Unless you are working full duplex and you can hear your own downlink, you will not hear a peep on SO-50 unless someone answers you. This is because, unlike the other FM birds, SO-50 does not transmit a carrier unless something is being transmitted. I assume this is done to save battery power. Try a weekend afternoon pass, when there usually are at least a couple of stations on.
I do not know for the life of me why they require the 74.4 hz tone to turn on the transpoder. They could use the normal 67 hz tone for triggering. I'm sure this is one reason why this bird is underused. Do we have any contacts with the support team to suggest a change?
This sat is not as strong as AO-51 but I've worked it many times with just an HT and an Arrow antenna. But it can be frustrating without full duplex. You send the 74.4 hz burst and, since you don't hear a carrier, you don't know if you have failed to turn on the transponder or if you have and just no one else is around.
I wish something could be done to increase activity on SO-50.
73, Bill NZ5N
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I have worked every bird several times: AO7, AO16, AO27, AO51, FO29, VO52.
But I have never worked SO50. Tonight I had a pass DIRECTLY overhead. I tried the standard initiation call with 74.4 CTCSS, and then calling with 67 Hz. Never heard a thing. In fact, I don't think I have ever heard SO50.
I triple-checked the Doppler, turned down the squelch, turned up the RF gain. Not a peep. Even with only my Arrow yagi fixed at 30 degrees EL, I should have heard something. All I heard was the rush of static. I know this bird is lower orbit and smaller power out, but I should hear something, right?
I hope no one changes the tone requirement on SO-50. If you listen to AO-51 passes over the USA and compare it to an SO-50 pass you will know why - lack of QRM (as well as lack of users - but that's the same on most birds anyway).
SO-50 is similar to working simplex terrestrially, except that you hear your downlink. There is no constant carrier as in the other FM birds as you mentioned. That does make it more difficult to tune, however (and again, not knowing the history of this bird), I'm sure it conserves battery power and transmitter life. I will take a guess and say that the 'turn on' code actually turns on the primary receiver, which again would conserve it's life.
I rarely need to 'turn on' the transponder, even though I'm pretty much at the southernmost part of the USA. I frankly don't think it's a big deal to turn on a PL tone, if we are able to comprehend everything to make a satellite qso, then turning on a PL tone should be child's play.
However I must say, IMHO, SO-50 has the best audio of all the FM birds put together. It sounds like a local repeater to me. However it does appear to pretty much require selecting polarization. My system is circularly polarized, and this is the only bird that I can't work from AOS to LOS.
I also agree with you about wishing something could be done to increase activity on SO-50; but I won't limit that statement to just one of the birds we have available.
73 de W4AS Sebastian
On Nov 28, 2008, at 8:38 AM, Bill Dzurilla wrote:
Unless you are working full duplex and you can hear your own downlink, you will not hear a peep on SO-50 unless someone answers you. This is because, unlike the other FM birds, SO-50 does not transmit a carrier unless something is being transmitted. I assume this is done to save battery power. Try a weekend afternoon pass, when there usually are at least a couple of stations on.
I do not know for the life of me why they require the 74.4 hz tone to turn on the transpoder. They could use the normal 67 hz tone for triggering. I'm sure this is one reason why this bird is underused. Do we have any contacts with the support team to suggest a change?
This sat is not as strong as AO-51 but I've worked it many times with just an HT and an Arrow antenna. But it can be frustrating without full duplex. You send the 74.4 hz burst and, since you don't hear a carrier, you don't know if you have failed to turn on the transponder or if you have and just no one else is around.
I wish something could be done to increase activity on SO-50.
73, Bill NZ5N
Let me point something out here. The PL tone on SO-50 or AO-51 does not prevent QRM. It just makes it where you do not hear it. The offending signal is still present at the satellite receiver, and will still block you out if it is stronger than your signal.
Considering we have shut down several stateside Echolink nodes that thought 145.850 was a pretty good spot to operate, it's very important to have some means of monitoring the uplinks. PL does a fine job of saving power, which I suspect is it's primary purpose on SO-50, but it is actually detrimental to preventing QRM on the uplink. Fortunately we identified these guys via AO-27.
There are other effects of the PL that we have observed on AO-51 when several legitimate users are in competition for the uplink. When collisions occur, often none get through, and none of them know why because nothing gets repeated so the situation continues. With an open uplink, all stations can hear the logjam and hopefully enough stand down to unclog the uplink. This is why we stress the importance of full duplex operation.
The issue is moot with SO-50 anyways...AFAIK the satellite is primarily hardware driven. Considering it was an unexpected gift from the Saudis, let's not look in the horse's mouth too much.
A simple way to solve this is to use U/V instead of V/U for future FM satellites. SO-35 was a dream to operate, with a strong downlink easily heard, and an uplink that swept itself clean due to Doppler shift.
73, Drew KO4MA
participants (3)
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Andrew Glasbrenner -
Bill Dzurilla -
Sebastian