Yesterday I participated in what has become an annual event, a mobile field-day where radio amateurs in the district drive around in the countryside and make radio contacts on HF, mainly 80m (3.5MHz), as well as on the higher bands. Some of the participants stop on the side of the road and put up temporary antennas, usually low-hanging dipoles for NVIS, others have antennas mounted on the car. This was the third time I participated, and the first time I had an HF-antenna mounted to my car. The organizing team put up a reference station, with the call sign LA1G/P, for comparing antenna systems and radio coverage, as well as serving as a final destination for the trip to meet up and have a chat with other people. This year, like previously, the reference station was set up in the parking lot at Vindfjelltunet.

My car, a ’98 VW Golf Mk4, did not have any trouble with a 100W strong RF field emitted from a “magmounted” antenna on top of the roof. However, there were some quite strong RF noise coming from the car electronics. I did not have time to investigate, it could possibly be solved with the usual EMC tactics of ferrite cores on cables and so on, so for working the weaker contacts I simply turned off the ignition.

During the 180km trip, I made 4 check-ins with the reference station, as well as some contacts with other participating mobile stations. The map shows received (R) and sent (S) signal reports and the distance to the reference station for each check-in.