I have recently also had some interest in 10GHz stuff. My current experiments have mostly been done with surplus TVRO LNB's and cheap eBay DRO motion detectors.
Unfortunately the DRO oscillators in both of them are not suitable for narrowband, even for NBFM work. My current motion detector DRO modulator is also not up to par as it creates rather low levels of modulation. The plan is to build a better modulator where the current fed to the DRO will be modulated. The DRO would also strongly benefit from a buffer amplifier to get more output and to buffer the DRO. Currently waving a hand within 15 cm of the module can pull the output frequency by more than 1 MHz!
Here's a simple experiment I did with a motion detector as a transmitter and a LNB as a downconverter.
Here is a video of the experiment:
Here is a picture of the transmitter used:
I recently bought two Octagon PLL LNB's which should help me with these experiments due to their low drift.
I have also been thinking about attempting to modify a normal dual polarization LNB into a simple 10GHz transverter for FM, or for SSB with an external LO. The part which makes me most interested is the built in switching between the polarizations, if one of the receive preamps is turned around and modified for transmitting like in the famous Bluecap mod.
Using the different polarizations for transmit and receive should also offer some protection to the receive side as a rudimentary polaplexer. So far all this is just talk with no work done.
After I do some experiments with a few junk LNB's I'll add more stuff here.
New super cheap PLL-LNB has also been found on pollin.de! 2eur for a unit with NXP PLL+VCO+MIXER+IF AMP combo chip.
Shop link: http://www.pollin.de/shop/dt/ODQyODI0OTk-/SAT_Antennentechnik/Satelliten_Technik/Digital_LNB/Universal_Single_LNB_GOLDEN_MEDIA_GM_201_0_1_dB.html
Datasheet for the TFF1017 chip: http://www.nxp.com/documents/data_sheet/TFF1017HN_N1.pdf
While the RDA based octagon/avanger LNB's use a 27MHz reference, this one uses a 25MHz reference crystal.
It also seems to lack any kind of frontend filtering. So either the mixer is also an imagereject one like on the RDA, or the LNB designers decided that images are not a problem.
NXP does not say that the mixer is an imagereject type and their application note for the chipset uses a microstrip image filter.
So this LNB might also be a valid starting point for a 8.4GHz DSN downconverter (high side injection with 9.75GHz LO), but this requires some testing to verify.
OH2FTG Labs >