I can't exactly remember when I mentioned it, but it was some months ago during a discussion about 3 meter antennas.
It's nothing fancy, but works darn well especially when the tree squirrels decide to jump onto the weatherproof box and sit next to the radiator. Their tails flicker back and forth and I sit here in amusement watching the auto tuner bounce back and forth trying to compensate for the squirrels inductive influence!
Also comes in handy during the winter when snow is falling or building up. The next project for that system is installing a 10 watt or 20 watt load resistor to act as a heating element to help reduce ice buildup on the radiator. Got everything together to do the project but right now its 99+* outside and direct hot sun is something I try to avoid at all times, well at least prolonged direct sun.
I will start gathering up my notes and such and begin writing something on it. Maybe include some photos and maybe a little video.
RFB
Actually those two items were quite inexpensive. HERE are the gear reduced motor assemblies and HERE is the PWM control board, all from the same hobby engineering website. I use the bi-directional controller, first on the linked page for the PWM modules.
As you can see, these two items and a few more things such as a salvaged tuning wheel from an old radio attached to the gear reduced motor assembly, a salvaged tuning indicator band and spring, and the PWM controller and you have the basic building blocks for a remote tuned antenna. Go further by adding a sensing loop at the antenna, or nearby, and use that to feed a meter at your remote control panel for field strength indication/antenna peak indication.
All of this is assuming that an air variable capacitor is used for the tuning, like those found in the older style AM radios, which those variable caps are excellent for a 3 meter antenna system.
As we all know, the less amount of external influence upon the antenna system, the better it will tune and perform. I have considered using other methods like something mechanical moving a sliding rod or chunk of ferrite or iron. But that would put more potential for external inductive influence on the system or perhaps even throw it out of range all together. Size is another consideration for the "puppy hut" (outdoor box). What I was able to do with the above linked parts allowed me to put all this stuff inside the same box the TX already sits in, and still had room for adding the sensing loop, and even room for the proposed de-icer idea.
RFB
"Why not center load the antenna as in the case of "Bug Catcher" type antennas."
I actually did do this once and it does work a little better than a base loaded antenna.
Problem I had though is that Wyoming is renowned for it's wind gusts and overnight during such a high gust wind, the poor thing came down and tore a gaping hole at the top of the outdoor box. Fortunately it was not raining so the only damage was to the box itself and a busted up loading coil that looked like a fur ball of wire.
Carl mentioned in another thread that there never has been Part 15 AM tower disasters. 😉
RFB
When the Ultimate Radial Antenna gets setup out there I want every fancy device imaginable.
The voltage supply will be phantom delivered on the same cable with audio.
Want a remote tuning machine.
A tower search light, remote controlled.
A tower camera, pan and tilt.
Remote metering.
Remote power fine adjustment.
Temperature and humidity sensing.
100% disconnect at the house entrance during lightning.
Solar-powered with remote tuning via an R.C. car mechanism. STL from the radio control room. Signal strength meter at the control area for peaking. NO wiring to the house!
It is heart breaking that the sun does not hit the spot where there is enough clearing for the antenna system. There goes solar power.
But STL is a very attractive idea. OK.... put it in.
Sig strength meter....order one.
Wiring to the house will be needed for transmitter (power), search light, video camera, weather detectors, tuning junk.