16 June 2021

10 GHz WBFM activity 2021

The yearly 10 GHz "old mode" FM Contest was last Saturday. That is the only chance to play with WBFM, Gunnplexer, HB100 and show your presence in some official documents.

LNB over a tree.
Three operators managed to arrange three points with mutual visibility in NW Italy, max distance above 100 km. My setup was HB100 on the TX side and LNB+RTLSDR+laptop on RX side.

Since my spot was 15 minutes hike from the car I had to minimize the weight: everything you see in the pictures was carried on my shoulders (except for the tree).

Having skipped the year 2020 contest because of the pandemic, we operators have forgotten some details of our setup, like the correct orientation to match TX and RX polarisation which caused some confusion when looking for each other when we knew we had to be heard.

In the end we all managed to work each other without using the parabolic dish boost, which is a good achievement thanks to modern sensitive LNB. The 2 MHz waterfall view does help to locate unstable transmitters, even if my HB100 constantly under the Sun moved just some 200 kHz on 2 hours.

As planned I worked the two operators at 35 km and 99 km. Once you sort out the correct polarisation, HB100, Gunn and LNB antenna patterns are wide enough to allow very comfortable beaming, to the point that my LNB was waving at the wind on the branch and there was no QSB at all.

TX head on a lightweight tripod.

It was a pleasant afternoon on the field. Too bad the season already calls for family/vacation trips and it is hard to involve more operators.

PS: my distance record on the same setup is 144 km from the same contest in 2019.