Monitoring a 1296 MHz Beacon with a Funcube Dongle by W6SZ

      After some testing and monitoring VHF stations, I decided to try the Funcube Dongle on 1296 MHz. I had some doubts
      about its performance on 23 cm.

      The situation here is that the activity level on 1296 MHz is low and whatever activity occurs is hard to use for testing.
      However I am blessed to be within marginal reach of a San Diego Micro Wave Group beacon by K6QPV.

      This afternoon I was able to calibrate my Funcube with the help of another beacon on 144 MHz, 144.294 MHz to be exact.
      It was the first time I had a calibration signal with in kHz accuracy.
      Resulting offset in calibration - 22 ppm.

      Although I had done earlier some monitoring of the beacon I had not been able to be absolute sure about the identity
      of a particular very weak signal.
      This time with my Funcube calibrated on 2 meter, I found the K6QPV beacon within 2 KHz and this time there was no doubt
      about the identity of the signal and as the signal was somewhat stronger this time I could also identify the beacon's call.
      The signal needs to be about 15 dB out of the noise in order to copy the CW.

      Any inaccuracy in frequency at 2 meter gets amplified by a factor of 9 at 23 cm.

      For monitoring the K6Q(V beacon a 20 element Yagi is used inside the house. The situation is
      that the yagi needs careful pointing to get sufficiently enough signal.
      The beacons output is 15 W and the distance is approx. 100 Miles, The path is over the mountains, The frequency is 1296.300 MHz.

      Here are some pictures taken during the run.

        - 1 Beacon located!
        - 2 A little stronger, red colored segments > 15 db above noise
        - 3 Some drift.
        - 4 25 Hz upwards drift
        - 5 returning
        - 6 more QSB
        - 7 Unknown effects ( computer load? )
        - 8 More of the same
        - 9 Frequency lower now -- 1150 Hz
        -10 Strong QSB and more drift
        -11 Environmental temperature beacon? -- 980 Hz
        -12 Weak but little drift
        -13 2 Hour later back in frequency again

        There is some drifting up and down over the couple of hours run. The beacon will drift some, probably due to temperature changes at the beacon. No quantitative data available at this point.
        It also has been noticed that the software shows some changes in frequency readout due to CPU load.
        There might be other small effects.
        The total drift observed is about 7 ppm!

        I am very pleased with these results and believe that the Funcube Dongle can be used for digital modes on 1296 MHz.
        The sensitivity even on 23 cm is adequate as well.
        I like to express my thanks to N6NB and K6QPV for their beacons. Both radio amateurs are SBMS members

        rein0zn at ix dot netcom dot com