[MRCA] 29.4 ID

[Rich Arland]

I was going to suggest this AO-7 connection earlier as I have been loosely following this thread. Having done a LOT of LEO satcom  work in the late 1980s-mid 1990s, I tend to agree that this might be the CW beacon on AO-7.


I haven't listened but if there is some Doppler shift on the signal I would say that it is very likely to be AO-7. The Mode A downlink (29MHz) won't have much Doppler shift but it will be noticeable. The 2M and 70CMs downlinks will have a lot of Doppler shift.


Just sayin'.


The AMSAT site has all the info on AO-7 as some folks are still able to work thru that bird. A sure give away would be to match up the AO-7 orbits with the date/time the "ghost ID" was heard at YOUR location. Not a daunting task as there are several good free sat trac programs out there and at last look the AMSAT site has the ability to generate a set of pass data using their program on the site.


Hope this helps.

vy 73

Rich K7SZ



________________________________
From: mrca-bounces at mailman.qth.net <mrca-bounces at mailman.qth.net> on behalf of Ray Fantini <RAFANTINI at salisbury.edu>
Sent: Monday, July 2, 2018 12:15 PM
To: scottpastor; B. Smith
Cc: mrca at mailman.qth.net
Subject: Re: [MRCA] 29.4 ID

Sounds like the ghost of A0-7 to me, launched back in 1974 its batteries failed in 1981 but around 2006 they opened up and when in direct sunlight A0-7 will sometimes come back on line. There were two on board transponders or modes (A and B) The mode A transponder is 145.85 to 145.95 uplink with a downlink of 29.4 to 29.5 with a beacon on 29.502 You would first locate the beacon and then tune down for traffic, that way you did not have to figure Doppler. Never corrected for Doppler on uplink just search in the pass band for your downlink.
The mode B side 432.125 to 432.175 uplink and 145.925 to 975 downlink and a beacon of  145.975 The satellite will operate only one mode at a time depending on what it wants to do when it wakes up and dies as soon as it goes into eclipse. The beacon ID is CW but I do not remember what they were.
Its in a high orbit and tends to be there a while unlike the low earth orbit stuff. Like most good ghost stories it’s always worth bringing up again.

Ray F/KA3EKH<http://www.qsl.net/donate.html>
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