Antenna Opportunities

I am still pursuing aluminum (aluminium as they say it here) tubing with which to build a log periodic antenna. We spent an entire day chasing down sources in Kampala. No one, NO ONE, has any. We checked all the metal suppliers and importers, all the manufacturers using aluminum components, anyone that might have a connection to or supply of the stuff. We found plenty of square tubing, the type used to make windows, but no round tubes. We did find one importer who claims he can bring it in from neighboring Kenya, and is supposed to be doing so this week. I must confess I am not optimistic.

I have checked on the price of bringing in one from the States. Tennadyne manufactures one I like - their T6 model. The price is $506 plus shipping. FedEx charges are $428 (all prices are US dollars) which will also take care of customs charges. That adds up to $934. There is another method of getting it here. I am returning to the US for a few weeks this summer. I could order the antenna and have it delivered to my US address. The antenna comes in a 6" X 6" X 72" box and weighs 65 pounds. If I bring it back with me I will have to pay for an extra piece of luggage plus excess weight. The cost? $200. Then there is the challenge of getting it through customs at the airport once I arrive back here in Uganda.

Ordinarily customs is no problem. But the customs people, if they are on duty and in a frame of mind to be responsible, target incoming boxes. If they stop me, it will certainly mean extra duty charges and maybe a tip (wink, wink) to the agent. Add up the freight to have it delivered to me in the States, excess baggage and weight charges, import duty and tip and I get very close to the cost of just shipping it here. I have been completely blindsided by the unavailability of round aluminum tubing. I never considered that no one in the country would carry it. I did find a small supply of one size I need at a department store in Kampala. They were selling it along with TV antenna kits. But their supply was small, not enough even to fulfill the required quantity of the one size,  and they had none of the other sizes I need.

Steve Bunting, M0BPQ, sent me the links to specs for building a Spiderbeam clone, another design I like. I had considered this before I left the US. There was an article in QST last summer about building one. It is easy to build and lightweight. However, I have since discovered that fiberglass poles are harder to get here than aluminum!!

When I came here this past October, I brought a Hy-Gain AV-18VS multi-band vertical with me. I used this antenna at my shack on St. Croix in the US Virgin Islands when we lived there. The shortest piece was almost 5 feet long. Well, my largest suitcase was no where nearly that long. I did not want to pack it in a box for the reasons stated above so I took a hacksaw and cut the pieces in half. With the longest piece now under 30 inches, I bundled them together and packed it inside one of my bags.

Putting it back together here using hose clamps didn't go precisely as I wanted. Making pieces fit took some adaptations but it is together and installed, albeit a little bit shorter than it was in the islands. It is, however, a little crooked. I erected it on a wooden base set on the intersecting peaks of the two wings of the office building I work in. I installed 4 guy wires and ran a ground wire from the ground terminal on the antenna base to a copper rod in the ground. The wooden base insulates it from the metal roof, which serves as a radial system for the antenna. There is a tuning coil on the antenna which I permanently tuned to the 20 meter band. With my MFJ-974 antenna tuner in the shack I get a SWR reading of 1.1:1. I get very good signal reports and am quite pleased.

Many years ago Swedish missionaries developed this site, having arrived here to rebuild school buildings after the exile of Idi Amin to Saudi Arabia. They were apparently amateur radio operators too because they left behind an old Yaesu radio and a folded dipole antenna strung between a water tower and a mast. There is a coax feed line which descends from the antenna then disappears into a wall never to re-emerge anywhere. I intend to run a new line and use this antenna too. It is approximately 66 feet from end to end. Double that because it is folded and the full length is 132 feet or thereabouts. That makes it resonant for 40 meters. The Tuna Tin 2 I built is tuned to 40 meters so I plan to connect the beacon to this antenna and just see what happens. The antenna had become twisted requiring the installation of a new support line. It helps to have a crew of natural pole climbers here at the project. One of them, photo below, shinnied up the pole, removed the old line, and threaded a new one through the ring at the top.

But I would like to put up a log periodic antenna on a 40' tower eventually. How that will work out is still a matter of speculation. There are lots of metal shops here and iron components are not hard to get at all, so I can have a tower made. Galvanizing the iron is out of the question. I'll just have to keep it painted but then again labor is inexpensive. The tower plan I have ordered (I found a copy of the booklet through an Amazon used book seller) - and should arrive today courtesy of a visitor from Boston - is a design by the late Dave J. Gingery. He put together a plan for building a 35' tower that pivots in the center, making climbing unnecessary. (Good for me. I dislike climbing stairs and am quite adverse to climbing a tower.)

If this were a place with zoning restrictions and building codes I might have a challenge getting a design like this approved since there is technically no certified engineer's signature for the plans. But, Uganda is not so structured as yet.

It seems now that gathering the balance of the necessary components - rotator and controller, more coax and connectors, the antenna itself, antenna switch, and the like - may take a little time. Nonetheless, I could have everything in one place by September or so when I return from the US. I will be in the market for an amplifier for the shack and open to your suggestions as to which is the best. Just remember I have to carry it in a suitcase, not a box, and there is a 70 pound weight limit. All the QRP'ers who read this blog, fear not. I have not abandoned QRP. I hope to work on the next component in my QRP beacon project this weekend.

Until I get all the pieces, the misshapen vertical antenna seems to work just fine. I worked A41NN in Oman again yesterday and RD3ZV in a community near Kursk, Russia. I'll let you know how the folded dipole works out when I get it connected.

 

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