[amsat-bb] Re: AO-51 on mode V/U BBS

Sun Jan 24 08:54:21 PST 2010

Hi Enzo,

As Mark has pointed out, you need a fair ERP to get in to the mode L
receiver.  I have about 2500 ERP, and can get in fairly reliably with no
trees in the way, but not as well as I did back in the KO-23 days.  Because
of antenna placement (?) it sometimes makes a big difference whether the
satellite is approaching or leaving, both on packet and mode L voice.

Two things to check are your frequency and calibration, and your deviation.
Not all rigs, and especially transverters, are accurately calibrated at that
frequency.  Mine are not, and I used a laboratory grade frequency counter to
get the correct values.  

Also, there is a consensus that the actually uplink frequency is about 3 KHz
higher than published.  I use 1268.703 MHz.  The receiver is fairly wide,
but every bit helps.

Finally, make certain the 9600 baud deviation is good, preferably with a
good deviation meter.  

Good luck,


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