[TowerTalk] verticlas used on multiple bands fed with a tuner

[Steve Hunt]

Mark,

I guess a couple of considerations would be the variation in radiation 
elevation pattern and the feedpoint impedance - can the tuner handle it?

If we take as a benchmark a quarter-wave vertical over a moderate ground 
system (5 Ohms), the vertical could grow to over 3/4 wavelength long 
before the low angle radiation dropped below that of the quarter-wave. 
In other words, a fixed length vertical that was a quarter-wave long at 
the lowest frequency should be fine over at least a 3:1 frequency range.

To minimise the chance of matching problems you would probably want to 
avoid half-wave lengths or multiples.

43ft seems to be a popular choice and avoids some of the most difficult 
impedances, but the elevation pattern above 17m begins to look poor for 
DX work.

73,
Steve G3TXQ



On 14/11/2011 15:00, Mark Beckwith wrote:
> Re: vertical antennas you can use on multiple bands with a tuner, are there magic lengths?  I would just as soon put up one for "the low bands" and one for "the high bands."  Or whatever.  I figure the answer has already been determined long ago and I don't feel a particular need to discover it myself is someone can just tell me what the prevailing wisdom is.
>
> Thanks in advance,
>
> 73 - Mark, N5OT
>
>
>
>
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