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Re: Topband: Cutting Delay Lines

To: "'Ed Stallman'" <ed.n5dg@gmail.com>, "'Topband'" <topband@contesting.com>
Subject: Re: Topband: Cutting Delay Lines
From: "John Kaufmann" <jkaufmann@alum.mit.edu>
Reply-to: jkaufmann@alum.mit.edu
Date: Wed, 13 Jul 2016 09:48:21 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
In principle, any *odd* multiple of 4.118 MHz (the frequency where the cable
is 1/4 wavelengths long) will work when the far end of the cable is
open-circuited.  If you short-circuit the far end of the cable, then look
for X=0 at *even* multiples of 4.118 MHz.

73, John W1FV

-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Ed
Stallman
Sent: Tuesday, July 12, 2016 11:05 PM
To: Topband
Subject: Topband: Cutting Delay Lines

I'm cutting a 40 degree and a 20 Degree Delay line using RG6 at 1.83MHz for
a  receive 8 circle array ! I know the velocity factor of the RG6 and have
all the math worked out .

After doing the calculations and trimming the RG6 back , I'm looking for
X=0 at 4.118 MHZ ( or as close to X=0 as possible )

Now to my question: I'm finding the X=0 to be a broad range , looks to be +
- 50 KHz on my MFJ 259b .. I know , I need a better analyzer ... 
Can I double of quadruple the frequency to narrow the span where X=0?

Thanks Ed N5DG



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