Satgen276  Satellite Profile No5 Amrad FM  by GM4IHJ          12th July 94
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Amrad Oscar 27 is the Mode J equivalent of RS14. It carries a commercial
payload plus an amateur radio single channel FM transponder. Uplink is on
145.850 MHz and downlink is on 436.800 MHZ plus or minus 10 kHz of doppler
So much of what was written about RS14 usage applies to this satellite.
Although Amrad does not as yet have a fixed operating schedule, so do not
expect it to be on regularly.
Amrad's uplink reception is very sensitive. You should never need to use
more than 25 watt EIRP. Indeed ,access via a hand talkie with a rubber
duck antenna is generally possible. By contrast however the downlink on
436.8 MHz is not so easy to receive. The doppler shift in a 14 minute in
range pass is fierce as it passes near your station. You need to listen on
the high side of 436.8 ( IHJ receiver best at 436.805 ) at the start of
the pass then 5 minutes into the pass you need to switch quite quickly
through 436.80 , then 436.795 and 436.790 before finally settling
somewhere near 436.785 towards the end of the pass.
Northern Temperate zone users should presently hear 10 successive orbits
with acquisitions spaced 100 minutes apart, from 0930 local sun time (
1030 local summer time ) to 0100 local sun time ( 0200 local summer time
). Orbit acquisitions get 27 minutes earlier each successive day, on this
Amrad track which at 99 degrees inclination ( passing west side of north
pole), is a mirror image of RS14's 82 degree inclination east side of
north pole track. Unfortunately this point means Amrad is less useful for
UK to North American contacts than RS14, because RS14 approaches UK from
America whereas Amrad approaches America from UK.
At present in July 94 the Amrad schedule is a bit of a mystery tour. The
satellite was on over the USA Field Day weekend but have not heard it
since ( although IHJ operating is at the mercy of a slightly more
important medical schedule at this time and I have yet to persuade the
medics to match their times to the satellite schedules). Equally
frustrating is the PIRATE QRM from both SPANISH speakers and LATVIAN ??
speakers. On orbits near Spain and the Canary islands there is continous
retransmission of a Spanish speaking non amateur YL using a pirate rig on
the 145.850 uplink. It is appreciated that this kind of QRM is on the
increase with Spanish taxi drivers also taking to 2m satellite uplinks.
Hopefully the authorities concerned will sort out this mess before 2m
uplinks and downlinks become useless.
Prior to using Amrad , IHJ reception on 435/436 MHz of signals uplinking
on 2ms has required the use of a 436 cavity filter in the downlink antenna
cable. As yet operation at IHJ on Amrad has all been done with this Mode J
filter against the 3rd harmonic of the uplink being permanently on line.
When Amrad next appears , a test with this filter out of circuit will be
tried to see if this problem which haunted Oscar 8J , Fuji Oscar 12 and
Fuji Oscar 20 , applies to Amrad. Hopefully , the Amrad controller will
shortly be able to publish a regular operating schedule , allowing lots of
experiments to be done on this excellent satellite. 73 de GM4IHJ @ GB7SAN