Topband: Beverages 2 basic questions

[ZR]

----- Original Message ----- 
From: "Tom W8JI" <w8ji at w8ji.com>
To: "topband" <topband at contesting.com>
Sent: Sunday, December 02, 2012 12:46 PM
Subject: Re: Topband: Beverages 2 basic questions


>> resistors. Id guesstimate the general F/B to be over 20dB on 160. My 
>> feeling is that performance could not be duplicated by various other 
>> loading methods. If somebody wants to make real world comparisons it 
>> might be beneficial.
>
> I looked at slinkys when I lived in Conyers. None of this is magical or 
> difficult, nor are antenna slinkys or helical loads "special".

** After I brought Slinkys up on the forums and on 160 in the late 80's and 
90's. Your comments then were just what I expected.

The behavior
> is the same as a series of lumped inductors spaced fractional wavelengths 
> along the antenna.

** Maybe on paper which is why Ive asked others to make the real world 
comparisons. I find it hard to believe that a wire being randomly 
interrupted by a lossy lumped inductance plus capacitance can privide 
identical results.

> There is a certain optimum phase shift along an antenna's length. There 
> are many ways to accomplish that, and if the resulting current 
> distribution and phase is the same the results will also be exactly the 
> same.

** Nothing beats a helice for a loading device for a steadily progressing 
phase shift. No guesswork needed. It even worked for high gain UHF 
transmitting antennas.


Sometimes, like
> with long antennas fired away from the feedpoint, we don't want that 
> delay. We actually might need a phase advance.

** Thats not related to the subject under discussion.

>
> The only thing magical about slinkys is how they can go down steps without 
> feet, and without holding on to the banister! I never have figured that 
> out.

** No magic involved in how they work as an antenna or as a toy, the toy 
part has been thoroughly explained ages ago.

Carl
KM1H