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From: "James Moritz" <james.moritz@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
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Subject: LF: Re: Ladderline C per foot?
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Dear JB, LF Group,
The capacitance (per metre) of a transmission line is:
C = 1/(Zo.Vf.c)
Where Zo is characteristic impedance in ohms, Vf is the velocity factor,
which basically depends on the insulation, and c is the speed of light (3 x
10^8 m/s). For 450ohm ladder line, velocity factor seems to be around 0.9,
and the above formula works out to 8.23pF/m, or as Peter says, 2.5pF per
foot.
Cheers, Jim Moritz
73 de M0BMU
----- Original Message -----
From: "J. B. Weazle McCreath" <weazle@hurontel.on.ca>
To: "LowFER at LW Cafe" <lowfer@lwcafe.net>
Cc: <rsgb_lf_group@blacksheep.org>
Sent: Friday, February 02, 2007 10:33 PM
Subject: LF: Ladderline C per foot?
> Hello Lowfers & LFers,
>
> Does anyone on the lists happen to know the approximate
> capacity per foot of 450 ohm windowed poly ladderline?
>
> 73, J.B., VE3EAR - VE3WZL
> Solar and wind powered
> Lowfer " EAR" 188.830
> EN93dr
>
> http://www.hurontel.on.ca/~weazle
>
>
>
>