TenTec
[Top] [All Lists]

Re: [TenTec] Resonant antennas

To: tentec@contesting.com
Subject: Re: [TenTec] Resonant antennas
From: Charles Greene <W1CG@QSL.NET>
Reply-to: tentec@contesting.com
Date: Sat, 04 Sep 2004 20:14:51 -0400
List-post: <mailto:tentec@contesting.com>
Ken,

What you say is true, and you can point out some good examples of antennas that are not resonant that work better, and extended double zepp, for example. But you have to qualify what you say. You need a low loss feed line, like a open wire feed line for example. Then you need a low loss antenna tuner, and you have to use it right. I have seen antenna tuners with a 3 dB loss. If you use a balun with an antenna tuner, it needs to be high efficiency too. For our last field day, we used a tri band beam, a 40 meter wire beam and a 135' Windom with a high efficiency balun at the top and fed with coax, which was broad band across 80, 40, 20 and 10. Nary an antenna tuner in sight.

W1CG

At 06:01 PM 9/4/2004, you wrote:
This is not a Ten-Tec specific topic, however.....

And, of course, he/she needs to know how to change bands and load the antennas (which ought to be resonant).
While there may be some reasons that it is "nice" or "convenient" to have antennas resonant, it is absolutely not necessary. I does not even make them work better in some instances, or significantly better in most instances. Yes, the transmitter should have a load which is not too far from being the right impedance and low reactance (50 ohms for most rigs these days) This can be accomplished using a tuner, making the antenna system (antenna, feedline and tuner) not necessarily the antenna by itself, resonant. Or it can be accomplished by using a wideband antenna, such as a discone or log periodic, that has such a broad flat impedance curve that it can hardly be called "resonant" at all. A lossy antenna ar a dummy load is another way, but of course not the best.

Ken N6KB


_______________________________________________ TenTec mailing list TenTec@contesting.com http://lists.contesting.com/mailman/listinfo/tentec

_______________________________________________ TenTec mailing list TenTec@contesting.com http://lists.contesting.com/mailman/listinfo/tentec

<Prev in Thread] Current Thread [Next in Thread>