Using a Municipal Flagpole for an Antenna – Fine Business!

Quite recently our local municipality replaced the weather beaten cedar flagpole at one of our local waterfront parks with a brand new one made of steel. During numerous visits to the park to enjoy the beautiful views of the big islands in Georgian Bay (Griffith Is, White Cloud Is and Hay Is), I have often wondered whether the new flagpole would make a good antenna. The flagpole is mounted on a concrete base so it is insulated from the ground. It might make a good vertical element, so I decided to give it a try. But a couple of potential issues had to be addressed before I did that.

First, what is the height of the flagpole? If it is not a half wavelength on any of the bands I usually use I could treat it as a fat random wire antenna. On the other hand, if it is a half wavelength I would need my 49:1 transformer. An eyeball analysis said it might just be a candidate for a half wavelength on 20m so I had to find out.

Second, how could I connect to the flagpole without marking or damaging it? I wanted to be a responsible amateur radio operator and besides, as a municipal taxpayer I figured I had a tiny bit of equity in that municipal asset.

Before making the 30-minute drive up the Georgian Bay side of the lower Bruce Peninsula to get to the park, I had to make sure I had the right gear available. Job One was to devise a means of connecting to the flagpole. Rummaging through my box of bits and pieces revealed a 3-foot length of webbing with a very secure military buckle on one end. The webbing had a grommet installed to secure the buckle. This would be perfect!

Using a quarter-inch nut and bolt and an oversized steel washer for a contact, a short wire was attached with which to connect my 4:1 unun to the flagpole. A 3-foot length of webbing would be sufficient to wrap around a flagpole up to nearly a foot in diameter. I knew from examining the base of the flagpole on a previous visit that its diameter was only maybe 6-inches or so. This bit of kit would do the job nicely.

When I arrived on site there was only one other vehicle in the park and a parking space near the flagpole was free, so on to Job Two – determining the height of the flagpole to see whether it is a half wavelength or random height.

I had learned a simple trick for finding the height of an object using nothing more than a stick and a tape measure. It relies on same very basic math, but no calculations are actually required. Find a stick that is the same length as your arm. I used a trekking pole adjusted to the correct length (yes, yet another cunning use for a trekking pole). Hold the stick vertically at the bottom end and hold it up – at arm’s length – in front of the flagpole. Now adjust your position on the ground until the stick appears to be the same height as the flagpole. Now measure the distance between where you are standing and the base of the flagpole.

The distance is equal to the height of the flagpole (give or take a few parsecs). Alright, it’s not very accurate but the technique does give a very good approximation of the height and that is all that was required for my experiment. My measurement in the park that day showed the flagpole is about 30 feet high. Hmmm, that is close to a half-wave on 20m. I had another trick to try that would confirm my measurement.

Feeling fairly confident, I hooked up my coax and laid out a single 28.5 ft ground radial – the same one I often use with my Rybakov antenna. The Rybakov uses a 28.5ft radiating element supported on a fiberglass pole. The flagpole antenna was very similar to my Rybakov and my LDG Z11 Pro automatic antenna tuner had the correct settings for the Rybakov stored in memory. If the two antennas were significantly different, the tuner would do a complete tuning cycle lasting several seconds. But, if the two antennas were very similar, the tuning cycle would last only a fraction of a second.

This was the “rubber hits the road” moment that would determine whether the day’s experiment would be successful. I set the radio to 20 watts CW on the 20m band and keyed up. Bingo, the tuner performed an almost instantaneous tuning cycle and gave me an SWR of 1.1:1. That was a relief. But, always keeping in mind that a dummy load gives a good SWR too, I needed to make a QSO to confirm the successful experiment.

I tuned in to a POTA activator calling CQ. He had a very strong signal and the noise floor out in the Big Blue Sky Shack was very low, making him a good candidate for a test QSO. I jumped in as he signed with a hunter and he heard me. I sent him a 599 report and he gave me a 579. My municipal flagpole antenna was doing fine business!

The park in which I was operating is not a Parks On The Air entity, but it is a very narrow park alongside a county road that forms part of the Great Lakes Waterfront Trail (VE-6003). Here was an opportunity to do an unplanned activation – a real test of whether my municipal flagpole was a practical antenna.

I posted a self-spot on pota.app from my phone and started calling CQ on 20m. Responses were slow in coming and by the time I had 8 QSOs in the log my battery voltage was showing some low numbers. I knew I had to do something to validate the activation with at least two more QSOs, so I switched to 40m. The flagpole again tuned up super fast and easy with a 1.3:1 SWR. Fortunately I was able to add another 10 QSOs to the log before deciding my battery may not survive much longer, so I called QRT.

And so it was a successful experiment. In all I made 19 QSOs with my municipal flagpole antenna and was very pleased. Now I have my eye on the much taller floodlight towers at the local baseball diamond. Will they tune up on 80m?

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