[amsat-bb] Re: FM on VO-52 or others

Anthony Monteiro aa2tx at comcast.net
Mon Apr 23 17:48:21 PDT 2007

At 05:16 PM 4/23/2007, Thomas McGrane wrote:
>Using FM on VO-52 is not ignorant. We assume the world is as affluent as us
>but even here in north america, there are many who do not have SSB equipment
>as evidenced by the popularity of ao-51 and the lack of operators on VO-52

Hi Pat,

The issue with FM on a linear transponder is that to peacefully coexist
with SSB you would need to transmit around 10 dB lower EIRP in order to
have about the same load on the satellite transmitter. And since it takes
a few extra dB to decode FM, you would need to use a much bigger receive
antenna to make up for the much lower signal levels.

If you don't TX with the lower power, you basically turn the linear transponder
into a single channel FM satellite and no one else can use it.

However, your point about the lack of activity on VO-52 is well taken. Other
than on field day, I hardly ever hear anyone using it so it might as well
be a single channel FM bird.

Tony AA2TX

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