Drainpipe Vertical Antenna

Paul, G3SXE, describes a project carried out during his recent trip to Florida (W4). He set out to prove the old radio ham saying that anything metal can be made to radiate a signal.

I searched around the garden where I was staying and found a length of hurricane damaged down pipe, and an old flower pot. In the garage I found 3 earth securing screws that were used for keeping an outdoor Christmas decoration in place and some old radial wires that I had in my radio box that I keep out there. The plastic pot plant draining tray came along later.

In the picture below you can just about see the various items for my project. The down pipe is made from thin aluminium, the plant pot just fitted into the base of the down pipe to act as an insulator. The down pipe itself measured 11 ft ( a quarter wave on 15m).

The parts of the antenna

The whole structure was supported vertically by three pieces of nylon string and base insulated only with the plant pot. My first attempt at tuning up the beast failed miserably! It just would not tune either with an ATU or without. The problem was the plant pot… it was porous and only presented a measly 200 ohms DC to earth. So another chase around the garden and I found the plastic pot plant draining tray. I placed the tray between the plant pot and the grass and of course the problem was solved.

The top of the drainpipe, supported by nylon guys

Because the diameter of the pipe was large, the ‘antenna’ was very broad band. On 15m it was a perfect match! It had very usable SWR of 1.5 :1 on 20m and the same on 10m. It was beginning to look as if there was some truth in the old adage...

The base of the drainpipe showing the plant pot insulator

My first 20m contact using this contraption was on 22nd March at 2125UTC. It was with 5B4AJC Alex, in Paphos, Cyprus. As you can imagine I was very pleased with that result as I was in Florida near Miami and was only using my elderly FT747. I went on to have many more QSOs with this antenna. The only draw-back was that I could not leave it assembled for any length of time; I had to disassemble it whenever I finished using it otherwise the residents association may have taken a dislike to it!

Log entry using drainpipe antenna

I tried a selection of different antennas on this trip, including an inverted ‘V’ and half square, both for 15m. Pictured below is the end of a 100ft Long Wire which was up about 20ft. No matter what I tried during this trip the propagation just did not allow me to put a usable signal into the UK and contacts were only possible if the UK station was using a beam and running the legal limit

Long wire antenna

Let’s hope for better luck next time!

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