Winter Field Day - 1/4w 80m Vertical
This is THE biggest antenna (electrical length) that I have ever set up! This was one of my two antenna ideas for Winter Field Day. The other one was a doublet with a balanced line feed. We had a G5RV set up that the other station was running on so there wasn't much of a point in me setting up another.
What I wanted to do was put together a vertical antenna that was made of some of the military tent poles that I have. The length wasn't critical as I wanted to try my LDG Z-11pro tuner in a remote configuration so resonance wasn't an issue.
It just so happened that I got within a couple feet at most of a full size 1/4 wave length on 80 meters! The total length of the antenna was just a hair over 69 feet. Each pole is 44.5" long and there are 14 of them. Then I had a 16' long crappie fishing pole way up top with a wire wrapped around it that was about a foot longer than the pole. All said and done there were 52' of aluminum poles and around 17 feet of crappie pole and wire on top.
The theory behind the crappie pole at the top is weight. The small fiberglass fishing pole weighs a LOT less than the aluminum poles. I made an adapter out of PVC pipe to attach it to the top pole. The mount for the crappie pole was very sturdy and it made raising the antenna much easier than if we had poles the whole length.
Speaking of raising the antenna - these poles made for quite a noodle of an antenna. We didn't think it was going to go up but we stuck with it. The pole bent a LOT on the way up. Once it was past 45 degrees or so it was a cake walk. Rex, W8WZZ tossed a rope through a tree and we used that as a gin pole of sorts so we could have a vertical component to our force vectors on the antenna. Before that the antenna was in no way going to go up.
It went up and it worked! For the rest of Saturday it was a bit breezy so the antenna swayed in the wind quite a bit. If I had a few more guy lines it would have been more stable. Overall it handled the conditions just fine though. I don't know if it would take a 50mph gust, but for our temporary set up it was adequate.
I bolted that PVC pipe in to the bottom section. I had made a 20m vertical antenna with these poles before and used a self-tapping screw and wire to load it with. That worked, but I just rested the bottom of the antenna on a piece of wood. In this case I wanted to make sure that the base was something that would hold firmly in the ground. I anticipated the antenna being a bit of a noodle so putting in the PVC insulator/base was the first thing I did. It worked great! Instead of putting the self tapping screw back in I just wrapped the wire around the bottom bolt. As long as it makes a connection that is all that matters.
The green radials are only 10' long. The black and gray ones are over 60' (they are elements for 4 direction a K9AY loop I had about 4 years ago).
Yes, the antenna is taller than the trees (most of them). You can also see how
the wind pushed it a bit. As I said, it is quite a noodle.
Here is the LDG Z-11pro tuner remote mounted. I put in an SO-239 bulk head connector through the box to make connecting the coax easy. I just drilled holes for the power, radiator, and ground connections. At some point I will probably put connectors on the outside of the box for quick connections and then seal up the holes. I don't want the tuner permanently mounted in the box, so having the normal connections on the tuner makes taking it out pretty easy.
My original plan was to run speaker wire out to the tuner for power. The Z-11pro can take internal batteries - with the addition of a (not included) battery holder. That would make things even easier, but I didn't have a holder. So I just put my SLA out there. That eliminated the long run of wire to power it. Since the tuner is RF sensing anyway you don't have to push any buttons - just key up and the tuner does the rest.
The bolt is my ground connection. This was a difficult assembly to get working. It would be so much easier to have ring terminals on all the wires... I just pinched the wires with the washers. It worked, but it took a while. You can also see my radiator wire that is on the bottom bolt of the pole. Nothing fancy.
This is the adapter from the poles to the crappie pole on top. I originally wasn't going to use that clamp. I thought that wrapping the radiator wire around the pole a couple times and then setting the PVC down on top of it would be enough for a good connection. The clamp probably was overkill, but there was definitely a good connection!
The blue rope is the one that goes to the tree (note the angle difference). This is what we hoisted up the pole with. The other three white ones are the normal guy lines. This is the same set of hardware I use for my VHF/UHF tower in EN39, on Field Day, VHF contests, etc.
This is the whole crappie pole. You can see the copper wire radiator wrapped around it. I just used cardboard to make up the gap between the pole and the PVC. It worked great!
The vertical would tune everything except for 160 meters. I will have to research this one and see what the deal was. 1/4 wave length on 80m is 1/8 wave length for 160m.
We weren't too competitive for this contest. It was a pretty relaxed "set up and have fun" event. However, we did make a few contacts. I don't know how well-known Winter Field Day is. We heard a few people calling "CQ Winter Field Day" but the contacts weren't flowing like they do during the real Field Day in June.
Another obstacle this weekend was the multitude of other contests running at the same time. The CQ WW 160m contest was this weekend. In my efforts to get the antenna to load on 160 I was amazed with how crowded the band was. I was not aware that the CQ contest was running this weekend. We got on the computer and looked to see what contests were this weekend. Ironically the CQ WW 160m contest is one of the largest contests - from an operator standpoint as well as, even more so, a heavily crowded band. It is a toss up between the CQ WW 160m and ARRL 160m contests as to which is bigger - both clog Top Band.
Maybe next year will be even more active! We sure had fun setting everything up and getting on the air.