My Rig & Antenna

When I got my licence back in the 80's, from then until early 2024 I used a Kenwood TS-140. It was a great rig, especially for QRPp as you could screw the power levels down to 1mW. unfortunately in 2024, the finals finally died, so it was time to look for a new radio. Looking around I finally decided on the Icom 7300 to use at home. Connected to my homebrew DX Commander (see below) via  a MFJ 813 QRP SWR/Power meter and a QRP Z match ATU, the Icom 7300 enable's me to operate at QRP 1 watt. To go down to QRPp levels (less than 1 watt) I use an attenuator when conditions suit. 

At home I use a Begali Pearl paddle (I love this key).
Previously was using a Straight key - a Himound HK 707

Homebrew DX Commander for 40/ 20/ 15 and 10m bands. 

Being that I already had a 10m squid pole, I looked around the net looking at various types of verticals, one of which was the DX commander. After a bit of research, I doing a bit of number crunching, I decided to model a 3 element version in EZNEC (antenna modeling program)  to see how the elements interact with each other (if at all) and also to see what the RF patterns would be like compared to a typical 1/4 wavelength vertical. After a bit of pushing and pulling the antenna, I was finally happy with the output. I then I modeled the antenna in AutoCAD, designing the parts to print out and then construction began.

First thing was the spreader plates which I made from some chopping board (HDPE) material from the

 $2 store. 

Next was the ground and element plate. I had an old 3mm aluminium BBQ cover plate tucked away in the corner of the shed, so I grabbed this. Bit scruffy, but after marking and cutting it out, I then polished it to bring it back to new.

I then dry fitted it all together

In the picture below, you can see on the table another ground plate. This plate I discarded because when I was bending the tongue, it was a bit to close to the element plate. Easier to make another one

My wire arrived from Jarcar, so time to duck down to the hardware store for some SS nuts & bolts, electrical forks, SS clamps and hose and some PVC pipe. Time to put it together

Here I took out the insert of the base cap and found that 40mm PVC pipe fitted perfectly inside the lower tube. So I cut a section of pipe 300mm or 1 ft long and inserted it

Next I had some 50mm PVC pipe, so I bought a cap to fit, marked the centre of the cap and then drilled and dremeled out a 40mm hole. I cut the pipe so that it was 300mm long, ground a chamfer on one end and pushed this into the dirt where I wanted the antenna to be. 

 Time to stand the antenna up for a dry run. Here you can see the antenna cap is now sitting on the PVC cap and with the 40mm pipe inserted into the pole itself and also the 50mm, this antenna base is rock solid and going nowhere

All Connected

Initially I only used the lower guys to steady the pole and I knew I would be dropping it down again and again with tuning the elements. 

End SWR result:

40m = 1:1

20m = 1.1

15m = 1:1

10m = 1:1

Radials... 9 bundles (4 radials per bundle) = 36 radials in total. Each radial is 10ft-7" ( 3.22m) long

Then it was time to drop it down again, install the upper guy lines and stand it back up. Rock solid in 25 kts winds. Just have to wait for my shock cord to arrive then its finished. 

Total cost to build?

$112 

So overall I was pretty happy with it. Later that day I cranked up 20m and made contact with Mark (VK3MJ) 1377 miles away on 5 watts (579 report) and a day later on 1/2 watt. Trying the rest of the bands on 5 watts I watched the RBN to see if I was getting spotted and saw that the USA/ Canada/ Europe and others were getting my signal. 

All in all.. very happy with the result. 

Catch you on the bands !