The 134 GHz band is the highest Primary band in the UK to currently see regular activity. Whilst powers and noise figures are challenging, experimentation is rising, helped by progress in frequency sources. Like 75GHz, the high gains available from small dish sizes facilitate portable operation, provided they are accurately aligned to accomodate the small beam angles.
G8CUB Transceiver - click for higher-res
134GHz Band Plan: The current band plan was updated at the IARU Region-1 Conference in August 2011. Narrowband activity is now centred at 134.928GHz.
Jan-2016: A new UK DX Record was set by Ian Lamb G8KQW and John Hazell G8ACE who further extended the 134GHz record to 35.6km on Saturday 16-Jan-2016, over a LOS path between Cheesefoot Head and Chute Causeway.
Signals were 10dB above noise at best, Temperature was 2.5 degrees C, Dewpoint - 1 degree C.
Atmospheric Losses due to Oxygen and Water Vapour increase at mmWave frequencies. The key enabler for success on this extended distance record contact was lower path loss due to less water vapour attenuation courtesy of the low temperature and dew point was sufficient to overcome the ~9db increase in free space path loss attenuation over the 35.6km path.
134 GHz Equipment at Chute Causeway and Cheesefoot Head
Transmitters: ~100 microwatts output
Receivers: Sub-harmonic diode mixers with no RF amplification
Antennas: 0.3m dishes ~47dBi gain
All transmitters and receivers fitted with rifle sights for visual alignment
G8KQW and G8ACE are very pleased to report two 134GHz qsos on Sunday 20 September 2015. The first from Butser Triangle near the summit of Butser Hill above Portsmouth to Lane End to the SE of Winchester. A distance close to the old UK distance record of 17.2Km.
G8ACE then moved to a site near Cheesefoot Head increasing the distance to 19.2Km, this slightly exceeds the current UK distance record for the band. Antennas at both ends were aligned using optical telescope and solar reflection from mirrors to pinpoint the exact far ends of the link, as soon as the FT817 IF Rx was turned on by G8ACE a signal from G8KQW/P was heard. However propagation had become somewhat unstable during the course of the site move and the signals were exchanged both ways but only in shorter bursts not as continuous reception. Other difficulties such as high level traffic noise from the nearby A272 made copying more difficult than for the earlier contact. Headphones to be taken next time!
The two 134 GHz contacts were made between 15.00 and 18.00 with Temperature 21C, Humidity 67% with a Dew Point of 14.3C
Both sets of equipment built by G8ACE:-
Transmitters using DBES diodes multiplying a 33.6 GHz signal x4 from a Broadern amplifier module available on Ebay. One transmitter using a crystal OCXO signal source x1440 disciplined by RDDS and the other a synthesiser running at 2.8 GHz with a smaller x48 multiplication to 134 GHz. FSK modulation employed.
Receivers using diode mixers driven at 23 GHz with synth LO sources at 2.8GHz again multiplied x48 with a 2m IF frequency. 73 .. Ian & John
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