When purchased the Solfan Gunn modules are usually set to 10.685ghz and have some components across the terminals these have to be removed. The three terminals are ground, 7v to Gunn diode and receive diode. The modules can easily be tested as shown below.

A field strength meter for testing Gunn modules and antenna gain can be made by connecting a 50uA meter across ground and the RX diode terminals. 7v dc can be applied to the Gunn diode terminal on the TX module on test. Do not let the Gunn supply fall to 5v or less or else the diode will be destroyed. The meter will read approx. full scale with about 6" separation. This gives a quick indication of the output and can be used to compare the gain of different horn antennas.

Getting the TX onto the right frequency is best done by applying a modulated 7v to the Gunn diode from a modulator such as the Bob Platts Gunnmod2 kit and locating the signal on a receiver. The tuning screw can then be slackened off and carefully screwed in reducing the frequency, at the same time tracking the signal on the receiver until it arrives at the desired freq. The lock nut can be tightened and sealed with nail varnish.

Do not look into the wave guide when the  
       Gunn module is transmitting

When first establishing a link don't be too ambitious. Test the equipment locally about the garden. Then take it out in the field and try a mile or so to get the feel of things. This should produce good results with a standard horn and LNB. Greater distances can be covered by the use of higher gain horns (20db) or dishes, small 35cm ex-bsb dishes or 60cm Astra dishes are OK but are very sharp to adjust.

Setting Up Gunn TX Modules