[Elecraft] [KX3] Re: Strong recommendation: MFJ 18xx-series single-band whips for KX3, etc.

[John Pitz]

Hello All,

Please excuse the amateurishness of this question, but could you get one
of these whips for a low band such as 40M and use it on say 20M if you
don't extend it fully?  

John Pitz
KD8CIV



On Wed, 2016-03-23 at 22:02 -0700, Wayne Burdick wrote:

> "Walter Underwood wunder at wunderwood.org [KX3]" <KX3-noreply at yahoogroups.com> wrote:
> 
> > I got the whip for 17m. I figure there is not much difference between a coil at the base of the whip and a coil inside the ATU. Neither one will radiate. So get a whip for the highest band you want to use and let the ATU provide loading for lower bands.
> 
> That is not my experience. A high-Q loading coil, combined with the whip, is resonant near a given band and provides much lower loss than a whip of the same length with no coil, matched using the internal ATU. So while the ATU *can* match the whip on bands other than the design band, the farther you get from the design band, the greater the loss. 
> 
> That said, a 17-meter whip is a good choice if you want to occasionally use it on 20 and 15 meters and you're willing to accept the comopromise. I'll try to put some numbers this. I have whips for all three bands for comparison. 
> 
> When I operate mobile I use a 17-meter whip for this reason. A mobile whip with a larger tunable coil would work much better outside the design band, but my XYL (when she's riding in my CRV) prefers the svelte look of that skinny, single-band radiator :)
> 
> Wayne
> N6KR
> 
> 
> > 
> > 
> > wunder
> > K6WRU
> > Walter Underwood
> > CM87wj
> > http://observer.wunderwood.org/ (my blog)
> 
> 
> 
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