New world record: 139 km on 122 GHz
17 Feb 2020: QSOs between
Mike, K6ML, on Mt Vaca (CM88WJ75ON, 835m ASL) and Oliver, KB6BA, (at 1225) & Jim, N9JIM, (at 1250), both on Mt Umunhum (CM97BD18VJ, 1016m ASL)
WX: Dew Point -11C, Air Temp +15C, path loss ~ 225 dB, atmospheric loss ~0.35 dB/km
CW was used, 122 GHz signals were very weak (7 dB above the noise in 22 Hz; -13 in 2500 Hz equivalent) with QSB down to the noise floor. Dishes were aligned on 24 GHz (71 dB above the noise) prior to QSY to 122 GHz; we heard signals right away on 122 GHz.
We used dual band radios designed by Mike (using 122 and 24 GHz Silicon Radar sensor chips and 60 cm satellite TV dishes) with somewhat less than half a milliwatt of output power on 122 GHz. Mike & Oliver focused and aligned the radios in previous field tests from 15 to 80 km. Jim suggested the 139 km path from Mt Umunhum (“the resting place of the hummingbird” in the Ohlone language) to Mt Vaca (“cow” in Spanish) and also taught us the weak signal EME CW exchange technique.
Some photos and videos will follow.
Photo: screenshot from youtube video K6ML