Fw: Re: Fw: Fw: Re: [Antennas] 450 Ohm Ladder Line

Sun, 15 Dec 2002 13:08:26

I'm a new follower of this list so if I'm not quite up to speed on this
thread, forgive me.

I doubt that removing much or even all of the dielectric will change the
attenuation by anything approaching 0.2 dB/100' (dry).

For example, I measured Wireman type 552, which uses 18 AWG stranded wire,
and a "homemade" line constructed with 18 AWG solid wire and no insulation.
 At 50 MHz the type 552 measured 0.38 dB/100' and the true open wire
measured 0.30, in exactly the same test setup.

In this case, there isn't 0.2 dB to be saved.  I agree, however, that with
the line wet, there is a serious difference.

Wes Stewart  N7WS

At 08:14 PM 12/14/2002 -0600, Sandy and Kees Talen wrote:
>That's right for HF, Harvey. The purpose of this exercise is to see what 
>can be done to minimize the effect on window ladder line in rain and 
>dew weather situations. I suspect the removal of web material will 
>only have a small (around 0.2dB per 100ft or less) influence when dry.
>Wet is a different story.
>
>73  Kees K5BCQ
>
>
>--------- Forwarded message ----------
>From: Harvey&Bessie <[email protected]>
>To: Sandy and Kees Talen <[email protected]>
>Cc: [email protected]
>Date: Sat, 14 Dec 2002 19:44:36 -0500
>Subject: Re: Fw: Fw: Re: [Antennas] 450 Ohm Ladder Line
>Message-ID: <[email protected]>
>References: <[email protected]>
>
>I would like to point out that the dielectric for purposes of impedance
>calculation and loss in this line and others like it, is mostly air. The
>webbing makes up only a small portion of the dielectric immersed in the
>field surrounding the conductors. Only when wet does the webbing cause
>any big problem.
>Harvey/W4TG
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