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# <a name="Communication Team Workshop Tues"></a> Communication Team Workshop Tuesday June 21, 2005

Who: Tim, Glenn and Andrew

Where: Andrew's workshop

## <a name="Prelab"></a> Prelab

From Tim:

    1) We seek to avoid 1575.42 MHz. For convenience, it is nice if (d)
       remains 14.

      f_receive = 10.2451MHz * 187/14 + 10.7MHz = 147.545MHz

    The 11 the harmonic of the 1st LO is 1505.3MHz, the 12th is 1642.14MHz.

    The distance from the GPS carrier is therefore

      [-70.1221, 66.7232]MHz

    I don't expect to do any better than this since my eye tells me the
    SAW filter notch is a bit closer on the high end and the
    notch-to-notch distance is about 112MHz.

    Is this receive frequency (147.545MHz) ok for us?

According to Glenn, 147.545 MHz is fine.

## <a name="2m Receiver reflash and SINAD me"></a> 2m Receiver reflash and SINAD measurement

So we reflashed the recovery node to set the 2m receiver's DPLL divisor to 187/14 (control word 0x40) and took a look at the where the LO's harmonic spikes were. They fell close to where we predicted (Tim: measurements?) and we called it good.

We then tried to get the 2m's SINAD back to the -100 dB that we originally had, and we just couldn't do it. About -88 dB was the best we could do, which was disappointing. Something happened to the 2m receiver... we wonder what.

## <a name="2m/GPS/ATV test"></a> 2m/GPS/ATV test

Once again, we put the avionics module + payload module with the 2m receiver on top of a ladder in front of Andrew's house and put various laptops -- and lights, since it was of course dark by now -- on a table. We got to use Bruce's flashing red lights since the ladder was in the street - fun! We used Cantalope to turn on and off parts of the rocket, and used the Jupiter's DOS-based `labmon` software to monitor how the GPS satellite lock was. We turned on everything - ATV, wifi, 2m, you name it - and the GPS didn't care one bit.

So hooray, the ATV/2m/GPS interference problem has been solved.

Now we just need to figure out what happened to the 2m receiver, or replace it with the old LV1b receiver.