40m 4-SQ finished

This weekend SM2LIY came to SJ2W to help out with getting the 40m 4-SQ antenna done. Pelle is our radial expert and the one who has put out pretty much all radials at SJ2W plus also the guy managing the beverage antennas. I would guess that SJ2W currently has got 13km of radials put down on the 2 4-SQ antennas and 160m vertical combined.

Anyhow SM2XJP picked me up in SkellefteĆ„ on Thursday since it was an holiday and the buses didn’t match. When we arrived at SJ2W, SM2LIY had already been there for a while and had continued his previously started work on the radials. We are starting to run short of DL-1000 cable at SJ2W so he untwisted each pair, which means a total of 100 10m lengths of cable was untwisted and then soldered ten by ten to a 6mm2 piece of cable which was later attached to the vertical base.

SM2XLL helped us to get the logs from the 4-SQ area which kept us busy for a while. Some of the logs were too big so we had to cut them in 2-3 pieces.

The FT1000MP MKV gave up, stopped giving out any power just like if the inhibit was activated, so it has been brought up to LuleĆ„ now with help of SM2XJP who drove me up here, and I’ll give it a try to repair it myself. We also went to visit SM2EKM since XJP had never been there, plus checking out a potential tower project for next year.

The 40m 4-SQ got finished today and was briefly tested during daytime propagations. As I expected the antenna was extremely noise free, no noise at all from the town so I believe it will fill its purpose as a complement antenna, mainly for RX to the bigger yagis. We saw something around 25-30dB of F/B which is what we expect and at the center frequency 2.5% of power is dumped in the dummy load and up at the band edges we have 3-4%. When changing direction of the array we see no change at all in dumped power, which means it probably has got quite good symmetry.

We measured about 2.1dB of total loss from the shack down to the 4-SQ. I calculated that we should have about 1.7dB with all the cables, about 200m of RG-17 and about 30m of RG-213. Plus add some connectors, homemade cable joints, switches etc and we end up at 2.1dB. I find that fully acceptable with an antenna located about 170m from the shack.

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