[TenTec] openwire feed OT

[joel hallas]

If you use the coax as coax, all the fields are within the coax so 
relative spacing between them doesn't matter. I tied the shields 
together on both ends of the run so the signal will divide properly 
coming from either direction. I just grounded the shields inside the 
house as it hit the balun and lightning protection.

73, Joel

Scott Harwood wrote:

>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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>>    
>>
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