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Re: Heliax cable bend?
To: CRTech <crtech@crtech.org>
Subject: Re: Heliax cable bend?
From: Kevin Kidd <kkbroadcastengineering@gmail.com>
Date: Sun, 18 Nov 2018 16:34:59 -0600
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In-reply-to: <004501d47d17$00d86b10$02894130$@pilgrimradio.com>
References: <004501d47d17$00d86b10$02894130$@pilgrimradio.com>

Be very careful straightening out that sharp of a bend.  IF it is older line, it can probably be carefully straightened out without problem.  IF it is new foil thin copper line, maybe not so much.  Just be careful and support the bend on the back side.  The line probably won't break or fail catastrophically in the straightening process but might retain some egg shape or creases that would reduce the voltage handling of the area. The center conductor will probably remain reasonably centered in the jacket.   Key word here PROBABLY...

However, check to see if the line has been kinked over immediately behind the connector.  IF it has, it will need to be cut off and the connector reinstalled.  I have repaired a number of AM and FM installations where the cable was bent sharply behind the connector and suffered a burn out at the kink.  In this case, the center conductor will take the shortest route thru the kink and ends up much closer to the center of the kink than it should be.

Kevin C. Kidd, CSRE/AMD
Lawrenceburg, TN
AM Ground Systems Company  -  WD4RAT
kkidd@kkbc.com  --  866-22-RADIO -- 866-227-2346

On Thu, Nov 15, 2018 at 2:11 PM Bill Hurne <billhurne@pilgrimradio.com> wrote:

Re-working RF plumbing at an installation, want to straighten a 90 degree bend near end of in 3 inch 50 ohm corrugated Heliax.    I think it is HJ8-50B, but not sure.  Existing Cable bend has about a 20 inch radius, recommended radius is no less than 30 inches.   It is working fine with the 20 inch radius and is pressurized.


Would I be safe to straighten the bend?   Would straightening cause damage requiring cutting off the bend and adding cable?   Of course work needs to be done while off air, just want to know how long we will be off, etc.


Bill Hurne
Chief Engineer
Pilgrim Radio


P: 775-883-5647  Ext 18

6363 U.S. Hwy. 50 East
Carson City, NV  89701







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References: Heliax cable bend?
("Bill Hurne" <billhurne@pilgrimradio.com>, 15 Nov 2018 19:11:38 -0000)
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