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!
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
This weekend SM2XLL and me spent time working on the 20m yagi getting it put together. On Monday morning SM2XJP arrived and helped me to lift the beam up at 23m. So now we have the 6/6/6el stack for 20m complete. Tomorrow I will do some climbing putting up the side support for the boom and also connect the coaxes to the 3 antenna stackbox. This stackbox is built so that it is possible to take different yagis 180 degrees out of phase, to steer the vertical lobe. This will be very interesting to test and according to simulations from 6.5 degrees (max gain, all in phase) to up to 26 degrees or so, we will not have more than 3dB drop in any angle if we switch the phase box with 4 different combinations.
Yesterday I decided to remove the rotor of the big 60m tower. This is because it is currently not strong enough, it has got some cracked weld and also I found a big crack in the metal when I removed the gearbox. This is however rather easily fixed and I will add some more iron to it so that it gets more stiff and doesn’t flex so much.
When SM2XJP arrived I decided to climb the tower (I don’t climb it when I am here alone) to add the boom side support for the 20m yagi and tighten some stuff up on the 40m yagi. I also needed to attach the cables properly to the tower. I use duct tape every 50-100cm or so on cables running in the tower, to avoid them from bashing against it when its windy. When I arrived up to the top 20m yagi the boom support was missing its clamps, so I could not do that. However I finished up the coaxes and on the way down with help of SM2XJP on the ground we lowered the 20m temporary 3el yagi @20m and also the low 15m yagi which will be moved up to 17m when the top 15m yagi (27m) and low 20m yagi (23m) is in place.
I also have fixed the cables between the 7/8″ in the tower and the 7/8″ on the ground. I used 3 pcs of RG-217 for this with 7/16″ connectors. I also put the RG-17 for the 160m vert, 80m 4-SQ and 40m 4-SQ in the ground and routed them into the switching room together with the other coaxes.
Today it was rainy so I decided to build the verticals for the 40m 4-SQ. The tips were made out of an old ZX 15m monobander and I added some 31 and 35mm tubing to that plus put 12mm tips (tip of the ZX yagi was 15mm). This turned out great and hopefully I will be able to have them un-guyed since they stand rather well protected with forest all around.