[Scan-DC] 137-138 MHz satellites?

[Andrew Clegg]

I've been recording some waterfall plots of the 137 - 138 MHz satellite 
downlink band with my HP spectrum analyzer today. I looked back through the 
data recorded while I was at work, and it appears I caught several 
narrowband signals throughout the band, and one relatively strong broadband 
signal near the top of the band. This is just with a discone, and without 
any pre-amp, so the signals must be fairly strong (for satellites) to show 
up directly on the specan, given the lousy noise figure. The signals come 
and go consistent with the ~few minute pass of a LEO satellite, so I believe 
they are real, although I can't yet be certain. They should be easily heard 
on my receiver, or even a regular scanner with a decent antenna.

I suspect the narrowband signals are Orbcomm. Does anyone have any current 
active downlink frequencies for that sytem? The waterfall plot resolution is 
not quite good enough to assign a reliable frequency to the signals. I'd 
like to try to record their sounds. Online references all seem to be quite 
old. The approximate frequencies I captured are:

137.244
137.311
137.379
137.404
137.450
137.502
137.726
137.731
137.750

These are all +/- few kHz due to the resolution of the plots. The 137.726 & 
137.731 signals could be one in the same.

Does anyone know of any other confirmed active satellites in this band 
besides Orbcomm, and their freqs? Any idea what the broadband satellite 
might have been? Based on the data, it looks like two peaks, each of  ~25 - 
40 kHz wide, one centered ~ 137.94, and the other ~137.98. It was visible 
from ~11:42 AM - 11:45 AM, with a definite peak amplitude ~11:44 AM (all 
EDT, from Arlington VA), and then quite a bit weaker ~11:55 - 11:58 AM. It's 
possible that this was an overhead pass, and my antenna, which has better 
gain toward the horizon than straight up, caught the signal best when rising 
and setting. A similar signal was seen again, but much weaker, around 12:59 
PM, which would be too soon to be the same satellite passing again. Those 
were the only broadband "passes" from 8 am to 3 pm. (Then again, this could 
be something other than a satellite, but the allocation for this band is all 
satellite downlinks).

Any specific frequency info on currently active satellites in this band 
would be appreciated!

Cheers,
Andy