03 Mar 10 GHz over 77km
Last Updated on July 22, 2023
On February 24, 2021, Robert VK3KRD, Neil VK3BCU, and I (VK3FS) headed out portable to try and work 10 GHz between Mt Kororoit and Mt Martha – a path of 77km.
Having had much success with the lower microwave frequencies over the past year, we finally managed the first successful 10 GHz contact between us. The path distance is 77km which is pretty much clear line of sight, of which 2/3rds is over Port Philip Bay.
Robert VK3KRD and Neil VK3BCU went potable to a dirt road adjacent to Mt Koroit which is north-west of Melbourne at an elevation of 200 metres. I was on Mount Martha in a new estate that is 126m above sea level with clear unobstructed views south from the heads of Port Philip Bay to Melbourne’s easter suburbs to the north.
In microwave, like in all things amateur radio, things don’t always go to plan the first time, and this was no exception. There had been a few failed attempts previously where dodgy coax relays and path issues dogged us. Fortunately, all that was about to change on this, our third outing.
For those unfamiliar with our hobby, The 3-centimetre or 10 GHz band is a portion of the SHF (microwave) radio spectrum internationally allocated to amateur radio use on a secondary basis. The amateur radio band is between 10.00 GHz and 10.50 GHz.
Rob VK3KRD’s setup at Mt Kororoit
Rob’s IF radio was a Yaesu FT-780R with a 15dB pad between the radio and the transverter.
Rob’s antenna was a 600mm prime focus dish fed with a home brew waveguide and flange.
Rob’s takeoff to the south, despite being rather high, was not totally unencumbered.
Andrew VK3FS’s setup at Mt Martha
At Mount Martha, my station’s IF radio was an IC-705 and I was using a 750mm offset dish. At the focal point was one of Paul W1GHz’s dual-band 10 and 24 GHz feed horns. It’s a one-piece machined horn designed for common offset dishes that works exceptionally well on both bands.
At Mount Martha, my station’s IF radio was an IC-705 and I was using a 750mm offset dish. At the focal point was one of Paul W1GHz’s dual-band 10 and 24 GHz feed horns. It’s a one-piece machined horn designed for common offset dishes that works exceptionally well on both bands.
My path north was clear across the bay to the city. The perfect location for 10 GHz over 77km. Both stations were using Kuhne 10 GHz transverters with an output power of 250mW.
