Because a sun drift scan is no problem with the 1.5 dish, but a moon drift scan did not work, stimulated by Eduard Mol, I started working with a dish that is suitable for 12 GHz.
I opted for a 1.25 meter satellite dish (beam size 1.2 degrees @ 12 GHz) with a normal KU Band LNB ($14)
This LNB has a two-band conversion of 12 GHz to a workable frequency for the rtlsdr or airspy mini.
For the LNB to work at 12178 MHz (W3(OH) it must be powered with 13 volts and it must have a control signal sine wave of 22 Khz, 0.6 volts. I already had a simple sine wave generator and with the help of Michiel Klaassen, I was able to make a simple filter to activate the LNB.
In this area there is not much to receive with a 1.25 meter dish, but the following 3 objects were on my list. Sun, Moon and W3 (OH) maser.
W3 (OH) is a maser at 12178 MHz. Subtract 10,600 GHz from the LNB converter and you can measure at 1578.5 MHz.
The main problem is the relatively narrow beam of 1.2 degrees with a rotator accurate to 0.5 degrees.
This is no problem for a sun drift scan:
A moon drift scan is also doable at 12 GHz and it was good to see that the moon can be detected very well with this dish.
Because after many tries, W3 (OH) failed (after all, it is an extremely weak signal).
I recorded a drift-track-drift scan of the sun. This soon showed that with this rotator the chance is almost nil that W3 (OH) can succeed. There are too many fluctuations in the signal strength.
At the time of writing I am making a few more attempts. Then the dish will be exchanged for the 1420 MHz dish again because on June 10th there is a partial solar eclipse that I want to capture with a drift-track-drift scan. That was a nice experiment but a bit too high an investment to capture thermal radiation only for the moon…. :-(