[amsat-bb] Re: Oscar 51 packet baud rates

[Gould Smith]

Hello Patrick,

> I understand the ECHO BBS transmitter baud rate is 9600 or greater
For the U transmitters 9k6-38k4,  for the S transmitter 38k4-76k8  this has 
to do with the filtering required for the demodulation

> Can someone operate the more common 1200 baud up to echo and will it 
> appear as 1200 on the downlink and additionally, can this be accomplished 
> by ground control?
Theoretically yes you can get 1200 baud data though.  BUT, since it is a 
single channel, FM device, it would be difficult to get many entire packets 
through and locked in on the downlink side so much voice competition.  The 
satellite acts a cross band repeater, what goes in, comes out - including 
taxicab commuications.
The previous PL tone just gated the input audio into the transmitter.  The 
illegal signals were still being output from the reeiver, just not gated to 
the transmitter, so you heard noise.  I and many others prefer to hear the 
signals that the satellite is receiving, so I know it is working well and 
people don't tend to increase their output level to try to get into the 
satellite.

Operators can still receive the 9k6 telemetry from AO-51.  As Drew said the 
other day, we need some code changes to be made to allow another receiver to 
be used for the digital uplink for the BB, without causing the processor to 
have to respond to too many receiver interrupts from just noise.

73,
Gould, WA4SXM

----- Original Message ----- 
From: "Patrick McGrane" <N2OEQ at aceweb.com>
To: <amsat-bb at amsat.org>
Sent: Friday, April 13, 2007 5:13 PM
Subject: [amsat-bb] Oscar 51 packet baud rates


> Greetings again from Patrick, N2OEQ
>
> I understand the ECHO BBS transmitter baud rate is 9600 or greater.
>
> Can someone operate the more common 1200 baud up to echo and will it 
> appear as 1200 on the downlink and additionally, can this be accomplished 
> by ground control?
>
> Thanks for replies, 73, pat
>
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