Tag Archives: AFS

SSB AFS Contest

With snow on the ground and the sun in the sky it must be time to do some winter contesting. This weekend members took part in the RSGB affiliated society SSB contest, this takes part on 7 and 3.5 MHz from 2 till 6 PM.


With a small amount of snow on the ground, and ambient temperatures around +1C we opted for the inside operating position. The station comprised of an Icom 7600, Expert 1.3KFA solid state linear and a doublet antenna at 30m on the bunker tower.

Band conditions on 7 MHz only supported “long skip” with some good signals from Scotland and Ireland, although after a short while even these distances proved difficult. The maximum usable frequency had moved down to 4 MHz, and so a switch to 3.5 MHz was required.


A look on the Hack Green SDR confirmed 3.5 MHz was very busy, and we soon realised it was hard to find a run frequency. We also noticed a large amount of rasping electrical noise on 3.5 MHz, and so decided to investigate further. At times the signal meter was reading S9 or s9+10dB and so hearing weaker signals was proving impossible.

We changed the mains supply over from fixed to generator, and the noise floor dropped by 3 to 5 S points, interestingly it would seem the noise was coming from the mains, and so this would require some further investigation and most likely a mains filter project for Chris G8OCV.


32160162702_84e7a7833e_kThe generator proved to be a little problematic, for some reason it was running a little lean, and so the engine was sounding rather more stressed than usual. This caused the generator to “brown out” a few times as it coughed, wheezed and spluttered in its attempt to generate circa 2KW at 240v. ¬†As they often say if something could go wrong, then it most probably would while your out in the field.

Hopefully the generator will be a simple fix, probably just needing a clean to the carburetor and no doubt another job to be added to the “to do list” before our next event.


While we had some fun, drank some tea and generally worked a few people I think its safe to say our score wont be breaking any records. As always we learnt a bit, had fun and generally tried to stay warm.

1.8 MHz CC AFS

Last night saw activation for the 160 metre club calls affiliated societies contest. This is a slow and relaxed contest, with an emphasis on beginners (full rules here).

3 members of the group decided to run the contest from the bunker as there is already an antenna suitable for 1.8 MHz on site. We carefully negotiated the car on to the field (in heavy rain), with the wheels slipping everywhere. As some of you may remember, we have had vehicles stuck in the field before, so it was our concern at 8pm at night with the farmer long since resting at home, that we mustn’t become stuck!


The field was boggy, but we managed to get close enough to run a coax to the mast, and set the station up on the car dashboard. Given we didn’t know the state of the antenna, we took a large ATU with enough inductance should it be needed, with the intention of running a long wire if the doublet had failed. The Icom IC7100 was used to provide the maximum 32W for the section of 160m in concern. Power was provided by a Honda EU20i silent generator. We also opted for a small fan-heater to keep the car warm and small table-lamp to provide light.¬†Fortunately the doublet was okay, and we got underway.


Here we see Dave G7UVW operating the IC7100 through a rain-covered window.

Conditions were very down on last year’s event. The band was cursed with environmental noise. It also didn’t help that we had a dodgy piece of feeder coax, which was undiscovered until the last 15 minutes.

Overall, we worked 34 stations, and claimed a score of 564.