Inflatable antenna tower

[LtCmdLeia]

http://ltaprojects.com/ham.html

OK these are cool, portable, inflatable, antenna towers, from 25 ft to 60 ft. They would be fantastic for emergency situations where you need to set up a communications base.

[KJ4VOV]

Personally, I think they'd be of very limited use in emergency situations. They're only rated for 30 mph winds, can only lift 5lbs, and require a constant 5.5amps (660 watts) of 120v power. In a true emergency you're likely to be running on battery power, and even with an inverter to provide the AC you're going to deplete your batteries pretty fast. And I won't even get into what kind of RFI that cheap blower motor will generate...

In many scenarios you'll also be dealing with winds in excess of 30mph (hurricane, tropical storm, etc.). And that lift rating means getting your antenna, balun, and coax up could be a problem (assuming HF operation with something like a Carolina Windom). Also, while it supposedly can handle 10lbs when inflated, how do you get your antenna up there at that point?

For 2m/70cm you're going to be pretty limited on antenna choices, probably to just a roll up J-pole. Forget anything like a copper cactus or aluminum J-Pole because getting to stay vertical on top of that is going to be neigh well impossible, and the same with any kind of beam because it won't support a rotator.

Instead, military fiberglass cammo poles can be had for as little as $7.50 a dozen on eBay (plus shipping of about $25) and will support just about any antenna or antenna/rotator combo you'll want to use, don't require any power at all, and can survive much higher winds with minimal guying.

[TacAir]

An/GRA-4 mast, antenna. 40 foot. Poles are Al, metal being less sensitive to the cold..

At 85 pounds, not something you would backpack, but I have used them from the arctic to the desert and they have never failed to work. WIll hold an HF wure and, can be used as a verticle and you can mount a V/UHF beam at the top for all band commo.

Price varys on condition.

[KJ4VOV]

Each has its good points and its bad points TacAir. The fiberglass masts, while not as strong as the aluminum, and brittle in really cold temps, have a weight and cost advantage over the aluminum and, of course, are non-conductive. In a perfect world, I'd have both.

[MaconCJ7]

I'll stick with the Al GRA-4 if given the choice. The fiberglass really doesn't handle abuse very well, nor direct contact with the elements for long periods of time. I've seen the fiberglass ones shatter from stress on more than one occasion. I've also put up the Al ones that were bent to shit, but held up perfectly. I no kidding had a GRA-4 that looked like a crooked river, though the top was perfectly in line with the bottom.

Now, if I had to choose between fiberglass or the inflatable, I'll take fiberglass. The inflatable one is a neat idea, but the possible problems are too numerous to mention. The KISS principle comes into play on that one, and the GRA-4 system, no matter the material, wins.

When it comes to land required for raising the mast, the inflatable one does win out, since it requires no guy wires. Aside from that, I see it as a very niche market, and not for the light of purse.

[KJ4VOV]

I'll stick with the Al GRA-4 if given the choice. The fiberglass really doesn't handle abuse very well, nor direct contact with the elements for long periods of time. I've seen the fiberglass ones shatter from stress on more than one occasion. I've also put up the Al ones that were bent to shit, but held up perfectly. I no kidding had a GRA-4 that looked like a crooked river, though the top was perfectly in line with the bottom.

Now, if I had to choose between fiberglass or the inflatable, I'll take fiberglass. The inflatable one is a neat idea, but the possible problems are too numerous to mention. The KISS principle comes into play on that one, and the GRA-4 system, no matter the material, wins.

When it comes to land required for raising the mast, the inflatable one does win out, since it requires no guy wires. Aside from that, I see it as a very niche market, and not for the light of purse.

Actually, if you read the specs on it it does indeed require guys.

And yes, if I could only pick one system it'd be the GRA-4. The fiberglass poles have their drawbacks, no argument there, but when you can get a dozen for less than ten bucks they're pretty cost effective.

[MaconCJ7]

Actually, if you read the specs on it it does indeed require guys.

And yes, if I could only pick one system it'd be the GRA-4. The fiberglass poles have their drawbacks, no argument there, but when you can get a dozen for less than ten bucks they're pretty cost effective.

I did a quick read through the specs, and didn't see any in the pictures. But you are correct, they are required. IT looks like they follow the body though, and don't run out like typical guys.

I've never looked into private purchase of the GRA4 kits. Didn't realize they were that cheap. By all means, press on with your bad self.

[KJ4VOV]

Actually, if you read the specs on it it does indeed require guys.

And yes, if I could only pick one system it'd be the GRA-4. The fiberglass poles have their drawbacks, no argument there, but when you can get a dozen for less than ten bucks they're pretty cost effective.

I did a quick read through the specs, and didn't see any in the pictures. But you are correct, they are required. IT looks like they follow the body though, and don't run out like typical guys.

I've never looked into private purchase of the GRA4 kits. Didn't realize they were that cheap. By all means, press on with your bad self.

The GRA4 kits are not cheap, if you can even find them. But I've purchased three kits of fiberglass poles (12 poles + bag) now for $7.50 per kit. Okay, the shipping was a killer, at about $20 per kit, but it's still far less than you see them going for at hamfests, and the next time I'm up in that area in NY where the seller is located I might just pick up a couple dozen more kits for use by our local radio clubs and emcomm team members.

[zommoz10]

I agree that it'd be pretty worthless in most disaster situations but I still think it's a pretty cool concept. Of course if you went putting up what looked like a smoke stack in this area, you'd end up on the 6 o'clock news.
They should make a bounce house for hams and call it a mobile command center. At the very top, like a minaret, would be the tower. That way it would be weighted down in the wind. It could then be inflated with hot air and have enough lift for the largest antennas.

[TacAir]

Actually, if you read the specs on it it does indeed require guys.

And yes, if I could only pick one system it'd be the GRA-4. The fiberglass poles have their drawbacks, no argument there, but when you can get a dozen for less than ten bucks they're pretty cost effective.

I did a quick read through the specs, and didn't see any in the pictures. But you are correct, they are required. IT looks like they follow the body though, and don't run out like typical guys.

I've never looked into private purchase of the GRA4 kits. Didn't realize they were that cheap. By all means, press on with your bad self.

I dumped 4 of the GRA 4 kits and several R-390s before we moved back to Ak - the shipping was just too killer. The flea market mavens were pretty happy...

Now I just use a BTV series trapped antenna...

[Commo141]

There are a couple of telescoping flag poles that are being used for antenna masts.

[KJ4VOV]

There are a couple of telescoping flag poles that are being used for antenna masts.

Yup, and some of them work fairly well too. We were just talking about those before the local ARES net tonight.