Topband
[Top] [All Lists]

Re: Topband: radial wire source

To: <topband@contesting.com>
Subject: Re: Topband: radial wire source
From: "Tom W8JI" <w8ji@w8ji.com>
Reply-to: Tom W8JI <w8ji@w8ji.com>
Date: Tue, 5 Jun 2012 13:23:56 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
> You really do not need stranded wire. Bare solid wire is typically used
> for grounds.

Solid wire lasts longer, and is easier to connect to later because it is 
easier to remove all corrosion without chemical cleaning or strand-by-strand 
cleaning.

Also beware of gutting old wires, because some (like twinlead) are copper 
clad steel with thin copper. After a while, it will rust apart.

Nothing lasts like solid copper. I use #16 tinned copper buss wire, bought 
on 5000 foot reels. Stuff installed in 1998 looks like new when I dig it up, 
and lightning never has melted it.

 and while the standard of 120 radials spaced 3 degress is a
> well known standard for ground systems, it is very rare in amateur
> radio. >>

The only reason 120 radials were ever used is because the FCC excludes some 
complex verification measurements when a standardized system they chose is 
used. It has nothing to do with how it works. Often, 30-50 radials is 
immeasurably different than 120.

> Having installed many MW systems, I can tell you the ideal is not always
> achieved. At the end of the day, get as much wire in the ground wherever
> it is possible.

That is always the best advice, because even similar systems and locations 
can be different. Also, measured base resistance does not translate into 
efficiency. I've had 1/4 wave verticals with ground systems making 50-60 ohm 
base resistance equal in performance to the same antenna, at the exact same 
spot, with radial systems making 35 ohm base impedances. This is because 
radials have standing waves, even buried radials, and transform impedance.

73 Tom 

_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK

<Prev in Thread] Current Thread [Next in Thread>