[amsat-bb] Re: AO-7 sleuthing

John Hackett archie.hackett at hotmail.com
Thu Oct 11 11:34:30 PDT 2007

Hello James,
                   A pleasure to meet you my friend.

Yes, AO-7 *can* be fully illuminated ... (depending on it's position and direction) ... before the ground-based "Greyline" prediction occurs at a particular QTH at AOS.

The opposite can also be true ... you're right !!!, celestial mechanics are very! interesting.

Mode-C is a QRP version of mode-B. Originally with 2 watts from the transponder but that was in 1974 !!!. One can only assume that after 31 years od space dust "decorating" the solar array this power would be rather optimistic ... but that is speculation because recently the old girl was! producing a bit of power in mode-B ... but a lot less in mode-A. Of course, nobody knows the *actual* power because there are so many variables with prediction software/power budget calculating software etc.

You mentioned radio astronomy ... I have the dubious distinction of being born within spitting distance of  JODRELL BANK, when I was a kid, the world's largest radio telescope
(and the first to command to Sputnik 2) ... so don't let the LA callsign fool you ... I'm a senile old Limey !!! ... ex: Signals c/o Her Majesty's Service ... and ex: NATO ... which is why I ended up on Frei Island, Norway.

I hope you don't mind me putting this on the Amsat-bb, I was asked particularly by several people on your side of the pond to keep "you lot" posted on developements.

My own "theory" is that two alligators several days ago "knocked" AO-7 into a mode-A/C switching sequence.

The "usual" mode-B winter/mode-A summer  switching has gone off track ... (I did warn about this several weeks back but got shot down). 

As I mentioned preiously, to fully understand AO-7's "case history" one needs to read all of it ... not just selected pieces. It's an interesting story ... and one I'm surprised Amsat have not taken more interest in since there are so many "firsts" for AO-7 and the old girl is *STILL* producing a few surprises.

Have a good day! Jim and thank you for your mail, a pleasure!.

73 John.   <la2qaa at amsat.org>   AO-7 Log Admin:


Homepage:   <http://www.observations.biz/>

> Date: Thu, 11 Oct 2007 14:11:20 -0400
> From: jhjipping at ameritech.net
> To: la2qaa at amsat.org
> Subject: AO-7 sleuthing
> John:
> You are quite a sleuth. And having fun at it.
> You have me interested in doing my own watching/listening.  A comment 
> and question.
> When the footprint crosses the grey line, the "footpint" is on the 
> ground, but Ao-7 is in orbit.  It is possible for the bird to be full 
> sunlight before it's footprint crosses the greyline.  Depending, of 
> course, it's dirrection of travel.  What do you think ???
> What is mode "C" ??  I know mode "A" and "B" but ======= "C" ??   I, too 
> worked AO-7 in the early days when she was but a youngster.  Not with 
> the same gear I have now,  but with lots of success and , now, fond memories
> By the way, your approach and activities in watching AO-7 reminds me of 
> what, I believe to be one of the most exiting science  ----  radio 
> astronomy.
> Jim Jipping, W8MRR
> AMSAT 5512 (small number , old geezer)

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