[amsat-bb] Re: AO-16 reconfigured.

Alan ve4yz at mts.net
Tue Jan 22 13:29:16 PST 2008

Magnificent effort...   monitored the downlink on the 21:20Z pass over EN19.
Seemed to get best reception on USB downlink.  When it was well into the
Cold Great White North and the traffic quieted down I tried to hear myself
and it may take a couple more passes to get SatPC32 TX/RX splits right on.

Thanks to the AO-16 team on a job well done.

73, Alan VE4YZ


-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Andrew Glasbrenner
Sent: January 22, 2008 12:48 PM
To: pacops at amsat.org; amsat-bb at amsat.org
Cc: amsat-florida at amsat.org; ans-editor
Subject: [amsat-bb] AO-16 reconfigured.

Since AO-16 was recovered approximately 6 months ago, the command team has
attempted to reload the satellite software almost a dozen times without
success. Subsequently a series of memory tests were performed which points
towards a hardware failure which prevents restarting the spacecraft software
successfully. This team included Bruce Rahn WB9ANQ and Jim White WD0E
advising Mark Hammond N8MH as the primary groundstation. Mark put in many
early hours during the multiple reloads and test sessions, with Bruce, Jim,
and others advising. Thank you to all involved for your hard work.

After the conclusion that the spacecraft computer system was damaged and as
discussions about decommissioning were taking place, Jim recalled a series
of low level commands included in the spacecraft design by Tom Clark, K3IO
during construction. One of these commands allows an uplink receiver to be
directly tied to a downlink transmitter. The twist is that the uplink is
regular FM but the downlink via the BPSK transmitter is DSB (Double
Sideband). Mark placed the satellite in this mode early this week and some
testing was undertaken. The satellite hears VERY well, and the reduced
bandwidth by using either USB or LSB on the groundstation receiver allows
for a very robust downlink. Tuning the downlink is just like on a linear
transponder, meaning it is tight and with fast Doppler. Uplink tuning is not
required, just as with the FM mode V/U satellites. QSOs were made between
N8MH, WD4ASW, KO4MA, K5QXJ, and WA6FWF. My personal observations include
being able to access and hear the satellite within one degree of the
horizon, much lower than any other current bird for my QTH. This should be
an easy satellite with omni antennas and a 70cm preamp.

With that explanation, I'm happy to open the satellite to general use on
voice for a test period. Please submit reports either to the -bb or to
ao16 at amsat.org . The uplink is 145.920 FM, and the downlink is 437.026 SSB 
+/- Doppler shift. Please restrict your uplink power to a reasonable 
and do not transmit without being able to hear the downlink. All the general
single-channel guidelines apply. Enjoy this bird's new life!

73, Drew KO4MA
AMSAT-NA VP Operations 

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