I brought from the UK a bunch of “roach poles” (telescopic fibreglass fishing rods with no rings), a 2m parafoil kite and an enthusiasm for /P operating from beaches but for serious operating, it’s hard to beat the outstanding antenna farm at ZL6QH, now sadly in storage while a wind farm is constructed on Quartz Hill and surrounding high-spots. Rhombics, vee-beams and yagis galore, all gallantly installed and repaired by Brian, Wilf and other willing supporters at the club after the frequent storm damage (it’s known as windy Wellington for good reason!). 

Anyway, the first decent aerial I put up in Wanganui was a very simple quarter wave vertical for 40m (photo below). The roach pole is just high enough, mounted in a section of PVC pipe on a pole in the lawn, and doesn’t need guying - it just flexes nicely in the wind. The deer fencing rolls are now laid on the lawn with help from friends Kenny (right) and Scott (left) to peg it down with a few hundred 6-inch U-shaped ‘staples’ made of #8 fencing wire. Underneath the mesh are about 16 radial wires which couple inductively into the fencing wire. It works very well.

Towards the left of the photo above, you can just see some rope in a tall tree in the front paddock: it presently supports a multiband dipole (more below)

The antennas are selected from a home-brew switch unit in a sealed box inside a plastic crate (left) sitting behind those rolls of fencing. The box uses 6 lovely vacuum relays from Russia, and works very well, even better now that we’ve got the rain out of it! So much for being sealed.

I have a 7m steel tower and 3-ele tribander (Cushcraft A3S with 40m extension, but only one capacity hat left thanks to its adequate fixing method versus the other now in the shack). The tower is on a slight mound so antenna itself is at about 9m AGL - still too low for an HF beam which no doubt explains the poor performance but the other 7m section of tower won’t be added at this QTH:

The wire antenna barely visible in this picture is a multiband dipole. From the homebrew QRO balun, I’m running paralleled dipoles for 80m, 30m and 17m. The antenna is supported in two handy tall trees with the end ropes tensioned by hanging counterweights to allow for the trees to flex without snapping the wire.

There’s a second multiband dipole supported from another tall tree - a topband dipole inverted-vee with a 12m dipole in parallel.

This QTH is in a valley with nearby hills to the West, South and East and yet more off to the North ... which makes 12 & 10m QSOs something of a challenge. In a failed attempt to snag VP6DX on 10m, I drove to a local viewpoint and operated from the car using a 10m wire vertical on a roach pole jammed in the passenger door:

Unfortunately, condx evidently weren’t good enough due East to VP6DX though I could hear a beacon in Hawaii (North) at S9 and callers from the USA (North-East) at about S1. They went QRT shortly after. Still, I’m glad I made the effort and proved I can operate from a temporary location in an emergency. 

Antenna experiments

My grandad was a keen amateur photographer. He once told me “The camera is just a box to hold the film.  Worry about the film and the processing, not the camera, but the lens is what really counts. All the light that hits the film passes through the lens. Buy the best lenses you can and you won’t be disappointed.”

When it comes to ham radio, I’m convinced the same principle applies. The radio is basically a box that converts RF to AF. Worry about the receiver performance, maybe, but the antenna is what really counts. All the RF that enters the receiver is captured by the antenna, and all the watts that exit the feeder either heat the antenna and ground or head into the ionosphere. “Spend as much [time/effort/money] as you can afford on good antennas and you won’t be disappointed.”

My TS850s may be old but they are reliable, well engineered and easy to use. With a set of IRC CW filters installed in place of the Kenwood ones, they are plenty good enough for me. I’m working as hard as I can to improve my operating skills - that’s a lifelong challenge. What’s left is the antennas. Best of all, compared to the shiny new boxes being pedalled by Kenwood, Yaesu (now Motorola?), Icom, TenTec, Elecraft etc., antennas are cheap in terms of $$$ if not the time and land area required to install and tweak them. But that’s the fun bit!

There are several parameters to adjust when it comes to antennas but essentially the choices come down to gain (in both horizontal/azimuth and vertical/elevation planes, don’t forget) and pattern. I’ve had good DX results with vertical quarter-waves and inverted-vee dipoles, with reasonably low take-off angles and more-or -less omnidirectional in azimuth. I’ve never had tall enough towers at home to make horizontal antennas perform as per the textbooks (except in local contests where the high-angle radiation is useful) but even ground-mounted verticals seem to work fine.

I was tempted to try 5/8th wave verticals until I read W4RNL’s paper (one of many) modelling them against quarter waves and vertical dipoles. The improvements in gain and low take-off angle just don’t seem worth it.  I’m sure multi-element vertical beams would be better. 

The first experiment was simply to add additional wires in parallel to the existing 40m quarter wave, using the same coax feed and ground plane. I added 30m and 80m quarter waves - the 80m one makes an inverted-L.  They seem to work, after a fashion. I’m getting quite a lot of noise pickup on the verticals though.

Next I’m planning a 4-square, probably on 40m at first to compare against my current antennas. The design of the antennas themselves seems quite simple in theory: 4 x identical quarter wave vertical antennas each with identical earth mats consisting of at least 16 quarter wave radials, set at the corners of a square with quarter wave sides. Powering the antennas is also not too hard in theory: the front diagonal needs a negative phase shift compared to both diagonals, while the rear diagonal needs a positive phase shift. However, actually splitting the power and obtaining those phase shifts is not quite so simple in practice. 

There are basically two common designs: one as used in the Comtek 4-square box, and the other a W8JK design. W8JK criticised and improved the Comtek design, obtaining a bit more gain and a better azimuthal pattern with a reduced rear lobe. Given that direction switching will be more or less instantaneous with the right switching (so if I want to work someone off the back, I can just click the switch), I’ll go with W8JK’s design.

TK5EP has published a simple circuit for the 4-square phasing and control boxes, using 3 x DPDT relays and a 3-core control line (or 2-core bellwire plus the coax braid, maybe?). I created an Excel spreadsheet using textbook formulae and A_L values for various Micrometals powdered-iron toroids to confirm TK5EP’s component values for 40m, using textbook formulae (those shown on TK5EP’s website are incorrect). My calculations show T300-2 cores give exactly the right inductance and can handle more power than the T200 -2’s favoured by TK5EP. Now to find a source for T300-2’s ...