Category Archives: Electronics - Page 6

Trip to SM2EKM and RX-array work

Posted by sm2wmv on September 26, 2016 Comments Off

I spent a couple of evenings at SM2EKM last week helping him with some tower work. It should only have been one trip but since I managed to mess up it needed to be two. I was going to disconnect one of his 5el for 20m since he has got a problem with one of them and extend the cables down to the ground so he could work on them himself. Unfortunately I mixed up the cables and ended up attaching the two antennas together and the coax leading into the shack was left hanging 🙂 So I went back the day after and fixed that. We also concluded that the top 20m yagi has got an issue which needs to be fixed, this will however be done next year and I believe I can do it in the tower by tilting the yagi without needing to take it down to the ground.

I have also spent time working on the RX-array. I got most hardware installed such as preamps, ground rods, coax etc. I also got the RF-link tested and it switches the array properly so now all that is left is to install the cabinet and pull out the 300m of coax needed to reach the array.

It was also very nice to get a visit from SM3JLA and his girlfriend and we concluded that he should start coming up more often again, at least I did 🙂

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SM2OAN, RX-array and carpentry

Posted by sm2wmv on September 26, 2016 Comments Off

Since we hadn’t finished up all work at SM2OAN I ended up going up once more. We first pulled up the 20m yagi (5el) into position and after that the 5el for 15m. When this was done we removed the tram wire and we lifted the 2el 40m a bit higher (as high as we could). The work has gone very well and I believe SM2OAN is now very happy about his setup, especially getting the 2el 40m added plus getting a stack on 15m as well. I also built a stackbox for him so that he can switch it. After we were finsished, we went to SK2HG since they had a meeting and it was very nice to meet some friends.

I have also spent quite a lot of time at SJ2W lately. I am trying to work in hours so that I can go down on Thursdays which gives me a whole day more. Normal weekends are way too short but this gives me another day. I’ve done a lot of work on the Hi-Z RX array building Bias-T to get DC power there, finishing up the RF-link to switch it etc. I used 16mm water tubing to protect the RG-6 coax going from the cabinet in the middle out to the verticals and I will have about 50-70m of it so that I can have the coax on the ground close to the RX antenna. Further away I will put the coax up in the trees as it protects it better.

I have also built some more protection for the rotors of the different towers, the military tower still need some work before its finished but I believe I’ve done pretty good progress on it at least.

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Various work

Posted by sm2wmv on September 26, 2016 Comments Off

I got to borrow and ACOM 2000A from SM2OAN when I was up helping him, so I have built a shelf for it so it doesn’t stand on the floor. I have also painted a few things, such as the rotator cabinet for the moskojärvi tower and also the cabinet I built for the inband tower. Hopefully I will get this cabinet moved to the proper location next weekend and installed partly.

I also changed the power supply to the WIFI-link. I am trying to remove all the switched supplies that are not really needed and can be replaced by linear ones. I bought a few linear ones from SM2RHL during the SKRA flea market which I put to use.

Me and SM2XJP also talked to the power line company about a potential noisy transformer that is currently not in use. So they were kind enough to remove the fuses before the SAC CW contest and man the bands are quiet now. There is still at times some noise from the power line so we will need to try finding that and telling them about it.

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Inband electronics, tower climbing and Hi-Z array work

Posted by sm2wmv on August 29, 2016 Comments Off

My last vacation week I spent time working on the inband electronics, the 868 MHz RF-link that will be used to control remote stuff at the station, such as RX-arrays, 4-SQ at distance and mainly the inband tower site. I have made some 868 MHz modules with BPFs on the input which also acts as surge protectors. I climbed up and exchanged the one we put up in the 60m tower (which was temporary just to try) with the proper one and it seem to work great. I also had the laptop with me and re-configured the APRS I-gate but of course I was missing some DLL-files so I spent probably 15 minutes figuring that out at 52m with the laptop. Luckily I had internet coverage up there 🙂

Some work has also been done getting some boxes around all the rotors for the rotating towers. I plan to make a roof for the military tower also before the snow arrives, since it happens that it freezes up during the winter.

I also started to work on getting the Hi-Z 4-SQ array that SA0AZT donated. He won it when he was in Dayton and didn’t really feel he needed it, so he was very kind and gave it to us instead. I have made some verticals from old CUE DEE 20m yagi elements which I extended a bit. I also made some insulators from some plastic tubes I got from SM3WMU once and managed to attach them.

SM2UVU came for a couple of days and helped me out, we got a lot done so the current state is that the verticals are vertical in their proper position. I have bought some 16x2mm plastic pipe (150m) that I will use to put the cables in between the verticals, to help protect them. I will also put the coax from the array on the ground the last ~50m so that I don’t get any strange effects from having the coax up in the air. So I want to put the cable in the plastic tubes so it might survive the lonely bored critter.

I went to the SK2AU club meeting, which I try to do at least once every summer when I have vacation and it was great. I managed to buy 90m of 1/2″ and 45m of 7/8″ for a decent price. Me and SM2UVU also went to the SK2AU flea market on the Saturday following the club meeting and scored some stuff. I bought a bunch of linear power supplies which will come handy now when I am trying to get rid of the unnecessary switched supplies.

Stay tuned…