[amsat-bb] Re: DO-64

WILLIAMS MICHAEL k9qho6762 at sbcglobal.net
Sat Sep 13 07:47:04 PDT 2008

Lately, I have not been able to get a signal through DO-64. I hear the beacon but no transponder activity. To check on DO-64, go to http://oscar.dcarr.org/index.php .
I sent the Delfi team an email but got no response. I'll continue to try it when I'm in the shack and a pass occurs. When the transponder is on, activity is sparse. DO-64 is a challenge.
My impressions of DO-64:
Don't go spending a lot of money because of DO-64. When DO-64 was first released for amateur radio use, I was able the hear myself (CW) at very low elevation passes (<10 degs). My antennas are only 8 feet off the ground so I was shooting a signal through trees and buildings. When the sat got above 30 degrees, I was able to use the transponder for good CW QSOs. I think the transponder output is only 200mW. The circular polarity of the down link seems to be left hand in the north to south passes and right hand in the south to north passes. Since my down link antenna is LHCP, I can only work DO-64 in the morning ( north to south passes). The evening south to north RHCP passes across the US are currently not in the sun so the sat is off. I also notice down link signal strength is best on the first half of the pass then drops off in the last half. This makes it best to establish a QSO on the first half of the pass.
The beacon always seems to be there and always at good signal strength. The transponder will have signal strength above the beacon at times when I have a good signal path at good elevations. At that point, I can reduce my 847s output to about 2 watts and still hear my down link pretty well.
At this time, the transponder seems to be off. I will continue to try working DO-64. If I can help you any further, please email me.
All the best in your satellite quests.
Mike Williams K9QHO
AMSAT 33589

More information about the AMSAT-BB mailing list