43′ Vertical Antenna Construction – Pt 1
43′ Vertical Antenna Construction – Pt 1
I’m looking for an alternate antenna for HF operation at the Ranch. I currently have an 80 meter doublet installed at about 30 feet above ground. That works pretty well with the balanced feedline, but I would like to have an alternative to provide some diversity.
So the thought is that I will install a vertical to complement the horizontal doublet. Perhaps when one antenna isn’t quite up to the job for a particular path, the other will be better. Verticals have long been recognized for their better DX performance, due to their typically low angle of radiation (at or near design frequencies).
My criteria is an antenna that works reasonably well on 160 – 6 meters, with low cost and low complexity. It should be self-supporting (even with our consistently strong wind at the ranch), and require little maintenance. Probably one of the most discussed antennas on the web today is the 43′ vertical. After reading many articles, I have decided to give it a shot. My design will strongly resemble the design of Phil Salas AD5X. He seems to have put a lot of effort into understanding how these work, and why sometimes they don’t.
There are several of these offered commercially by HyGain, MFJ, DX Engineering, S9, etc. Rather than by a kit, I might be able to save some money by home brewing it myself.
The basic design is 43 feet of aluminum tubing, mounted to a short pole at the base, isolated from ground. The other half of the antenna design is the radial system, which will initially consist of 32 #16 radials, each about 40 feet long.
While the antenna presents a reasonable impedance at 60 – 6 meters, it presents a very high SWR at 80 and 160 meters, due to its short length at those frequencies. So we will incorporate a simple matching network at the base, which consists of a coil with taps that can be switched into service at 80 and 160 meters. That will much improve the SWR at the far end of the cable, and in turn improve the overall efficiency on those bands (Not too much loss in coax due to high swr…)
So my first steps were to find the mounting hardware for the base of the antenna. It will sit on a PVC coupling to isolate it from ground. That coupling will be supported by a copper pipe going into the ground, and the antenna will be supported again about 5 feet off the ground to another PVC support connected to the mounting pole.
Here is the coupler for the bottom. It is a 2″ x 1″ reducer fitting. The 2″ OD aluminum tubing fits it it very well.
At the bottom of the reducer fitting is a 1″ x 3/4″ fitting to adapt to the 3/4″ pipe going into the ground.
And finally, at the bottom of the setup is the fitting for the copper pipe.
When it’s all put together, it will look something like this…
And of course, the bottom section of the antenna slides right in…
Continued Pt 2…
October 31st, 2010 at 10:38 am
How is the progress on the vertical? I’d like to see part 2.
October 31st, 2010 at 5:06 pm
Hi Lou. You may not have seen part 2 – 5 in later posts yet.
We installed the vertical for field day, and had some problems with the matching network. We ended up just using the 4:1 balun and using it on 40 – 6 meters for the rest of field day.
I have the matching unit on my bench now, and started trouibleshooting it this afternoon. After a few wiring errors were cleaned up, I still need to reinstall the matching network and finish testing.
Unfortunately, it will probably be nex spring before I get back up to the ranch to re-install it for a final test. The dirt road to our ranch gets very muddy during the winter, and it’s a little too cold up there for antenna work for this thin-blooded Arizonan.
Keep checking back, I have a few more projects to keep me busy over the winter.
73 de Randy WB0SMX
November 12th, 2010 at 3:26 am
Congratulations for your antenna
March 13th, 2015 at 12:45 pm
Hi Randy WB0SMX , I like to know how much power you are using with antenna, 1.5kw or 100w???? I HAVE 13.4M VERTICAL WITH 100W I TALK ROUND THE WORLD THAT IS WHAT YOU CALL ANTENNA , GROUNDED DIRECT TO GROUND WITH NO RADIALS , I HAVE VERY VERY SMALL SECTION 6′ ONE SIDE AND 3′ OTHER S
WHAT I AM SAYING THAT IF YOU HAVE TO USE 1,5KW AND ANTENNA TUNER IT IS NOT WORKING
March 14th, 2015 at 8:38 am
No worries, Frank. I’m only running 100 watts. I am off grid, so must generate my own electricity. High power would not be good for me.