Ham Radio Tower

[GaryM]

Well Pat, it's like this.

Pro:
No climbing required.
Cheaper than a self supporting tower for the same windload rating.
Won't rust.

Cons:
Guys must be slackened to raise or lower a beam antenna. Not good on a windy day. Generally not good to climb on a windy day anyway so this might not be an issue.
If the rotator fails you may not be able to orient antenna to clear the tower structure.
Can't sidemount antennas for fixed orientation.
Can't use an antenna with elements spaced closer than the width of the tower. At least near the boom to mast mounting area.

I still have two antennas to mount. All that's up now are a VHF/UHF vertical and a VHF/UHF beam. After the holidays we'll mount the 6M and HF beams.

[Pat]

Gary, I guess it isn't a real straight forward slam dunk one way or the other, is it?

Your negatives seem to be nearly gaining the advantage but that is from over here with zero hands on experience with your tower. I just don't know for sure what I will do but it will be a while before I get to do it. I'm still hopeful I'll find something like a small oil derick but it isn't all that likely anymore. I need good wind resistance and would love to be guyless but who knows what a rigorous analysis will show as I haven't done it yet.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[GaryM]

The Boeing ARC in St. Louis has a 72' US Tower. It's a four section crank up (electric of course). It's about 23' tall when retracted. And heavy duty! It's set in a concrete cylinder 5' in diameter and 12' deep. Rebar in there too.

The hole was done by a big truck and auger. They made the hole in about one hour. The Boeing facilities folks had made a curved rebar cage that was suspended in the hole. And a nice masonite ring form around the top to make it look real pretty. Of course the mounting bolts were suspended in there too. I think there's something like 40,000 pounds of concrete in the base.

We let the concrete cure for a month and bolted on the base. Then used a fork lift to attach the tower itself. Mounted the rotator and mast, as well as the VHF/UHF antennas. Cranked the tower vertical and bolted it down to the base.

Then we used a bucket to add the other antennas.

Tower goes up and down very nicely.

Tower photos available here: http://www.qsl.net/w0ma/gallery_tower.htm
and here: http://www.qsl.net/w0ma/photos/shack/sh03_12.htm

I would have loved to have one of these, but The tower and installation probably cost Boeing $10K or more.

[Pat]

Gary, What used to be NEL or NELC, the Navy Electronics Laboratory, Point Loma (in San Diego) before it merged with some other sets of alphabet soup and finally ended up as part of SPAWAR (no, nothing to do with splashing water in a hot tub) Space and Naval Warfare center, now moved from DC to San Diego. Anyway, the old NEL had a huge crank-up tower topped with a MAGNIFICIENT log periodic. The boom was of such length with a triangular cross section such that it could have made a substantial tower on its own had it been erected. I don't recall the number of elements nor the length of the longest but it worked with low VSWR from almost DC to daylight. OK, maybe not quite that broad.

The good part was that there was a Pt Loma Amateur Radio Club with access to the MONSTER antenna during off duty hours if it wasn't tasked for anything else. All employees were eligible to join. We had a veritable antenna farm up there atop the ridge which constituted Pt Loma (not to mention the million dollar view of the ocean to the west and the harbor and entry channel to the east. Oh, The navy surplus amps could be with some dilligence throttled back to legal input power.

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[GaryM]

One of the Boeing clubs on the West coast had a similar setup. The Log Periodic used sections of Rohn 25 as the boom. They don't have it anymore, but did about 2 years ago. Maybe it was the same one. They also had some Navy or Army amps. Could it have been Seal Beach?

[Pat]

Gary, The location of the antenna to which I referred was definitely on Point Loma near the Cabrillo National Monument in San Diego.

I am not aware of the circumstances of any of the Boeing clubs, even in SOCAL.

Hey, your from California do you know ____ or did you ever see ___ . Fill in the blanks with names of movie stars or obscure family member of the questioner who doesn't "GET IT" as regards population density in SOCAL.

Also I like... "Oh, a ham radio guy, huh? how often do you talk to my uncle ____, he's been one for years, got the most powerful CB in the county.

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[GaryM]

Hey Pat.

Back from Florida. Prius used 28.7 Gal. to drive from Warrenton MO to Ft. Lauderdale FL. Just under $50 worth.

On the antenna, I'll have to ask our club trustee where that big LP was located. He's the one who was telling me about it a few years back.

[Pat]

Welcome back. Can't comment on your fuel consumtion/expense as I don't know the miles but it seems pretty good.

I was wondering if there was much ham involvement in passing disaster traffic after the quake/tsunami. I feel cut off from all that since I have been out here and haven't got a good HF situaton set up yet.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[GaryM]

1260 miles.

Probably lots of local and area usage of ham radio involved. I get all the ARRL newletters and announcments via e-mail and there has been no notice about frequencies set aside for health and welfare traffic. This is usually done for hurricanes and other similar situations.

As I have not got my HF beam mounted yet I've not been able to monitor any HF traffic.

[GaryM]

The 6M and HF antennas are finally on the tower!

This photo shows us moving the HF antanna from the assembly area (garage apron) down the hill to the tower.