[amsat-bb] 1.2 GHz and 2.4 GHz Birds
k9qho6762 at sbcglobal.net
Fri Aug 28 00:45:42 UTC 2015
Sat Name: DTUsat-2, Beacon is 200mW, Object 40030, 2401.842 MHz. Signalsare very strong, and do not fade. Easily copied with a single
helix. It's a good signal to test tracking on 2.4 GHz.
Battery power has failed. Downlink only during ellipse using power from
solar panels. DTUsat-2 appears at all locations either once or twice at
about 11 AM local time and again about midnight. It is sun synchronous.
The CW beacons can be every 30 seconds apart or one minute apart depending
if the on board computer (OBC) is running. If the OBC is running, the
first three bits following the CW I.D. will be "dash-dot-dot" or 100.
If the three bits following the I.D is "dot-dot-dot" or 000, the OBC is
powered but not running.
When the OBC is running, CW beacons may be 1 minute apart with a tone
sounding mid way between beacon intervals. Downlink may be a full CW
beacon, partial CW beacon, a tone, or a missingsignal for that interval.
The beacon CW coded message following the I.D ( OZ2DTU) is broken into five segmentswhich is STATUS, Radio Temp, Battery Temp, Battery Voltage, and Beacon
Count. Beacon count, the last segment, is the "number of beacons since
the last full system reboot". This number can be a "dot" which is zero up
to a large number, for Example: "Dash Dash Dot Dot Dash" which is 25.
To me, a good condition would be a Status of 100 with a Beacon Count 30.Doppler is 100 KHz over the entire pass. Current Keps and accurate computer clock is necessary for good tracking.I've been recording audio for about 3 months for DT University. It's a good signal to track. Google DTUsat-2.
73, Mike (K9QHO)
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