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zero beat telemetry?



Hi All,

I am wondering how to capture accurate audio for telemetry (sputnik temp
etc.).  (NOTE: I am a beginner, I have not transmitted to a satellite other
than MIR yet.  I have been collecting info for over a year so far and have
been a member of AMSAT for just a little less than that.  I have read the
references available from amsat and participate and monitor this list daily
so I know what I am doing before I do it.)

Being a biological scientist, I have a great appreciation for controls and
standards.

I want to capture audio for decoding of telemetry.  My question is:
On a satellite where I cannot transmit a tone and find it on a downlink how
do I know that the tone I recieve is actually accurate or if I am not
capturing an audio tone that is erroneous.

I believe that possible sources of error can arise from:

1) My radio (FT-736R) frequency display not actually not what is injected
into the mixer...(if this is the case I guess I am out of luck!!)

2) The doppler correction I make is not the actual that is necessary and I
am tuning the rig improperly generating an audio tone that is not actually
that which is transmitted.

It seems to me that error source #1 is just something that I would need to
check and repair if necessary but, is error source #2 something that I can
control for?  Is there a control or standard tone transmitted by satellites
like sputnik 41 which does not change so I might use it as a "standard" for
tuning?

Also, are there other sources of error I have not considered?

Any help is greatly appreciated!!!

Thanks
KC2BBU
Chris


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