In Part 4 I described the assembly of 2.4GHz uplink electronics. I then addressed my attention on improving the uplink antenna.
I recently purchased an 80cm offset dish with the intention of using it for the uplink and, eventually, for the downlink as well. The next decision was how to feed it. The diagram below shows the principle of a parabolic dish.
The dish was mounted in approximately the same position as the long yagi it was replacing (see below).
It took a few attempts to get the dish accurately aligned for maximum signal strength. The performance was a modest improvement over the previous yagi, although not stunning. I put out a CQ call using CW and got a reply. After the subsequent QSO I got called up by another station. So it clearly works, but there is still room for improvement. I suspect the beamwidth of the yagi feed is still too narrow for optimum illumination of the dish. There will also be a loss of 3dB due to using linear polarisation instead of circular. I have ordered a small patch antenna which I am going to try next.
My Adventures in Satellite Communications - Part 6 (patch feed)
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