Using a tape measure and some very rough estimating, I came up with this plot of how the antenna is set up, without the ladder line in the middle (haven’t figured out how to add the feed line yet).
EZNRC antenna diagram
EZNRC antenna diagram XY
The far field plots EZNEC gives me look like this
80m
EZNEC far field plot 80m
40m
EZNEC far field plot 40m
20m
EZNEC far field plot 20m
10m
EZNEC far field plot 10m
The antenna model is pretty simple and nowhere near perfect. I’m probably missing a lot by not having the feed line included. Based on these rough simulations though, it looks like I’m warming a lot of clouds (ham speak for when your antenna is sending radiation mostly straight up).
Thanks to help from Dave/KF4FFO and Tom/AJ4UQ, the antenna is now hoisted up into the trees and plugged into the radio. I didn’t get a chance to grab my camera, but Tom had his to take pictures with.
Antenna raised
My Hyperdog ball launcher and 4 fishing weights with some lightweight line that Dave brought proved to be a very effective combination for getting rope and antenna up into the tree.
The arms of the antenna are arranged in kind of a tilted/rotated inverted L, with one side angled down and secured to shrubs at one corner of the house, and the other side nearly horizontal. Perhaps not an ideal configuration for this. Right now everything is secured with temporary knots. I’ll spend some more time making some adjustments to the antenna before securing everything down properly.
SWR tested with Dave’s Youkits analyzer showed pretty decent SWR and impedance at 20m and 40m (~1.7 or so), so-so at 80m, maybe usable at 15m and 30m with some tweaking and not so good at 10m. Since the antenna should be able to do 10m, there’s probably some adjustment that needs to be done with how things are arranged. I think I’m going to have to get myself one of those Youkits analyzers. They’re pretty slick.
Analyzing the antenna
Radio receives pretty well on 20m and 40m so far. I can hear the WWV time signal at 5 MHz and 10 MHz pretty clearly. Heard lots of CW and digital signals on 20m after connecting up the antenna. Need to test how well I can get out next.
Right now the coax feed line just runs along the ground, but I think I’ll look into routing it through the crawl space so that it’s not lying out in the elements and won’t get run over by the lawn mower.
Now an interesting exercise will be to figure out how to use something like EZNEC and try to model what the antenna is doing.
It probably won’t be until after Christmas before I can get everything up and running though. Still need to finish getting the office and the computer back into shape, then make room to set up the radio (which mostly involves finding enough flat surface space for everything). Then I’ll invite some friends over for an “antenna raising” and see about getting the shack operational.
That leaves the other side of the house, which faces a neighbour’s wooded property. With some assistance, I can probably get the antenna set up in an inverted V arrangement with the apex in one of the trees along the ditch. I just need to make sure the line stays out of the ditch and mark it so that the people who go through the ditches trimming back vegetation don’t take it out. I thought about maybe securing the ends of the antenna to the house, but that would put the antenna at an angle which I’m thinking would probably end up producing a less than optimal radiation pattern.
It’s too bad the tree behind the house didn’t survive the house construction. It would have been a great antenna mast.
I think for the first antenna at the house I’m going to go with the G0FAH/ZS6BKW variant of the G5RV multi-band dipole antenna.
It’s a simple antenna, a bit shorter than the G5RV with a slightly longer ladder feed line and from what I’ve read online about it, has pretty decent SWR in most of the ham bands I want to operate in.
I can either make one myself, which doesn’t look all that difficult, or get an already made one. Total cost ends up being about the same either way.
Still need to figure out how to put it up. There are some trees hanging over the ditch next to the house that have some sturdy looking branches that look like promising antenna supports.
There are a few constraints I have for getting the antenna up high: anything I use has to fit in the car and there’s a limit to the height I can reach easily. The power lines running behind the house also limits where I can put the antenna and supports. Maybe I can get some of the club members to come out and help me figure something out.
