[TenTec] openwire feed OT

[Scott Harwood]

I run mine through the wall with two pieces of RG-8 coax WITHOUT the shield.  Spacing is same as balanced line and uses two separate holes.  
Scott K4VWK
---------- Original Message ----------------------------------
From: "NJ0IP" <Rick at DJ0IP.de>
Reply-To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
Date:  Thu, 2 Feb 2006 09:20:03 -0800

>Guys, this may be a stupid question, but if you use two parallel pieces of
>(long) coax, wouldn't you have twice the loss.  On the other hand, resistors
>in parallel would mean half the loss.  In any case, coax is lossy, heavy,
>and expensive, so why would you use a long run of two coax cables?
>
>Using short lengths to going through the wall is a good idea, but then why
>would you need to tie the shields together at all and why ground them?
>
>Sinisa?
>
>Cheers,
>Rick
>
>-----Original Message-----
>From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
>On Behalf Of Darwin, Keith
>Sent: Thursday, February 02, 2006 9:05 AM
>To: Discussion of Ten-Tec Equipment
>Subject: Re: [TenTec] openwire feed OT
>
>Ken (and others)
>
>Oh, man, true confession time here :-).  I've only done what I described
>one time, years ago.  I built a coax parallel feed line for a loop
>antenna.  The coax went from the back of the tuner, through the window
>and all the way to the antenna.  I connected the shields together at the
>tuner end of the line and tied it to tuner ground.  It worked fine.  I
>figured the same technique would be great for constructing a parallel
>balanced line for use inside and near things that would upset the field.
>Truth is I'm still not sure what to do with the shields :-)
>
>I believe that the 2 pieces of coax can go their separate ways as long
>as they start together and end together.  The shield isolates the center
>conductor preventing it from being affected by nearby stuff including
>the other half of the parallel feed line.
>
>I got the idea from an article in QST but don't really have the
>engineering or physics data to truly explain how it all works.
>
>In my personal case I feed RG-8x coax from the rig to the tuner which is
>mounted 50 feet away.  From the tuner I run RG-213 coax 30 feet to the
>base of my 28' vert antenna.  Doesn't work well on 80 but seems to work
>well on 40, 30, 20, 17 & 15.
>
>- Keith KD1E -
>
>-----Original Message-----
>From: tentec-bounces at contesting.com
>[mailto:tentec-bounces at contesting.com] On Behalf Of K. Indart
>Sent: Thursday, February 02, 2006 11:31 AM
>To: Discussion of Ten-Tec Equipment
>Subject: Re: [TenTec] openwire feed OT
>
>Keith,
>   I have two questions:  Do you keep the two coax pieces separated by
>the same spacing as your feed line,...or can you make ONE hole in the
>wall/window and feed both coax through one hole ?
>
>   Does it matter which end of the shields get tied together; inside the
>wall or outside the wall ?
>
>   Do you make the lengths of the coax JUST long enough to protrude
>outside and inside of the wall or how long ?
>
>Thanks, and it sounds like a very good idea.
>
>73, Ken  WA4RPH
>
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