Idea Box: 10GHz Experiment.

Since I am building equipment for the OSCAR 100 satellite with receive capability for 10GHz and transmit capability for 2.4GHz, it got me thinking. Why not make some transmit/receive experiments on both bands ?

The 10GHz receiver part is easy, of course, just use a PLL LNB and a scanner receiver or SDR. I already have a few of those to play with.
Now how to get a signal transmitted ?
For that I could make a wideband FM signal by multiplying a 430-440MHz signal by 24. 432.000MHz will end up on 10368, i.e. in the narrow band segment. Not ideal. Second point is that the sensitivity/gain of the LNB decreases below 10.7GHz.
The LNB appears to have sufficient gain and sensitivity on the OSCAR 100 downlink frequency of about 10.489GHz Why not use that, and create a wideband signal on 10.488GHz. It is well outside the transponder bandwidth and should not interfere with reception of the transponder, at least not with my amateur radio "neighbours".
10.488GHz divided by 24 is 437.000MHz. This frequency with the necessary power can easily be generated by a small (hand held) 70cm FM transceiver.
Now, how to multiply this, without destroying the TX ? The intention is attenuating the output, so the TX sees a decent load, and follow this by a pair of anti-parallel diodes. Instant harmonics. A filter extracting the 6th harmonic just over 2.6GHz could be made with the input circuit of one of the MMDS converters I already have. This will probably have an output of 10 - 30mW, sufficient to drive a quadrupler.
How to make the quadrupler ? I was thinking of using an old LNB (the preamplifier and band pass filter circuit). This is likely to produce 10 - 30mW on 10GHz. Some work with (SMA) connectors for the input/output is necessary.
Finally, the signal need to be radiated. A small horn antenna is intended for the initial experiments.

Now, where should this be tested ?
I have a local radio amateur at a distance of 2km. With the antennas just above the tree top of my garden, and at rooftop at his place I estimate that we have a direct optical path.

Now, the TX equipment for this test will have to be made after I get operational on OSCAR 100, so it will have to wait a bit, but I think it will be an interesting local experiment. It might even be possible to do the experiment this year, but in the spring and summer there is quite a bit of antenna construction and maintenance, so they do not fall down in the next hurricane.

Narrow band experiments will be quite a bit later, though the PLL LNB makes for some interesting receive experiments, and this can be done quite soon, while the antenna construction/maintenance goes on.

If we succeed in making a QSO I can, at least, claim to be QRV on 10GHz ;)