[TowerTalk] Coaxial Inverted L

[wa3afs at inav.net]

A better description can be found on pages 72 and 73 of the August 1984 CQ magazine.  The only change that I 
have made was to use coax for the entire antenna instead of TV twin lead for the portion above the short.  (I found 
that it made no electrical difference, but was mechanically stronger).

The CQ article does reference pages 599-600 of the 1976 Radio Amateur's Handbook.

Other than more detailed construction information, I only have about 20 years experience with these antennas 
which I also scaled for other bands -- all with DX results that ran rings around my former dipoles and inverted Vs.

73s 
   Bruce

On 13 Jul 2006 at 18:09, K4SAV wrote:

> ..."Here we go again... so which is it? Inverted L's have plenty of 
> bandwidth or Inverted L's little bandwidth??? "...
> 
> The traditional L with a good ground doesn't have much bandwidth. But 
> WA3AFS doesn't have a traditional L. Unfortunately, from his description 
> I could not decipher exactly what his antenna looks like. It is possible 
> when using coax as an antenna element, and playing games with shorts at 
> the right places, to produce something with double resonances, which may 
> be what he has. NEC based tools can't analyze antennas such as this, so 
> experimental data may be all the data you can get.
> 
> A better description of this antenna might be useful to some of us.
> 
> Jerry, K4SAV
> 
> Robert Chudek - K0RC wrote:
> 
> >Gentlemen...
> >
> >Here we go again... so which is it? Inverted L's have plenty of bandwidth or Inverted L's little bandwidth???
> >
> >First, let me say if you are not taking your measurements AT THE FEEDPOINT, you are not seeing the true story. Second, a large bandwidth is not necessarily a good thing. The longer and more lossy your transmission line, the better your antenna is going to look from the shack.
> >
> >Here's an example of what I'm talking about... I have a low 160m inverted vee which I plotted VSWR graphs at the feedpoint and again at the end of 230 feet of rg8x coax. I made absolutely no antenna changes between these two measurements. I posted the superimposed VSWR and RETURN LOSS curves on my website, here: http://tinyurl.com/oh87y  The two PDF files are 72-KB each and can be downloaded and viewed using Adobe Acrobat Reader.
> >
> >In this specific example, measuring at the end of the coax leads you to believe you have 35% better bandwidth than in reality.
> >
> >73 de Bob - K0RC
> >
> >
> >
> >  
> >
> >>On 13 Jul 2006 13:20 WA3AFS wrote:
> >>
> >>Please be aware that the bandwidth for a coaxial inverted L is very 
> >>broad.  My SWR at 1.800 is 1.3 and slowly rises to 1.7 at 2.000Mhz.
> >>
> >>    
> >>
> >
> >But then on 13 Jul 2006 at 13:11, K4SAV wrote:
> >
> >  
> >
> >>>The biggest problem you have with low band multiple L antennas is 
> >>>matching and bandwidth. To start with, a 160 meter L will not have a lot 
> >>>of bandwidth...
> >>>      
> >>>
> >
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