Monthly Archives: June 2011

Antenna switch progress

This weekend they promised rain at SJ2W so I decided to stay in LuleƄ instead. Spend some more time with my girlfriend but also get some work done on the electronics. Earlier this week HA1AG guided me a bit through dissembling the FT1000MP MKV which had stopped delivering any output power. After checking the voltages etc to the finals which looked OK I started going backwards to see where the RF signal disappear and it did just before the finals. So I started measuring the bias voltage of the amp stage and it showed that the inductor in series with the bias was burned. So after changing it the radio worked again and HA1AG guided me through some of the tuning process along with the tech reference of the MP. Thanks to Zoli that helped me an convinced me to try to fix it myself before sending it to him. So instead of paying a lot in shipping it ended up costing me about 5 euro including of the inductor shipping.

Today I built another powersplitter, this one is intended to be used on 10m now when we hopefully soon get the 10m yagi up in the 60m tower. This time I put a fan on the device since we noticed that the 20m unit got quite warm in the WPX CW contest. So now when there is no radio activity I will plug the air holes and have the 15w heater inside each box to keep away moisture and during the contests we remove that and start the fans. So I will need to modify all the boxes which are currently at SJ2W as well. I also built a 6×2 switch which will make it possible for us to route four radios to any of the antennas, up to 18 different antenna systems (3 on each band). I have however run out of 7/16″ connectors so until I get hold of some more the switching system can’t be completed. This is because each band need to have a powersplitter even if we just have one antenna on the band. This is because of the A/B output on the splitbox, making it possible to route the powersplitter to either 6×2 #1 or 6×2 #2.

I am not very pleased with how the 6×2 turned out. The mounting plate for the connectors/board is fine but the casing wasn’t very nice. I couldn’t fit it in the milling machine so I had to bend it by hand which is always a mess, at least when not taking it slow and careful. I don’t like to spend too much time on making these things look perfect, I try to make the visible things in the shack look perfect, this kind of things is fine just as long as they work.

A beautiful day

A beautiful day to do work outside. I arrived yesterday (Friday) and SM2XJP picked me up in SkellefteƄ and we headed to Elektroskandia to pick up some material I ordered. Some guy anchor rods for two towers, grounding rods and some 25mm2 copper wire. After that we headed to another shop and bought 60m of 10mm re-bar and some cement so make some concrete anchors for the small tower (plus a lot of extra re-bar). On Friday evening I spent some time welding together a mesh of re-bar for the anchor plates and on Saturday morning I poured the concrete into them and now they are curing.

On mid day SM2XJP came by and washed his car. While he was doing that I went out in the forest to clear more space for where the 40m tower will be placed. The stupid thing with new chainsaws are that they don’t use up a lot of petrol, which means less breaks to rest. After maybe 2 hours of cutting I got tired and spent an hour on the couch. A bit later SM2XJP came by again and we had some BBQ which made my fall a sleep later in the sofa, but in the evening I had gathered enough strength again to do a late shift. So I went out and started to assemble elements for the 12/17m duobander. However the mosquitoes ran me off and I went in to update the blog instead.

I’ll be back later with more pictures.

Hot weekend

Last weekend we had really hot weather, it was awful. Us northern vikings are not used to having over 30C and when there is no wind at all and no water nearby to swim in we aren’t very happy. The vodka me and SM3JLA drank on Friday night was not the best either since it made coping with the heat a lot worse, at least that is my guess.

Anyhow, after we recovered we did fix up the 6el for 10m that we intend to put up at 45m in the 60m tower. This antenna is meant to be an antenna which will be great during the period before the band really opens and closes and with marginal propagations, since it will have very low angle of radiation. However we are missing a feed line for it, so it will need to wait a bit more until it goes up. On Sunday we spent time doing lumber jacking. I did cut down a bunch of trees while SM3JLA was putting them in piles so that its easier for the neighbor to pick it up with his tractor and timber wagon. This is so that the 40m tower fits. A bit more and then we can measure out exactly where we want it and can see if anything more need to be taken down for the guy wires.

A problem we’ve gotten is that our usual aluminum supplier does not want to sell to us anymore. Its been done so far as a favor since they usually don’t sell to people without companies. But now they claim that prices has doubled and we’re trying to find some other place to buy aluminum. So unfortunately all the antennas project this summer are put on hold šŸ™ Its mainly the 3el mono bander for 40m that we feel “pain” in all of this, since the antennas for the 40m tower is not such a rush since the tower is not up yet. If any Swede is reading this and got a tip of where to get hold of decent priced aluminum, please give us information about that.

I gotta tip about a new blog which I read and like a lot. I pretty much read through it in two long sessions, very interesting reading about the adventures of K4ZA who is a famous tower climber in the US, this also made me order his book. Check it out at .

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.