Category Archives: Tower work - Page 15

40m yagi fixed

Posted by sm2wmv on October 18, 2010 Comments Off

I got a call on Thursday from SM2LIY who was at the QTH and said that the 40m yagi had tilted 90 degrees. This made me very depressed and I called SM2XJP so he could go out there and check if everything seem to be ok and it was just a matter of “twisting” it back and tighten the clamps. He called back a few hours later and confirmed that everything looked OK which made me a bit more calm.

I arrived at the QTH on Friday when it was dark, so I could not see the mess myself and started to do other work instead. I had gone to SM2EKM and picked up the SB220 he borrowed me to use on the 2nd radio during CQWW SSB that I plan to do SOAB HP as SJ2W. When I connected the amp and started it up it did blow the fuse and the anode current meter getting floored. This made me very scared but I was confused since I had handled the amp with care. So I checked to see if the tubes were properly in the sockets since I suspected maybe some glitch making it not “cut off”. I moved the tubes a bit and started it again and the amp was running, so I thought the problem was solved. Until I stepped upp from the chair which apparently made the table move slightly and bang the fuse went again. This made me very confused and I started to look at the tubes and did notice that the anode in the tube was lose and at some angles it did hit the cathode creating a shortcut. This made me very upset thinking I broke the tube so now I was not just nervous to climb the tower on Saturday morning but also the call to SM2EKM to tell him I broke his amp.

On Saturday morning I had a hard time eating anything because I was really nervous for the tower climb, for some strange reason since I’ve done it many times before without problems. I just had one of those days where I didn’t feel like doing it but I did pull myself together and climbed the tower mid day on Saturday. It went pretty easy but I avoided looking up since I could see some ice in the tower at some points, like where antennas were attached to the tower. However nothing fell and after I climbed up I broke the ice loose and threw it down, so that it wouldn’t hit me on my way down. Well in the top of the tower everything went very smoothly. I loosened the clamps more and with help of the boom support I could turn the yagi back. However the elements look worse aligned than compared to when we put the beam up, so I am afraid that it might twist even more this winter but hopefully it will survive as long as possible and we can fix it in the spring/summer.

When this was finished and I had gotten down to the ground again I called SM2EKM and told him what happened and he said “But Mikey, you should know that I have lots of tubes” so he will send two new tubes with me down to replace the ones in the amp now. So I had been nervous over nothing, both when it came to the tower climb as well as the call to SM2EKM 🙂 Thanks Jim!

After this was done SM2XJP and I did some work down at where the 40m 4-SQ will be placed but after a few hours we pretty much gave up. The snow makes it too hard and we don’t really have time to do everything to get the 4-SQ up before the ground will get rock hard and even getting rid of all the trees and branches is a big job. So this will need to wait until the spring/summer to be done. I am considering putting up a loop with apex @18m vertically polarized as EU antenna for 40 to use when beaming some other direction with the beam.

Here are some pictures taken by gf Anna!

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6/6el stack finished for 15m

Posted by sm2wmv on September 29, 2010 Comments Off

Now another antenna system is completed at SJ2W. This weekend with help from SM2XLL, SM2XJP, SM3JLA and myself (SM2WMV) we got the 15m yagi up in the air. Its funny now that a 6el yagi for 15m feels like a tiny antenna, while a few years ago it was a monster.

The upcoming weekend I will climb up with the cable for the stack and also the newly built L-match (further down in the post) so we can test it out.

GF Anna took the pictures (except the halo pictures, taken by SM3JLA).

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I also did some work this week in the lab at the university. I did build a couple of power meters and calibrated them. I also build the L-match for the 15m stack and I managed to get VSWR of 1.006 so I think its close enough to a perfect match 😉

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160m vertical finished

Posted by sm2wmv on August 29, 2010 Comments Off

This weekend we did the job I have been fearing the most of all. I don’t like climbing in the vertical at all, since its guyed with ropes and very high it moves around A LOT. So we guyed it at two levels with wire to make it a bit more steady but my plan of putting up two more tower sections failed since it just didn’t feel good. So instead we put up one more section with a 9m long tube attached to it. Its half of a 40m yagi director which is attached along the tower section. We hoisted the whole thing as it was, to avoid needing to climb up and raise the top tube. It went pretty smoothly even though we had to abort one lift because of some bad planning.

I don’t know at all if the top tube will survive high wind. We saw last year on our tube which was even longer (14m) that it survived the winds pretty well except that the long guy wires were more creating trouble than actually helping the tube. Unfortunately that tube broke because of a bad joint between two 60mm tubes, which was made way too weak. It was taken from some old vertical and I did not check how well that joint was made, apparently a mistake. So I though that if an element survives on a 40m yagi which is higher up and with also horizontal load it should be possible to hold also as a vertical. But I might be thinking all wrong and it might snap.

So SM2LIY came up with the idea of attaching a cable from the top of the top tower section and in case of failure of the top tube we can just pull that line out and attach it in a tree and we have an INV L. This is just done as a backup plan if something happens in the winter.

I hope I never need to climb that tower again, because its very scary when it moves around so much, so lets keep our fingers crossed that our thinking has been correct.

So left to do when it comes to antenna work for the autumn is to put up the low 6el for 15m to make it a 6/6 stack and to put up the 4-SQ for 40m. So the late autumn and beginning of the winter will probably be spent on making room for the 40m rotatable tower, I doubt we will have it up this year but we will try to make as much as possible done so we can put it up early next year.

I also hooked up the control cables for the BPFs to the openASC box so now the station is almost ready for serious contesting! I took some pictures as well of how it looks now, the SO2R position at least.

Tnx to SE2T, SM2LIY and SM2XJP for the help during the weekend!

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Phase box connected

Posted by sm2wmv on August 22, 2010 Comments Off

Yesterday (Saturday) SM2XLL came over to help me out at the station. I never climb the tower when being there alone, the same goes for the chainsaw because it is too dangerous if something happens. So he did watch me while I did first climb up to 55m to add the side support for the top 6el yagi. This had to be done since it was removed when we moved the beam during the 40m lift (thanks again Gunnar, SG3P). When I had started to work on that boom support the rain started and it kept raining like crazy until I had done all work in the tower, approximately 2.5 hours. When I came down there was barely any dry spot at all on me. I got the 180 degree cables connected and the antennas hooked up to the new stackbox, making it possible for us to phase shift the different antennas and steer the vertical lobe into four different angles. These angles are 6,13, 17 and 25 degrees. All three antennas are always in use, just phase shifted.

The first tests of the system shows quite a lot of signal improvement to some stations. Beaming EU for example some guys were 15dB louder on a higher angle compared to all antennas in phase. When we tried some towards US most of the time 6 degrees was the best but when band opened up more 13 degrees sometimes worked better. So I believe that during really good openings the higher angle might be useful while towards west coast I believe that 6 degrees will be better almost all the time.

Here are some pictures and also a video from the tower