K0GKJ – Just Another Ham
The New QTH – A Floating Shack

Condo Beam is Up! Testing Soon!

Well, long time comin’, but the antenna is on the roof !

Still some adjustments to element wire and cord tension, as well as plumbing to better vertical orientation, not as high above metal roof as I’d like, but the ole MFJ-269 antenna analyzer will determine whether I’m having a SWR nightmare or a wet dream!

Probably something between the two.

She’s as high above the roof line as I dare go, even though higher is always better.

Life is full of little (and some not so little) compromises, huh?

 

Visible (as I had warned our homeowner’s board when they approved this installation), but not obnoxiously so (at least that’s my view!)

A view from nearby on the roof. Today’s task, assuming it stops raining, is to level the entire affair.

Crooked looks like crap, although notice I do NOT have the problem of TOO much tension in the wire elements. Quite the contrary, but ran outa time yesterday:

Since we live in hurricane and tropical storm country, I took a precaution that I saw on the hex beam forum–drilled and inserted a couple of “anti-windmill” bolts through each flange above and below the base plate.

Notice one straight head and one phillips head stainless screws below) above and below the base plate (which is laying on its side on the bench).

Used the hardware I had on hand.

I’ll do the same between the two four foot fiberglass pole mast sections:

Since I have a flat roof with no easy vertical access from the ground (for hoisting an assembled hex beam), I decided to assemble and test on the roof, which had its own set of problems (AND advantages). Here’s my up-the-ladder kit.

From left to right below, my trusty hardware and tool shoulder bag, baseplate/rotator/topmast assembly, center post, secondary mast section and assembled spreaders.

Once on the roof and carried the sixty paces to the mounting location, I disassembled the spreaders again for attaching to the baseplate (after marking them with my own simpleton-oriented numbers and arrows): 

Once on location, I used the electronic compass in my portable GPS to find north, marked it on top of the roof wall:

My assembly and test “stand” comprised tying the upper mast section to the lower mast section that is firmly mounted to the roof.

After afixing the center post firmly to the base plate, I needed to allow the base plate to “free wheel” on the mast to allow assembly since, at any point in time, half the spreaders will be suspended in mid-air.

This was one of the complications of not assembling this baby on the ground.

No big deal. I just rotated the base so that each set of spreaders was accessible either by standing on the roof or on a step ladder (which I also had to hoss up to the roof).

Now for my simpleton markings.

With six spreader assemblies, comprising three sections of different diameters each, with four sets of wire element connectors and one tensioning cord connector at the end of each spreader assembly, I needed to mark which way was up so that all wire element connectors were of the same skyward orientation as I started bolting the spreaders to the base plate:

Spreaders in place, with careful focus on equally tensioning all bolts so as not to deform the hex shape of the antenna support system:

Tensioning cords laid out. These are made of Kevlar (like bullet-proof vests) with a UV resistant Dacron cover with at least 700# pull strength for high winds. They connect opposite spreader tips to the center post which creates the basic “upside-down umbrella frame shape”:

Outboard ends of the first two spreaders connected to the center post – see the shape coming together? Cool! Note the step ladder necessary to reach the top of the center post:

and so on… you can see that there are at least two reasons why the bottom of this antenna needs to be elevated well above the top of the 5 foot high mansard wall.

First, to avoid nasty capacitative coupling with the metal roof. Second, head room for rooftop maintenance and inspection

If you’re not aware, check out Leo’s (K4KIO) awesome storm warranty at http://k4kio.com/warranty.html

A good weather-tight connection between center post and feedline with Coax-Seal molded around the joint.

Have you ever tried to remove this stuff after its been there for awhile? Sticky mess, right?

A trick I read about somewhere…

I first wrapped the joint with a non-sticky silicone tape that only sticks to itself, similar to a sailboat rigger’s tape (no adhesive residue on the joint) before wrapping with Coax-Seal.

When I go to remove it, no residue left on either the SO-239 center post connector or its mate, the PL-259 feedline connector!

Notice in the pic above I also clearly numbered each spreader since spreaders 1 and 6 have special significance for threading and tensioning the director and reflector wire elements.

Here are the wire elements, still in bags, to be strung around the perimeter of the “upside-down umbrella frame:

The wire itself is really where the action is. The rest of this stuff just holds it in place in the proper orientation. The wire is very cool stuff – PVC-insulated 14 gauge 168 strand copper flexweave, making it easy to handle. The insulation provides these actual antenna elements protection against saltwater corrosion.

A close-up of the completed assembly with tensioning lines connecting the spreader ends and four sets of wire elements installed. I opted for four bands–10M, 15M, 17M & 20M–not five–eliminated 12 meter so as to really get clean signals on 10M as solar cycle 24 fires back up. Plus, I ran outa moolah!

The pic below shows the view of the antenna from the roof of the front of the same building. You can see the distance the antenna (and the tip of a six foot step ladder for reference) is set back from the front of the building (the side that faces the rest of the buildings in our condo association).

Also gives you an idea of how visible (or invisible) it is.

This is probably worst case since the afternoon sun is behind the antenna to the west and southwest, causing it to be silhouetted against the sky.

Today, weather permitting, I’ll level the antenna, bolt the mast in the appropriate orientation for accurate and consistent rotatation with respect to points of the compass, test for SWR (standing wave ratio) with my antenna analyzer and then firmly bolt mast sections together so as to retain the desired orientation.

This should complete the HF portion of my installation. For more of the techy info on this antenna, check out http://k4kio.com/whatisahexbeam.html

To see what other hams are saying about this antenna, if interested, see http://www.eham.net/reviews/detail/8150

Bad news is that the roof gables themselves (under the mansard walls) are constructed of galvanized steel beams and vertical galvanized sheathing (the silver stuff).

The better news is that all  the roofing material itself is non-magnetic painted aluminum (orange stuff). So hopefully (ALWAYS hopeful!), not quite as bad an issue with antenna interference as initially feared. Tests with confirm or refute!

I’m posting this for my condo neighbors as much (or more) than fellow hams to give them a sense of what the skyward end of their association’s communications command post looks like from a view most all of them will likely will never see (from the roof).

Dear friends and neighbors, YOUR community radio station antenna should be an awesome performer !

right now I’m resisting the temptation to solder the PL-259 connector to the shack end of the feedline and test the SWR at this height above the roof, and to fire up the Icom 746 transceiver to see some on-the-air results. I’ve got another set of feedline noise suppression beads for this end of the cable coming from Ron Mott, which probably aren’t necessary, but can’t hurt, before I solder the final connection. I also need to clean up my feedline entry point before getting too far down range.

But its FINALLY comin’ together, folks!

Watch this space…

de (Morse shorthand for “this is”) K0GKJ (my amateur radio call sign)

dit dit (Morse for “LATER, ‘GATORS!)

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