The first experiment with very simple equipment, using the low cost HB100 Doppler radar module has been completed: A simple field strength meter (FSM). The idea comes from F6HCC's website http://f6hcc.free.fr/10ghz.htm .
A non-functioning HB100 (with no output when supplied with 5V supplied) was modified according to F6HCC. Another as yet untested HB100 module was used as a source.
But the initial test was done by using a 2m/70cm hand held radio near the module's receive antenna. The "IF" output of the module uses a 10nF capacitor (non-critical, F6HCC uses 22nF) as decoupling for the RF to the meter. The meter used is a low cost digital multimeter (DMM) from the local DIY (home improvement) store.
The reading with 10cm distance from the source (TX antenna) to the sensor (FSM RX antenna), and the reading is a modest 5mV, clearly seen when changing the distance.
Because most hams do have a DMM this provides for a low cost method of testing the functioning of a 10GHz transmitter and/or antenna. The HB100 module can still be had for less than $5, and the modification is simple and well described (with images) by F6HCC. Admittedly, the sensitivity of this meter is low, but it does work.
On the same page F6HCC also describes a more elaborate FSM for 10GHz, involving a diode inside a wave guide, and an amplifier for an analog meter.
However, for a much more sensitive FSM I would likely use a low cost (surplus) low noise block converter LNB, usually used with a satellite TV receiver dish. This has lots of gain, and you can probably salvage one from a discarded satellite dish. The signal on 10GHz is amplified and converted to a much lower frequency, usually around 250 - 750MHz, where a diode detector is much easier to make. Also a simple multimeter (analog or digital) can easily be used in this application.
For measuring close to the lower band edge (about 10.0GHz) it may be a good idea to modify the LNB with an external DC supplied, not via the IF cable, but directly through a hole in the casing, and disconnect the DC "RF-choke" on the PCB from the IF connector.
Further, if there is a filter on the 11-12GHz side, it may be an advantage to by-pass this for greater bandwidth.
The gain in such an arrangement may be rather high - too high - but reducing gain in a system like this is easy. Just put some RF (microwave) lossy material between the LNB and the signal source...
There is, of course, the possibility of bypassing the RF (10GHZ) amplifier and the RF filter in the LNB, and connect the sensor antenna directly to the mixer via a piece of coax (semi-rigid coax will be the best choice), thereby reducing the gain.
If you do this, you might salvage some useful GaAsFETs, if you can avoid destroying them with static electricity.
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