10GHz HB 100 Test With Modulation.

 Today was an active day with the soldering iron.

As the very first test I just connected the HB100 modules, preset to 10375MHz and 10450MHz on the desk, just to see if I could hear the carrier with my LNB mounted outside the house, and pointing away from the house. This is the LNB I have used for beacon monitoring, so I know that it works.

A primitive modulator using the LM386 PCB module with gain control (from China) connected to the 5V power supply (yes, 7805) was tested, making sure that the peak voltage would not be too high for the transistor in the HB100 module. This initial test was done with a 150 ohm "DC-dummy-load" in place of the HB100, and the LM386 input was connected to the earphone/headphone connector of a transistor radio. The voltage swing was about 50mVpp, so well within the limit.

Time for an on-air test. I connected my QO-100 base radio for TX, without RF output, and used the CW side tone to modulate the system on 10450MHz. When the HB100 was in an optimal position the wideband FM modulated CW signal was loud and clear in the receiver. Not very strong, but with significant quieting and a clear CW. My callsign has been sent out on 10GHz.

What I need to do now is getting the system into a box with switches, a tone generator the modulator, likely an electret microphone and a bias tee for the LNB, plus connectors for getting signals and DC out to the LNB and HB100, and the IF signal in from the LNB, and I should have a working system.

Right now I do not have any stations to test with, but a local amateur has a HB100 module and LNB somewhere, so he might be available. Otherwise I may have to build another system, so I can get some tests done.

The transmission distance tested right now is about 8m, so there is plenty of room for improvements.