[TowerTalk] Question on Multiple Inverted L Antennas

[Robert Chudek - K0RC]

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...