Vertical Antennas and Carbon Fiber Masts

I found out this morning that carbon fiber masts are not ideal for mounting vertical antennas. The carbon mast acts as a conductor, (allbeit a poor one), and that throws off the resonant point of the antenna. At least that's the story on the ham radio streets.

One day, I'll try a fiberclass mast to do a caomparison. As mentioned yesterday, our POTA came off without a hitch and with nice signals all around that were comparable to or stronger than the levels we normally get out of Project TouCans. I'm documenting our setup here so we can easily compare it to future deployments and so that others trying the similar things can use the information.

Here's a picture of the setup.

The wire was taped to the mast using electircal tape, with one piece of tape per mast segment. The mast was secured to the edge of a wooden fence using tarred twine.

The rig, (Project TouCans is a 20 m RockMite feeding a Tuna Topper II powered by am Imuto phone charging brick providing 15 Volts DC through a USB-C connector), was laying on it's side on the dock. We usually use it as a dipole setup with the rig suspended in the dipole, (second picture), consequently, we ran one side of the 'horizontal' dipole up the mast and immersed the other side of the dipole at ground, (the seawater about 1.5 meters below the dock.)

The red buckle for the canvas backpacking safety strap that holds the rig together, (it's made from three cans, a pineapple can holds the rig and Tuna Topper amp, the tuna can that W1REX shipped with the Tuna Topper serves as the antenna mount, and a soup can holds the battery), can be seen in both pictures so you can get a feel for how things were arranged. The Raspberry Pi Pico-W that serves as a Wi-Fi control for the rig's on/off latching relay and keyer can be seen mounted on the side of the rig, but I digress because this is supposed to be about propagation, so...

And here's a look at the propagation. We were spotted pretty consistently in Australia and once in New Zealand.

I've also added a closer view of the North American RBN spots, (red markers), and QSOs, (blue markers.) The colors of the paths indicate their relative signal strengths. The color coding uses the resistor color code, so for QSOs white indicates a 599 while red and orange represent 229 and 339 respectively. For RBN spots, all dB levels are compared to 40 dB, (a number we thought TouCans would never reach), and white is the highest color level there as well.

I was surprised by how well the antenna worked. It did better than our dipole did at that location and the numbers from the RBN were better than or comparable to the numbers from the dipole when mounted at the house across town.

I'd love any thoughts on what was going on, because KO6BTY and I are completely new to vertical antennas.

One last note on broadcast station rejection. When we turned on the rig yesterday, all we could hear was a local AM station. After I transmitted the first series of CQ calls, the station was mostly filtered out and could only be heard very faintly in the noise. We've seen this happen before with TouCans. Something in the rig seems to get 'charged' and that gets the RF in filtering to be more effective.

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Copasetic Flow

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