> From: km1h@juno.com (km1h @ juno.com)
> Subject: Re: TopBand: Slinky test results
To: <topband@contesting.com>
> Date: Wed, 20 Aug 97 17:16:30 +0000
>
> On Wed, 20 Aug 1997 07:58:52 +0000 w8jitom@postoffice.worldnet.att.net
> writes:
> >I should have posted the size I measured, it was about 2 - 3/4 inch
> >mean diameter.
>
>
> SNIP
>
> OK, then I now come up with a VP = .45 for the ones here.
NO.
For different s/d's (turn spacings divided by turn diameters):
s/d = 0.5 Zo 1280 ohms Vp= .42
s/d = 0.75 Zo 1060 ohms Vp= .55
s/d = 1.0 Zo 930 ohms Vp= .63
A Vp of .45 would require about one turn per 1-1/2 inches length. At
85 turns per slinky, one slinky would cover 127 inches or about ten
feet. If a 250 ft antenna used 25 slinkeys, Vp would be
approximately .45 .
A s/d of 1 would be 2.75 inches spacing. Or 85 x 2.75 for 234 inches
per slinky. 234 divided by twelve is 19 and a half feet. 250 feet
divided by 19-1/2 is about 13 slinkys.
If you have less than 13 slinkys per 250 ft, the Vp is higher than
.63 and the impedance lower than 930 ohms. The less slinkys, the
closer it comes to a conventional Beverage.
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