Sunday, December 12, 2010

With a little help from my friends, Part II

You might want to read Part I of this if you haven't done so already. It'll be a lot less confusing that way.

After we got the far-end rope over the correct limb, we tied off one end of the new G5RV and pulled it up in the air a bit just to make sure that we didn't run into any unexpected issues. That went well, so we moved to the near-end tree to attach the other end to that rope, which I'd lowered before David and Matthew arrived. We attached the other end of the G5RV to the rope and I started to pull it up, but the insulator at the end snagged on a branch and we couldn't get the antenna up nearly high enough. We dropped the antenna down to the ground and tried to use the rope itself as a kind of saw to see if we could break off the very small branch that was causing the problem. After about 5 or 10 minutes, we realized that 1) It was getting dark enough that we were having trouble seeing where the rope was going, and 2) The cold wind that had been blowing all afternoon wasn't stopping, and with the lack of sun it had gone from chilly to "ok, we've just about had enough of this" cold. It was time for plan B.

Several years ago, when having some work done on that "near-end" tree, I had the tree service put a pulley with some rope as high as they could up in the tree. I've played with it a few times trying some wire antennas, but hadn't used it at all for the last year or two. I figured that at least temporarily we could attach the remaining end of the G5RV to that rope to get it up into the air. If needed, Matthew could come back another time and try to get a rope over a higher branch with the potato gun, but there wasn't enough light to try that. (The reason why I didn't want to use the pulley permanently was because it wasn't all that high up in the tree, plus I didn't want to lose the use of that for any future experiments.) That worked out pretty well, and David, K2DSL, was nice enough to volunteer to head up to the roof to connect the antenna to the feedline. Next, it was into the shack to see if the antenna would load up (and to warm up!), which it did. I made sure that the tuner would be able to find a match as it had with the old antenna and was able to do so on all bands. By that point, we were all exhausted and cold, so after thanking Matthew and David they left. I did a little cleanup outside and headed in. I made one quick QSO (KP2B on 40m CW) just to make sure that the antenna actually worked, then headed out for dinner with Sharon.

The next morning I figured that I'd see what things actually looked like, and I was disappointed when I realized that the antenna was even lower than I'd thought. The pulley just wasn't very high up in the tree, and my G5RV was nowhere near a "flat-top" installation. I figured that I'd take a look at the other rope to see if I could do anything with it, hoping that perhaps "something" had happened overnight that might allow me to use it instead of the lower-than-expected pulley rope. It seems that I finally got a little break: I got both ends of the old rope and pulled back and forth to see if the resistance caused by that little branch was any less. As soon as I did, I saw a small piece of ice drop off from where the rope was wrapped around the branch, followed by a small piece of a branch. I think that what happened was that the rope rubbing the night before had allowed some sap to get onto the branch, which froze overnight and must have caused the branch to break. As a result, the little branch that was not allowing the insulator to move when pulled up into the tree was no longer in the way.

I dropped down the antenna from the "pulley rope" (which required me to toss the throw bag over the antenna wire, and carefully pull it down) and attached it to the older rope, and pulled it up. It took a little bit of work, but I was able to get it back up to nearly the original height. I spent about another 30 minutes more permanently tying off the ends of the rope, including connecting the ends to bungee cords that I use as shock absorbers before heading inside. I was able to make a few DX contacts on several bands, and in the week since then, I've actually picked up a couple of new countries on 80m (Iceland and Faroe Islands) as well as some new bands or modes for other countries (Congo on 20m phone and CW and 17m RTTY, Gabon on 20m CW, and Dominica on 40m RTTY, among others), so I guess the antenna is working well.

I'm still not very happy with the mechanical connections, and in particular, the connection from the ladderline to the coax feedline. I don't think they are nearly as sturdy as the antenna that I replaced, but I hope that what's there now will work out until the spring. At that point I want to replace some of what I think are the weak points with something sturdier. I may also look into other types of antennas, but for now, I'm very happy to be back on the air.

Thursday, December 09, 2010

With a little help from my friends, Part I

As I wrote about last week, my G5RV antenna came down as the result of a storm. My original plan was to try to repair the existing antenna, but after examining it further, I decided that I'd be better off buying a replacement which is exactly what I did. (I'll look at fixing the old one one of these days.) Matthew, K2NUD, and David, K2DSL, volunteered to come over last Saturday to help me get the antenna up in air, so we planned to meet at my house at around 2:30 which would give me enough time to run out to KJI Electronics to pick up the new antenna. The one that they had in stock from from MFJ and while it didn't seem to be build as sturdily as what I'd had in the air, I figured that getting some copper in the air was better than nothing.
Throw bag

The old antenna was suspended between two trees with the farthest end being at probably 60 or 70 feet in the air. (I'm terrible at estimating height, but I know that it's significantly higher than the roof of my house, which is at about 35 feet or so.) The antenna snapped at the far end, leaving the line suspending it about 50 feet in the air and somewhat tangled in the branches. As a result, it wasn't possible to get to that rope to re-use it, so Matthew came up with a better plan: a potato gun. The link tells you lots about potato guns, but in a nutshell, this is a gun made from PVC pipe that's used to fire a potato. (Why would you do that? Because it's unbelievably fun!) In order to get the potato to do something other than just shoot up in the air (and make a pretty cool sound), we put the throw bag which trailed 100 feet of line on top of the potato which worked like a champ.

The way the potato gun works is that you put the "fuel" (old-fashioned non-environmentally friendly Aqua-Net hairspray) into a chamber and ignite it which forces a potato, previously jammed down the barrel, up and out of the barrel at a pretty high rate of speed. In the picture here, Matthew (green jacket) is holding the gun while I spray in the "fuel" into the combustion chamber. That's David on the left. Somewhere out there I'm sure someone has done some calculations about amount of force that's being generated to launch the potato that far (not to mention the added one-pound throw bag), but physics aside, as I mentioned earlier, it's fun to watch.

It took a few tries, but Matthew managed to get the line over the right branch, which is a lot more difficult than it sounds. Although made somewhat easier by the fact that there are no leaves on the trees at this time of the year, it's still a lot like threading a needle that's about 50 feet away and 75 feet in the air. We came close a couple of times, but Matthew wanted to keep trying to get it exactly right, which I think was an excuse to fire off a few more shots. There's more to the story which I'll talk about in Part II, but here's a video taken by my son Justin during one of the "firings". (If you're reading this in an RSS reader or email and can't see the video, you click here to go directly to the video on YouTube.)

Thursday, December 02, 2010

Tree: 1 G5RV: 0

It was bound to happen sooner or later, but that doesn't really make it feel any better. At the edge of my backyard there is a tree that I was pretty sure had died (given the lack of leaves through the past spring and summer), and I'd planned on having a tree service look at it next  spring. A series of rainstorms with a lot of wind passed through my part of the world yesterday (I'll bet you can guess where this is going). One of the three small trunks from that dead tree snapped off about 8 feet in the air and fortunately fell parallel to my house so the house was OK. Unfortunately, my G5RV antenna passed through the upper branches of the tree and unsurprisingly was unable to withstand the force of the falling tree. The image you see to the right is a piece of one of the wire legs that use to be up in the air. It is, alas, no longer up in the air.

The force of the stress on the wire not only snapped one of the wire legs but also pulled hard enough to break the solder joints at the insulator where the bare wire connects to the ladder line, as you can see in the next photo.  Both ends of the soldered joint were broken, but the non-broken wire leg appears to be OK otherwise and is still attached to the "near end" tree where it was originally attached. The remaining few feet of the other leg appear to have snapped back after breaking and look to be up in the branches of the other supporting tree at probably around 50 feet in the air. I'm hoping that I can get a line over that and pull it down, since that way I can use the existing rope (which is still over a nice high branch) to support the replacement.

For at least the short-term, I am going to try to salvage what's there. Although this has been up in the air for over 10 years (I didn't think it was that long, but I realized that every HF QSO that I've made from my home station starting in August 2000 has been on that antenna) the other parts of the antenna seem to be in fine shape. (And it was certainly working very well until it came down.) The G5RV is, without question, a compromise antenna, but in the 10 years that I've been using it  I've managed to work all states, all zones, and gotten DXCC on all bands from 10m to 80m (I still need a few more confirmations for 30m) and on all three modes, and have worked 300+ DXCC entities using this compromise. Would I like a tower with a nice Steppir on it? Sure, but that's not happening anytime soon, so I'll stick to what I know works. I have another G5RV that a friend gave me before he moved out of the country, and while I need to verify that the wire is the correct length, it's been sitting in my garage out of the elements and the wire legs look like perfect candidates for a "transplant".  The big advantage of repairing what's there is that it will be zero cost and with a little luck, I should be able to get it done over the weekend.

If I can't repair it for whatever reason, then most likely I'll run over to KJI Electronics and pick up a new one and put it up in the same place. I have discussed with some friends the possibility of replacing this with something like an Alpha-Delta DX-CC or possibly even an Alpha-Delta DX-LB Plus (I have the horizontal room, the question is whether I can get it high up enough to function properly), but for now I think I'm going to stick with what I know works.

I hope to have an update with good news soon, stay tuned.