Amsat OSCAR-51: Unusual mode:

Iain McFadyen mcfadyenusa at
Fri Nov 3 18:15:34 CST 2006

I just wanted to bring to your attention that the AO-51 (a.k.a. ECHO)
satellite is in an interesting, but somewhat unusual, experimental mode at the

Uplink on 145.880 (-/+ doppler), USB.
Downlink on 435.300 (+/- doppler), FM.
Downlink is in HIGH POWER mode. 

There is a nearly overhead pass, starting at 19:57EST this evening (Friday)
for Northern VA.

* At 19:57, AO-51 will appear over the horizon 
   at an azimuth of 156 degrees true.

* It will climb in the sky, changing very little in azimuth, but rising to
almost overhead at 20:05.(AO-51 max elevation will be 60degrees, on an azimuth
of 081degrees true, at 20:05)

* It will then descend from being overhead, and disappear over the horizon at
20:12, on an azimuth of 352degrees true).

Start out with your FM receiver tuned to 435.307 or thereabouts. Leave your
receiver tuned there till almost 20:05. Then tune down to 435.293 after the
satellite has passed overhead. 

(Many FM receivers will be set up for 5. 12.5 or 25 khz channel spacing. If
you can use a multimode receiver, set it up so that you are using fine tuning
steps (100Hz for example) but set to FM mode, so that you can track the signal
down as the satellite flies overhead. A center frequency meter is very helpful
for this!)

If you can't get your Rx into fine tuning mode, you may have to make do with
tuning to 435.305 for the first few minutes, moving to 435.300 for the high
elevation part of the pass, and then tune to 435.295 on the downside.

Though they are not so high in the sky, there are more passes tomorrow,
(Saturday). The higher passes start at 09:45, 19:19, and 20:57.

If anyone wants any more specific information, just drop me a note.

I believe this mode will stay in place till mid evening on Sunday, when it
will be reconfigured to a different mode. 

Iain    KI4HLV

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