Well Mak, I use less than 50w EIRP so there's more to this than meets the eye.
I hope !!!!! I'm wrong when I remind you about the two stations I mentioned 14 days ago with their *EXTREME* power.
One thing's for sure, that kind of power is *NOT* good for AO-7 and could well have "knocked" the satellite into a mode-A/C switching period ... this *IS* possible.
You may remember I did warn a couple of months ago, when I first noticed the imminent changing of the transponder modes about what *could* happen with excessive power abuse.
I fear it has now happened ... though I sincerely hope I am wrong and it's just a passing phase ... (pardon the pun).
Time will tell.
73 John. la2qaa@amsdat.org
To: eu-amsat@yahoogroups.com From: sv1bsx@yahoo.gr Date: Thu, 11 Oct 2007 20:39:19 +0300 Subject: Re: [eu-amsat] The laws of physics.
...yes indeed gentlemen, it's a very interesting theme. I wonder also
several times about that.
Thomas, because I'm using NOVA for several years, the "Visible" is always
when the satellite is illuminated. Without light, how is possible to be
visible? Simply impossible.
Therefore, NOVA has 3 states:
1)Visible (illuminated Satellite)
2)Sun ( "" ""
3)Eclispe (NON illuminated Sat)
But I complete agree with: "if a satellite is sunlit or not has nothing to
do with greyline and sunlight/night on our Earth".
.. and I remember dozens evening & night's asceding passes of AO-7 from
East-South to North during last months,
where the AO-7 was over the dark side of planet's surface, but it was "ON".
However, NOVA always under this case wrote: "Visible" or "Sun".
***************************************************************
John,
about your note I have to say that:
definitely the latest behavior of AO-7 has to do with Grey-Line's crossing.
I agree. Just I diversify with your note about the crossing-timing
of footprint with Grey-Line. I think, the Satellite is "turned-ON" when is
about
1000-2000 Km behind of Greyline (over the dark area) and is mooving forward
to
the Daylight. At that time, a part of footprint is already into Daylight.
Today evening, I noticed about just the same.
Asceding orbit 50572, 15:55 Z -16:04 nothing heard. Probably was OFF.
At 16:05 Z I heard (suddenly) 2,3 signals on CW, but very weak.
I can't explain also this unusual, strange ECHO on Downlink-signals ! It's
always here,
when the Downlink signal is very weak.
(That remembers to me the "HF propagation", when the signal is received
from Short & Long path the same time !)
Another observation: it's obvious my Power is not enough anylonger for
accessing of AO-7.
I say that because, tonight even if I heard clear somebody to call CQCQ, it
was unable to access the Satellite with my 50 Watts ERP in order to answer
to him.
It's obvious that, AO-7 needs much more Uplink Power now.
Desensitization of AO-7's receiver ? Bad power-budget?
I don't know... I have no any comment here.
73, Mak SV1BSX
----- Original Message -----
From: "Thomas Frey" th.frey@tiscalinet.ch
Sent: Thursday, October 11, 2007 12:40
Subject: Re: [eu-amsat] The laws of physics.
John Hackett schrieb:
NB.
It's interesting to note that when the *footprint* crosses the grey
line ... (a phenomenon I've monitored for several days now) ... the
solar panels are in full illumination ... (theoretically !!!) ... but
the transponder appears to be OFF and switches ON just as the
footprint crosses the line.
A coincidence? ... I think not, but I don't have a "sensible"
explanation.
Explanations are invited to EU-Amsat.
73 John. la2qaa@amsat.org
Hello John
Where come the info from, that the solar panels are in full illumination ?
In general if a satellite is sunlit or not has nothing to do with
greyline and sunlight/night on our Earth. This is a widespreaded
mistake. I heard the 2m-beacon from AO-7 also in the night and it was
in full sunlight. I calculate eclipses with James' G3RUH's PLAN-13
software. You can find it here:
There are also programs, which calculates the "visibility" which
indicates, if the satellite is visible by eye. This has also nothing
to do with an illuminated satellite.
I hope, my explanations are correct. This is a very interesting theme
and I'm open for further discussions and corrections.
Mit freundlichen Grüssen, Regards, 73
Thomas Frey, HB9SKA
Thomas Frey, Holzgasse 2, CH-5242 Birr, Tel. + Fax: 056 444 93 41
http://home.datacomm.ch/th.frey/
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