[amsat-bb] Interesting !!!.

John Hackett archie.hackett at hotmail.com
Thu Oct 11 11:08:48 PDT 2007

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 at amsdat.org>

To: eu-amsat at yahoogroups.com
From: sv1bsx at 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".



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 


1000-2000 Km behind of Greyline (over the dark area) and is mooving forward 


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 at tiscalinet.ch>

To: <eu-amsat at yahoogroups.com>

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 at 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:

> http://www.amsat.org/amsat/articles/g3ruh/111.html


> 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/





> Yahoo! Groups Links






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