W5CPT wrote: "The author of the article claims an almost omnidirectional pattern at about 30 to 60 degrees. The mininec charts are in the book."... Don't pay too much attention to those Mininec plots
The answer is probably in the data you didn't give us. If this was an L made from something like #12 wire held up by a tree, it would be a very good match for 50 ohm coax, so about 1.5 SWR for 75 ohm
Thanks for the new data. EZNEC says that should be a good match for 75 ohm line. The insulated wire makes a significant difference. I can't imagine that you would actually have an SWR of 2.8. What ar
Mal I'm not Dennis, but I think I can answer your questions. The 175 feet number comes from the length required to get the resistive part of the feedpoint impedance of the L close to 75 ohms. The cap
It just occurred to me that I have two pieces of data that seem contradictory. Most people know that you can build a Ufer ground for a tower using concrete and rebar. The concrete is said by most peo
W7RH wrote: Further with the T portion as top loading the feed point radiation resistance will be greater for a given vertical height. This when coupled with an excellent ground system of 1/4 wave ra
Please disregard message below - sent to the wrong reflector - Jerry _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@c
I am looking for the best way to feed a 1/4 wave Vertical with the following in mind: 1) QUIET RECEPTION: will a tower being used for receive as well as transmit be quieter if the base is grounded an
Your last post came in just as I was about to send this one. I see you found something that lowers your SWR. I will go ahead and send this anyway, so you can see what was causing the problem. Assumin
It can be made to work (kinda) but not like shown in the figure. With a 130 ft dipole the two ladderline sections will have to be much longer, about 60 to 70 ft long each, depending on how close you
I would like some suggestions for a material to use for plugging the ends of booms and antenna elements to keep the critters out. I don't like using caps because those just trap the water inside. I h
I got several good suggestions, some bad ones, and some unknown ones. Here is a summary: - My comments are in parenthesis. Another note: Birds like to sit on the end of my boom and peck at these plug
In addition to the tower loading issue (which seems to be suspect), consider the torque issue. Antennas of this size can produce a lot of torque on a tower. That may require some professional help to
In that case, the tower will be severely overloaded. With the 80 meter 2 element at 18 ft above the tower and a MonstIR at 3 ft above the top of the tower, you will need a tower rating of about 60 sq
The company is the Hy Power Antenna Company, and the antenna you are refering to, I think, is the 3B4016L. Isolation coils is a term invented by the company. I think what they are doing is using a se
If you analyze one of these slopers in EZNEC, you can see why some people have good luck with them and others don't. The configuration that works the best is one in which most of the currents are con
EZNEC says that the shorty-40 at 90 feet should kill the vertical and the four square. The only angle where the four square has more gain is at 41 to 56 degrees elevation where the shorty-40 has a nu
..."I didn't tell the whole story about the 1/4 wave vertical: it's mounted 30' out in a saltwater river that has a pretty clear saltwater path to Europe, Africa, and South America. ".... There is a
A four square over salt water is very difficult to build. It almost requires a salt water marsh. If you have salt water available, you may want to check out the vertical phased dipoles that some of t
If you think about it for a moment, you should be able to see why you have the rfi problem and why the antenna is noisy. One half of your antenna is up in the tree. The other half of your antenna is