A Question for the Antenna Gurus

[KG4CGC]

I'm wondering if you could get away with a single top loaded (coil) wire inside the flagpole. Possible have another wire drop from the top to about 1/4th to 1/3rd of the way down.

Then just for fun, a Slinky™ antenna inside the flagpole. Attach a wire to the end with a motor to pull and retract the Slinky™.

[W3WN]

Can't start it somewhere where you don't have property line issues?

Nope.

There's one Black Walnut tree on the opposite corner of the property, and it's all on my land... but it's a smaller tree, and it's about 20 - 25 feet lower (down slope). Down the road, that might be pressed into service. We'll see; I'm hoping that in a year or two, I'll be able to put a small utility shed down in that area & put a mast or phone pole or something back there, which I'll worry about then.

It's academic right now; the neighbors like us and don't mind the wire at all. And if it has to come down, in the future, well, I'll adapt. There's more than one way to rig an antenna... and I have some other ideas...

[W3WN]

I've used those 4-foot long, snap-together fiberglass poles to put up a 36-foot-tall support, with a 34-foot long wire taped to the outside of one side of the pole and about a 17-foot wire on the other side. I used around 10 radials of varying random lengths between 10 and 40 feet. I tack-soldered the coax to the ends of the wires and snipped off bits (and re-soldering) the vertical wires until the SWR was around 1:1 in the CW portions of 40 and 20 meters. The whole thing was bungee-corded to a sapling with a few guy wires.

A wind storm finally tore up the fiberglass, and it all came down. But it did work great for a couple years.

A year and a half ago I picked up some of the aluminum poles that match those fiberglass ones (the mil surplus stuff). The original idea was to use the fiberglass piece within the concrete as a base, and use the rest as the actual flag pole vertical. The boss wasn't too thrilled with the esthetics, and I really didn't want to strip the old Army green paint off of the aluminum...

Still have them, plus a could of rings that can be inserted within the system for guy wires. Not as high as the tree has the "L", but I'm thinking that in a pinch, it could be pressed into service as a temporary vertical.

I may just take the whole thing with me to Field Day and see what we can do. Or not.

[W3WN]

I'm wondering if you could get away with a single top loaded (coil) wire inside the flagpole. Possible have another wire drop from the top to about 1/4th to 1/3rd of the way down.

Then just for fun, a Slinky™ antenna inside the flagpole. Attach a wire to the end with a motor to pull and retract the Slinky™.

Probably, if it was narrow enough. I'm a firm adherent to the KISS principle, though, and I'm thinking that the less futzing I have to do, the better overall.

Physically tying some wires together isn't big deal. But when we start talking about coils or traps, now we're ratcheting up the complexity.

If this was a pure research project, I would give it a try. But this IS going to be a "real" flagpole, and once it's up, I'm hoping to leave it alone.

Again, we'll see. I'm at least a month away from putting it up, I have a lot of deck work to do first. But, that's why I'm enquiring now, so that when the time comes, I have everything ready (he says confidentally).

[KG4CGC]

You probably already know this. Anyone with black walnut trees on their property should know. They randomly drop large branches with no rhyme or reason. Sometimes dead limbs, sometime living ones. Go figure. I often expect them to break when we get a strong storm but no. Only during a clear still day.

[W1GUH]

Probably, if it was narrow enough. I'm a firm adherent to the KISS principle, though, and I'm thinking that the less futzing I have to do, the better overall.

Physically tying some wires together isn't big deal. But when we start talking about coils or traps, now we're ratcheting up the complexity.

If this was a pure research project, I would give it a try. But this IS going to be a "real" flagpole, and once it's up, I'm hoping to leave it alone.

Again, we'll see. I'm at least a month away from putting it up, I have a lot of deck work to do first. But, that's why I'm enquiring now, so that when the time comes, I have everything ready (he says confidentally).

The idea of top-loading it sounds intriguing. It's not mentioned much these day, but a top-loaded vertical will be more efficient -- something about current distribution before and after the coil. What's unclear is if the advantage makes up for the extra trouble.

[W3WN]

The idea of top-loading it sounds intriguing. It's not mentioned much these day, but a top-loaded vertical will be more efficient -- something about current distribution before and after the coil. What's unclear is if the advantage makes up for the extra trouble.

Certainly. And under other circumstances, I'd give it some serious consideration.

But keep in mind that the top sectiion of this fiberglass flag pole is relatively narrow. If I recall the specs correctly, the inside diamater is well under an inch. So I'd have to fabricate a very narrow coil, and then figure out how to snake it into the fiberglass intact, and then rig up a way to attach it. Impossible? No. Just more trouble than it may be worth for THIS experiment. But if it works out, well, there will be others...

[KG4CGC]

I figured you'd be able to open up both ends. You could always open it up and use a PVC cap. I'm assuming by your last post that the top is not open.

[W3WN]

I figured you'd be able to open up both ends. You could always open it up and use a PVC cap. I'm assuming by your last post that the top is not open.

Doesn't look like it.

[PA5COR]

Though you might have no other option as toploading with a coil, add some wire above that.
I don't like (top) loading with coils, i rather use top hats of wire.
Coils lower efficiency, lower bandwidth too.
No possebillety to run a thin wire from the top to a neighbouring structure?, make an inverted L out of it, introduce autotuner at the feeed point with as much radials as you can get in...