I notice that the frequency calculated by MacDoppler is slightly off from the frequency that I hear the telemetry at. It's off by up to half a kHz. It's not a fixed offset (as I would expect if my Radio was not calibrated on the right frequency), so I can't just offset the frequency slightly in the software.
Is this expected (within experimental error), or is likely that I have something wrong with my setup?
It's hard to tell if I have the same offset for other satellites, because a CW beacon is present even if the tuning is off just slightly. When using a radio to receive AO-73 (vs the dongle) the tuning needs to be quite accurate.
73 Chris ac2cz
I notice that the frequency calculated by MacDoppler is slightly off from the frequency that I hear the telemetry at.
AO-73's transmit frequency drifts around as the spacecraft warms and cools. I remember being surprised to see the telemetry trace increase in frequency on my waterfall display when my receiver was at a fixed frequency. I initially thought something was wrong with the local oscillator in the radio, but my signal generator showed a nice straight vertical line.
There is likely nothing wrong with your setup.
-Joe KM1P
thanks Joe,
Someone else sent me a note off list to the same effect. It makes it hard to track when using a narrow band receiver, such as a normal radio. I've got the hang of it now, once I realized that the frequency would vary depending on the temperature.
thanks
Chris
On Wed, Apr 2, 2014 at 5:12 PM, Joe Fitzgerald jfitzgerald@alum.wpi.eduwrote:
I notice that the frequency calculated by MacDoppler is slightly off from the frequency that I hear the telemetry at.
AO-73's transmit frequency drifts around as the spacecraft warms and cools. I remember being surprised to see the telemetry trace increase in frequency on my waterfall display when my receiver was at a fixed frequency. I initially thought something was wrong with the local oscillator in the radio, but my signal generator showed a nice straight vertical line.
There is likely nothing wrong with your setup.
-Joe KM1P
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Hi Folks,
FUNcube/AO-73 was commanded to Auto Eclipse Mode (ie high power beacon when in sunlight, low power beacon + transponder when in eclipse) at approx 19:45 today.
73s Jim G3WGM
participants (3)
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Chris Thompson -
Jim Heck -
Joe Fitzgerald