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Roger, I have written to James (Duffy) direcly and have given him the facts as I know them.
I can assure you that the information in the 1974 Amsat newsletter you refer to is *NOT* ... I repeat 'NOT' correct ... with reference to the timer.
Just because something "APPEARS" to be so, and Amsat "SAYS" it is so ... it doesn't necessarily turn that information into a 'FACT' Roger.
I have often been ... (and still am) ... in contact with Jan King and I prefer his version to the events re: the timer rather than those related in the 1974 journal ... not least since he actually built and installed that timer.
(Much has also been said re: Karl Meinzer's "filter" ... remember !!! technology has changed, those components are 31 years old !!!)
If you have a copy of the news sheet Roger, have a look at page 6 (quote) .... "accomplished by a crystal controlled clock" ... (unquote).
Without Jan's permission I will NOT retransmit parts of his personal mails to me on this bulletin board but if he assures me ... (and he does) ... that there was no crystal used in the timer ... I believe him. He also explained to me *WHY* it was thus.
I believe what was in the 1974 News Sheet may have been the plan !!! ... or the wishful thinking, if you will ... but according to the person who actually built and installed it ... "t'aint necessarily so!".
Like I have mentioned previously, in other mails, 98% of the data collected over the last 3 years is/was false data ... (GM1SXX wrote a special program just for this particular purpose) ... which, if you look more closely at it, (the data) it often contradicts itself ... but again, you will find references to this and the timer on the 'Observations" page at http://www.observations.biz/
(I have *NOT* published some of my findings on the Amsat-bb since they *could* be conscrued as criticism of Amsat ... (which is most certainly not !!! my intent) ... I have seen what happens to anyone who dare have the audacity to offer a different opinion to the majority... however, that being said ... what I have found can be read in various articles on the Observations site.
People will usually believe what they 'want' to believe Roger ... true or not ... and that's fine by me.
In part ... it's a free world.
73 John. [email protected] ........................................................................................................................................
From: "Roger Kolakowski" [email protected] To: "James Duffey" [email protected], [email protected] CC: [email protected], [email protected] Subject: Re: [amsat-bb] Re: AO-7 report.- Band switching Date: Sun, 5 Aug 2007 11:47:41 -0300
James Duffey queried...
"When AO-7 is powered all the time doesn't the on board housekeeping unit control the mode and switch between mode A and Mode
B?"
"The following information is from AMSAT NEWSLETTER dated Sept 1974
The two repeaters are operated alternately by means of a timer arrangement, but repeater selection and output power control can also be accomplished by ground command."
And . "from Jan King, W3GEY, who provided the following information in an email ...
It appears that the 24 hour clock that would cycle the transponders between modes A and B is working but, it gets reset every time the satellite goes into eclipse"
Which by my understanding, will produce a change of mode from A to B (or B to A if you prefer) every 24 hours with no eclipse event. I believe there have been cases where excessive power drain (usage) has resulted in a mode change mid-timer, but I haven't been able to document that.
Roger WA1KAT
----- Original Message ----- From: "James Duffey" [email protected] To: [email protected] Cc: [email protected]; [email protected] Sent: Sunday, August 05, 2007 11:32 AM Subject: [amsat-bb] Re: AO-7 report.
John - When AO-7 is powered all the time doesn't the on board housekeeping unit control the mode and switch between mode A and Mode B?
Having a full time Mode B LEO linear transponder is great, in my opinion, having a Mode A LEO one will be even better. - Duffey On Jul 31, 2007, at 5:32 AM, John Hackett wrote:
A study of the AO-7 eclipse charts for the last 3 years shows a progression toward non-elipse orbits in late 2007 - 2008.
In effect, this means that AO-7 in all probability will not change mode unless anything untoward happens.
It also means that we appear to have a permanent mode-B LEO linear transponder for the forseeable future ... providing operators follow the recommended operating proceedure.
Please *do* decrease your power as the satellite approaches TCA to avaoid FM'ing.
This not only helps the satellite, it helps the other operators in the passband.
Don't be fooled by propagation anomolies. The mode-B transponder is working well and will continue to do so providing the alligators go and play somewhere else. Under normal circumstances you do NOT !! need a lot of power. Please use only the necessary to maintain adequate communications. If you can't copy people adequately, you should improve your receiving capabilities rather than increasing your uplink power ... remember, aluminium is cheap and it's a lot more user friendly to everyone concerned .... with perhaps the exception of your neighbours.
For all intents and purposes, AO-7 is a QRP satellite. Please treat it as such.
73 John. [email protected]
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb