[amsat-bb] AO-07

[Mvivona]

Thank you very much for the explanation Greg. 

Michael KC4ZVA
Sent from my iPad

On Oct 9, 2016, at 1:49 AM, Greg D <ko6th.greg at gmail.com> wrote:

Hi Michael,

It can't put out more than what it's capable of, and that's the key here. 

First of all, the term "full quieting" signal really only applies to FM
transmission.  But what you are saying is correct, that once the total
of all the uplink signals reaches a point where the corresponding total
downlink is "full", more uplink can't change that total. 

The point about "hogging" the transponder is that if one of the uplink
stations were to increase its power beyond that level, then to maintain
the downlink limit, the other stations get their share of the downlink
reduced.  And with AO-07, if you push it hard enough (not difficult to
do), the satellite will crash and reset.  The indication that the
satellite is running dangerously low on power is when the downlink
starts to sound watery ("FM-ing", they call it).  More uplink power in
this situation will only make things worse.

Greg  KO6TH


Mvivona via AMSAT-BB wrote:
> I know this has probably been explained before, but help me understand as this has always puzzled me. 
> 
> For example purposes I'm going to use 1 watt as the theoretical satellite's output and only one ground station on the input. 
> 
> The way I understand is: If AO-7 (or any other SSB repeater) receives a signal, it keys up the transmitter side and passes the audio through. If AO-7 transmitter is let's say a 1 watt, then a full quieting signal on the input should make the output max out at 1 watt. If the input signal is weak and noisy, then the output might only be 1/2 watt. 
> Please explain how the repeater's transmitter can put out more than 1 watt (using more power) if the ground station goes well beyond full quieting by uplinking with let's say 500watts. 
> 
> Thanks in advance for the explanation. 
> 
> Michael KC4ZVA
> Sent from my iPad
> 
> On Oct 8, 2016, at 7:11 PM, Jim Walls <jim at k6ccc.org> wrote:
> 
> My first guess would be that because AO-7 is functionally running with no 
> battery, if one station is running high power, it easily hogs all the power 
> available.
> 
> Jim
> K6CCC
> 
> 
> 
> 
> -------- Original Message --------
>> From: "Joe" <nss at mwt.net>
>> Sent: Friday, October 7, 2016 7:11 AM
>> To: "amsat-bb" <amsat-bb at amsat.org>
>> Subject: [amsat-bb] AO-07
>> 
>> I wonder if anyone has actually done any studies after all these years
>> on propagation's through this bird. AO-07
>> 
>> I find it in the past couple weeks soo interesting on how varied the
>> level of signal strengths can be on very similar passes.
>> 
>> Where one pass, vs another are almost identical, yet one will be full of
>> stations, and the next one all I hear is my own CQ.
>> 
>> BUT... that difference can be all made by just who is actually on the 
> air.
>> BUT.... then take two passes that are almost identical, and ignore all
>> the other people, and pay attention to just your own signal, where on
>> this pass my sig is soo weak that 90% of the time I'm hearing nothing,
>> then next pass that is very similar I am actually moving the S meter the
>> signal is sooo strong.
>> 
>> And in theroy, this is all Line Of Sight communications, the losses from
>> one pass vs another should be the same.
>> 
>> Yes polarity can be an issue, but I cant see it being the reason for the
>> whole pass duration.
>> 
>> Very Interesting!
>> 
>> Joe WB9SBD
>> --
>> Sig
>> The Original Rolling Ball Clock
>> Idle Tyme
>> Idle-Tyme.com
>> http://www.idle-tyme.com
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> _______________________________________________
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> _______________________________________________
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