can be
copied on any HF antenna feeding a receiver tuning around 29.36 MHz.
Listen for the beacon on 29,357 MHz.

By September long range HF propagation should start to return to the
Northern Hemisphere, but the Solar Flux levels are unlikely to match last
year. So we may have to wait until November to February 93 before we get
much sub horizon long range communications on RS12. Remember times for G
to ZL RS12 contacts seems to occur around 0500 0600 utc when sat is just
east of UK, and 1100 to 1300 ut when sat is north of ZL.

Several papers have recently appeared describing schemes to probe the
ionosphere and HF Universe. The one I found most interesting was a JPL
paper describing a proposed experiment to examine the HF Universe.
Recently we have had some tremendous results from satellites which opened
new windows of study of the Universe. IRAs the Infra Red sat found Comet
trails millions of miles in length and, detected other Suns which appear
to have material orbiting around them ( possible proto planets ? ). The
Gamma Ray Observatory has produced records which suggest some gamma ray
sources may be outside our Galaxy , and therefore of tremendous power. So
it is a pity that we have not yet done much at HF. As yet there is no
launch date for the JPL proposal, which envisages a group of low earth
orbit satellites each with a multichannel HF Rx . All sats report to earth
what they are receiving in each band and, exactly where the satellite is
in space ( GPS ?). The signals can then be correlated and used to
represent a long base line interferometer which will indicate where the
sources are in space. There will of course be problems. Similar single
band omni directional efforts by the Explorer satellites where badly
confused by Auroral Kilometric Radiation. At that time AKR was unknown
because it occurs above the Earth's ionosphere at frequencies which are
usually too low to penetrate the ionosphere and be heard on the ground.
Indeed even now we know very little about AKR - try looking at any
handbook on HF Radio - you will not find it mentioned although it is at
megawatt power at times, just above our heads.
So there is lots of room for satellites carrying HF experiments. We
allowed certain misguided individuals to shout down the efforts of the
builders of SARA, the Jupiter HF watcher. Lets try to see that does not
happen again. We should be doing more experiments to justify our licenses.
Not wasting time and frequencies talking for the most part about things of
zero consequence.  73 de GM4IHJ @ GB7SAN