Microwave Pages
10 GHZ Gunn
"Fun"
John Hamilton, KD5INM
EM04na
Electra, Texas
Below you will see the motion detector with front
cover removed, showing IR unit and waveguide along with
short horn.
Below you see a C&K Systems Motion
detector with both IR and 10Ghz waveguide.
Here you can see the Gunn Diode in the center of the waveguide, the object off to the right of the Gunn diode is the pickup of the waveguide, it picks off the signal from the Gunn diode and the signal entering the waveguide, and mixes them to make the IF for receive.
To the right you see the waveguide removed from the PC board. This part contains the Gunn Diode. The Gunn diode with voltage applied oscillates at Microwave frequencies.
Two signals are used to get RX, an example is, if
your gunnplexer TX's at 10.250 Ghz and the person you are in QSO with is TXing at 10.280
Ghz, then 10.280-10.250=30mhz which is the IF, if you take the 10.250 ghz
your Gunn generates, and the 10.280 ghz signal from your buddy, mix them,
and come out with 30mhz IF. It's all done inside the
waveguide.
Above you will see a HP X532B Wave Meter. This
item in conjunction with the detector below allow someone to set
the frequency on the Waveguide/Gunnplexer
described above. The wavemeter works this way, it acts like a vacumm
at whatever frequency it is set at according to
the drum/dial you see on it. It absorbs/or "sucks out" any RF inside it's
waveguide (Picture to the right). Thus you see a
signal drop at the detector diode (1N23C), you will see a "dip" in your
meter reading when your gunnplexer is tuned to the
frequency dialed in on the wavemeter.
Above you see the detector diode (1N23C)
which is a microwave diode. It is broadbanded detector capable of
detecting 10ghz signals. it is is used in
conjunction with wavemeter to set the frequency of a 10 ghz
transceiver.
These pages would'nt be here without the
kindness and understanding and great help from many Amateurs, I would
like to thank the folks at San Diego Microwave
Group and the folks at North Texas Microwave Society
