Monthly Archives: August 2016

Another adventure to SM2OAN

A couple of weekends ago I went to SM2OAN so we could do some tower work in his 36m tower. His 40m 40-2CD broke this winter so he has built a fullsize 2el yagi that would replace the 40-2CD. I went there on Friday and we managed to rig the tram line and also changed the 5 GHz internet link that was damaged in a lightning strike this summer. I also tilted the 30m yagi so we could get by it without needing to lower that one to the ground as well. This QTH is amazing and with good weather an awesome place to be at.

After a night of rest and a great breakfast SM2GCQ had showed up to help us out. We took the 5el for 20m down and then continued by moving the 6el for 6m down to a lower position to make room for another 5el for 15m to get a 5/5el stack also on that band. After lunch I went up again and we took down the 40-2CD which went fairly well even though things take so much time when doing them in a tower, and I had a few issues but it eventually came down.

After dinner we tried to lift the 2el 40m and it is the same type of design as my inband 2el except different tapering (used yagi) and luckily it was tuned pretty much perfect. He wanted a bit lower than my yagi so it was resonating at 7.08 or so and 1.5:1 on the low side of the band and 1.9:1 at 7.2 MHz which was about what we aimed for.

After I came down from attaching the top 2el for 40m I was quite tired and got a nice cold beer when touching the ground. On Sunday the weather was way too windy to do any more work so we still have the job of lifting the 5el 20m and 5el 15m before we can call the work done. We also will lift the top 40m yagi about 1 meter higher after the tram wire has been removed.

Inband electronics, tower climbing and Hi-Z array work

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 ūüôā

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…

APRS, 868 MHz, inband, SK3W and more

Sorry for the poor update rate, It’s been a lot of people around a lot this summer and I don’t really get the time to sit down and do these things. I spent a few days to build a wooden deck which we also bought new furniture for, it turned out really great!

After I had been down to SK3W a couple of guys from SK3W (SM3XIK & SM3SGP) came up to help me out a bit. We had plans to put an APRS I-gate up in the 60m tower and also the 868 MHz repater (XBEE) that will be used to control the inband tower site and also such things as RX 4-SQ etc that is located far away. It went well and one funny thing was that we lost power from a lightning storm and was just about to put a raspberry pie in the oven. After a while when the power hadn’t come back SM3SGP reminded me that I have an single phase oven in the barn that had never been used and was donated by SM3WMU a few years ago, when I had plans to rebuild the kitchen. So we went out and cut an extension cord which we hooked up to the oven and voila a while after we had our pie ūüôā The power came back again after a few hours.

The project went well but I do suspect that the 5 GHz Ubiquiti links causes some QRM on the APRS frequency because it feels like the I-gate does not hear as well as it should. The 868 MHz repeater works great with really good coverage several km away.

SM3SGP took down the small WARC beam which I lated put in vertical position and improved the tuning a bit so that SM2OKD who will use the beam in the future does not need to do that. I also had some resonance at some winds in the reflector that I hopefully fixed. I think SM3SGP thought it was very nice not needing to do any more climbing, getting to be the ground crew for once.

I also attached a modified 3×1 switch to the 15m tower to switch between the big 15m stack and the new WARC duoband yagi. Some work was also done on the cabinet which will be placed at the inband tower site.

SK3W trip

This year the planned SK3W trip involved trying to remove the top two yagis at SK3W in their 60m tower. These are the two yagis that are hardest to work on since the room to lower them is limited. What we ended up doing was to attach the tram wire from the top of the 60m tower onto the Ericsson tower at 16m height. With a winch on the tram wire we could easily tighten it and with the capstan as lifting power this worked great. SM3SGP did all the climbing and I ended up being ground crew giving orders which was also nice ūüôā

We simulated the 40m stack while being there and ended up with a design that had 28 ohm feed impedance. The 20m antenna design had already been simulated earlier with a close to 16m long boom. When Gunnar and crew earlier had lowered the lowest 20m yagi they found some cracks in the boom which showed it was time to do a renovation of these antennas for sure.

I also met a bunch of nice hams, SM5EPO, SM3SGP, SM3XIK, SM5IMO, SM6MCW, SM5AJV, SM5OXV, SM0W, SM6U and SM0UKE.