Monday, September 03, 2012

The Summer Build Season & My 80 Horizontal Loop Antenna

As a newly licensed amateur radio operator, 2012 has been a long list of 'firsts'. Including my first summer of building, installing, and testing antennas.

My final summer task was a complete home-brew antenna project. I had already bought a couple other antennas (G5RV, Mosely CL-33 tri-bander, and Arrow VHF/UHF vertical), but I wanted to put in the reasearch and build something from scratch.

Over the last two months I have casually gathered, built, and made steady progress on an 80m Horizontal Loop that I completed just a few days ago.

Unlike my previous posts there isn't much to show (ie photos or videos) since a long wire antenna strung up about 30+ feet in the air is not easy to see, let alone with my camera. Suffice to say here is a description and I've climbed up the ladder one more time to get a couple photos.

Corner #1 - My 40' steel antenna tower attached to the house.
Corner #2 - My wooden antenna mast that I built just for this antenna. To build a horizontal loop you need to string it up in a square shape (or as close as you can get). I had anchor point on 3 corners of the property, but this corner needed something man made, so I built this mast.
Corner #3 & #4 are connected to two large Willow trees in the south-east and north-east corners of my property. Thanks to VE7SDV (Sam) for climbing both trees a couple weeks ago.

The 270' of coated copper wire is strung around all four corners in a rectangular shape. At each corner the wire passes through an insulator to keep it away from contacting ropes, branches, etc.

At the corner closest to my house a feed point was created using a plastic wheel from an old clothes-line. I drilled multiple holes to pass the wire through and secure the ends of the full length of wire. 450 Ohm ladder line was then soldered to the two ends. Tie straps secured everything.
The ladder line makes a straight vertical drop about 6-8 feet away from the roof and exterior wall of my house. It then slopes back into the wall about 6 feet off the ground and connects to this 4:1 Balun. 50 Ohm coax completes the run into my shack and antenna tuner.

So far this antenna has exceeded the performance of the G5RV. I did some switching back and forth and it appears to be better reception. Time will tell as I've only had a couple days to test it out.

I've also cleaned up the 12v power arrangements in the shack by wiring in a RigRunner 4010S switching power strip from West Mountain Radio and switching all the gear over to Anderson Powerpoles. I had to invest in a 2nd Weller soldering iron and a nice crimping tool, but now I have a large high wattage iron for cable creation etc, and a precise lower wattage iron to tackle circuit board work.

I must say the 4010S switching power strip is very nice. In the Auto mode I can leave the power supply and power strip turned on and simply hit the power switch on my radio to trigger an automatic power up of all the other connected devices (SWR meter, In-Line Noise Module, etc).

So as the title of this post states, my first summer as a licensed ham is nearing an end. And as I have joked with others, now I actually need to start using all this gear and antenna's and starting some serious DX'ing.

No matter what the upcoming fall and winter seasons have in store for the bands, I'm pretty sure I'll be ready :)


Ron VE7RLE said...

Good stuff, Aaren. I have much the same situation for a loop down the road some time when I get other things done first. I have a pulley up on each of three trees about 50-60 feet [done by a climber who was felling a bunch of danger trees, etc.] and I will need a fourth corner. This too may be somewhat close to a power pole.

I had done quite a bit of research on this a few years ago and found out that some lengths were suggested which permitted tuning on a significant number of bands with little chance of band conflict. Your figure of 270 is likely one of them.

I also have only one HF antenna and that is a G5RV. It was moved across the creek a year or so ago in a position where I have much better performance than I did when it was nearer my shack but on a neighbors property about 30 feet away. The neighbor was also getting a number of trees felled, including my G5RV tree which was on his property.
I would hope that my loop antenna would be significantly better than the G5RV for all the extra work it will take to set it up.

I imagine you have talked to Bill VE7KDK and you may not know that Robin VE7HMN has recently put up a full 160 metre loop with really good results. You might want to chat with him. 73 for now. TTYL Ron VE7RLE

AarenJensen said...

Thanks Ron for the comment on this post. I started with a G5RV and upgraded to the 80m loop. I do notice an improvement in noise levels but until I start making more HF contacts I won't know how well it does in all directions compared to the G5RV.

I wish my loop was a perfect square, but the shape I had to work with ended up being a rectangle with one end narrower then the other. Maybe in the spring I might try to "square it up" a bit more?