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Microwave technology for the new band of 122 GHz

There is a discussion about a band where the wavelength is only 2.45 mm long. Some of the microwave bands were reorganized at the IARU conference in Vienna on 28th – 29th February 2004. The 145 GHz band was canceled and two new segments at 122.250 – 123 GHz and 134 – 141 GHz were opened instead. This can be seen in the table published by the Czech Telecommunication Bureau (CTU) as an attachment to an ordinance issued on 19th April 2005.

The 122 GHz band is a new one. The equipment for this band has been obtained simply by retuning the idle transvertor originally made for 145 GHz. The frequency of the base oscillator has changed and the same is true for the multiplier. This can be seen in the following schematic diagram:

The first contact took place on 15th June 2006 and was made from one table to another overcoming a distance of a few meters whilst still in the workshop. Further testing was done on 2nd August 2006. This time it was carried out outdoors using reliable routes in the town of Horni Stepanice. The distance between the stations was several hundreds of meters and the transmit/receive mode was SSB. Another test was made across the Benecko Valley over a distance of 1.2 km, this time using only CW. This is the maximum that can be achieved with an amount of power output that is hardly measurable (probably not even microwatts) and Procom antennas with a diameter of 25 cm.

The photographs below reveal what went on during the first contact between OK and SP on 76 GHz and 122 GHz, which was made on 20th August 2006 during the gathering at the 8th Technical UKF Convention in Zielenec (JO80EJ).

Photos from tests in Bavarian :

Source of information: OK1UFL, OK1AIY
Translation: OK1HWU