[RFI] Ladder Line and RFI/Noise

[Michael Coslo]

On Oct 19, 2010, at 3:48 PM, Jim Brown wrote:
> 
> There's at least one exception to this. A decade or so ago, N7WS did 
> some research, published in one of the ARRL Antenna Compendiums, showing 
> that WINDOW line gets pretty lossy when it gets wet. That is, of course, 
> dielectric loss. Likewise, water in coax is likely to greatly increase 
> dielectric loss.

Here's a link to the article:

http://users.triconet.org/wesandlinda/ladder_line.pdf

He put a wetting agent in the water they put on the ladder line. The ladder line I have worked with does not "wet" at all, which of course is why he used wetting agent. and putting wetting agent and water on the lines is an inaccurate experiment, showing only what would happen if rain had wetting agent in it.

His statement that ladder line would quickly lose it's water shedding ability is likewise flawed. I have ten year old ladder line that the water still beads right up on it. Polyethylene is not a substance that gives up that non-wetting quality easily.


- 73 de Mike N3LI -