2020-09-03

A Failed 10GHz Experiment, Murphy's Law. Then Some Success.

 Todays experiment was setting  a LNB up, taped to the 12.5m fibreglass telescopic mast. Tried to listen for the OZ7IGY beacon on 10GHz. Still not audible, landscape, or maybe its radiation pattern, combined with the low gain of the raw LNB is the most probable reason. OZ9GHZ, as expected, is still quite strong - no surprise because there is an even better path to it with this set-up. (See below for the real explanation)

The mast is leaning on the old (no longer) rotating antenna, and initially toppled. Now a bit better "trapped" between the old 6m antenna and the 2m antenna radials, so it should stay up for the day.

It turns out that the OZ9GHZ beacon is audible, even when the signal has to go through the neighbour's roof (thatched), so it is likely a bit of a scatter signal. The signal was quite good, readable all the time.

It turns out the OZ7IGY test was in vain, because later I noticed that all the OZ7IGY beacons I have disappeared. A friend reported that the beacon(s) disappeared around noon, and I did the test in the afternoon. So ... I will have to redo the test another day when OZ7IGY is in operation. Let us just say that this was an example of Murphy's Law in action.

The LNB was then brought indoors, placed on the window sill of a window facing the OZ9GHZ beacon. The signal is much weaker, but still audible, and because the LNB is indoors, the drift of the local oscillator is much less. Opening the window increased the signal considerably (10 - 20dB). Double glazing is not good for 10GHz signals.

In conclusion, monitoring the OZ9GHZ beacon is quite easy at my place. I should probably make a permanent setup for this, maybe with a RTL-SDR for decoding and monitoring the 10GHz beacon band in the Southern direction.

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