[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

help hearing LEO sats?

I'm looking for some advice on what a "good" satellite would be for 
just receiving.  Here's some background:

For the past two or three years I've worked on my thesis research on 
and off as I took my MS EE classes part time (I'm full-time staff at 
the university).  For my thesis project, I'm trying to set up a 
"real-time" data source for a Digital Comm lab.  The current hardware 
in the lab does bit error rate (BER) measurements, lets you adjust 
attenuation, noise sources, and such things, but all on a preset data 
stream so that the BER can be counted.  It would be great to be able 
to also do that with real data, and instead of seeing BER 
measurements, see what happens to the real-time text.  For class we 
might end up using recorded data, but we'd like the option of live 
data if the orbit was at the right time.

I started out with a 1/4 wave 70cm groundplane on the end of an older 
piece of hardline on the roof (4 stories) of the EE building, with an 
HF receiver, mixing the signal down from the 70cm range with lab 
equipment, trying to hear AO-16. no luck. I finally found the 
reference that said to use the secondary frequency, still no luck but 
only one or two tries. By then I had to tear down for the semester. 
We got some funding and got some IC-R9000 receivers, and two towers 
one has a log periodic and an omni-directional antenna, the other 
with an Az-El rotors and S-band and 70cm beams and new feedline and 
some mast-mounted preamps.  The omni and log periodic are both 
tested, the other antennas and the Az-El rotors haven't been tested 
out yet.

I decided I should try an listen for something with a beacon, instead 
of just a transponder (since I wasn't sure that anything would be 
transmitting while in my area otherwise).  I ended up picking UO-11 
until I found something that referred to the beacon only operating 
some days, then I tried to do some serious research on what would be 
a good satellite, picked WO-18 only to have it go off the air. (I'm 
now carefully reading the ADN status reports before I try anything!)

So, with all that, what do people suggest?  The location is in 
Urbana, IL USA. the closest city in most of the databases is 
Champaign, IL which starts about 3 meters from the building I'm 
working in, although the lat/long listed for Champaign is from the 
airport, which is a little further away, but less than 10 miles.

I could probably set up a 2m FM uplink somehow if it is easier to use 
a transponder (for this part, not for the class). For the moment, I'm 
just trying to hear data signals (I've a decent idea what 1200 bps 
and 9600 bps signals sound like) by ear.  I'm also setting up a PC to 
eventually run the Az-El rotors and tune the receiver, but I'm still 
just getting started on that.  I just need to prove I can hear a 
satellite at this point!

Long term we'll have the BPSK/AX.25 software going as well, hopefully 
on our new Erithacus DSP-based lab boards that are accessed via 
Telnet and MatLab for the user interface. (These boards are pretty 
neat, for those interested, it was developed here by another student, 
Jake Janovetz, info at 

Thanks in advance for all ideas and advice,


debbie, N9DN (formerly KA9JYI)

Debbie Fligor, n9dn           Network Designer/Engineer, CCSO, Univ. of Il
email: fligor@uiuc.edu          <http://www.uiuc.edu/ph/www/fligor>
"Every keystroke can be monitored. And the computers never forget."

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org