[TowerTalk] ROTOR LOOPS, DAVIS RF
Steve Davis | Davis RF
sdavis at davisrf.com
Fri Nov 20 13:19:55 EST 2020
HI T-talkers,
I do not suggest the wrap around the mast method. RG 213 and other similars have small single bend radiuses, close to the OD of most masts. Repeated bend radius's also raise issues.
The typical hanging loop : Been in use for decades and if done correctly is fine. Correctly: you want to well secure the coax to a near top member on the tower, and same on the mast near the ant feed point. But be sure when you secure the coax, you aren't affecting the concentricity of the coax. For instance, clamping the coax with radiator clamps is a no-no.
The least expensive and effective way is to wrap UV resistant tape around the coax and onto the tower member or boom. I suggest a length of tape about 4-5 ".
We also have SS or galv. strain reliefs which have a dead wire that comes off them to attach to the tower or boom member. You can pull up on the wire so that the kellum is against the tower (or boom ) member to avoid swinging in the breeze.
Cheers, Steve K1PEK Founder, DAVIS RF Co. and also DAVIS Rope and Cable Assembly Co. LLC (Cable assembly is metallic cable only, Davis RF does coax, hard line, etc coax cable assemblies to mil std's. Heliax, RFS, LMR: FREE shipping, & lowest prices of any ham dealer)
Note: Steve, K7LXC has ok'd a bit of such product notifications.
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Subject: TowerTalk Digest, Vol 215, Issue 23
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Today's Topics:
1. Rotator loop - another question (N4ZR)
2. Re: Rotator loop - another question (Ken K6MR)
3. Re: Rotator loop - another question (Robert Harmon)
----------------------------------------------------------------------
Message: 1
Date: Fri, 20 Nov 2020 08:42:22 -0500
From: N4ZR <n4zr at comcast.net>
To: TowerTalk <TowerTalk at contesting.com>
Subject: [TowerTalk] Rotator loop - another question
Message-ID: <4ae44c4b-2fc3-4a9a-1205-a5083cff54bf at comcast.net>
Content-Type: text/plain; charset=utf-8; format=flowed
In my old station, someone came up with this idea - instead of an actual
loop, start with the rotator at mid travel and wrap at least two *loose*
turns of RG-213 around the mast, then connect to the balun or
feedpoint.? It worked fine with no problems in 20 years.
It seems to me that doing it this way provides physical support for the
loop, which could be beneficial in high winds, but when I was putting up
my current yagi, people working with me poo-pooed the idea, and so I
wound up with the conventional loop.? It hasn't failed yet, but...
So, what's the informed opinion?
--
73, Pete N4ZR
Check out the Reverse Beacon Network
at <http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.
------------------------------
Message: 2
Date: Fri, 20 Nov 2020 16:35:11 +0000
From: Ken K6MR <k6mr at outlook.com>
To: N4ZR <n4zr at comcast.net>, TowerTalk <TowerTalk at contesting.com>
Subject: Re: [TowerTalk] Rotator loop - another question
Message-ID:
<BYAPR07MB62148AB57C9E23F6C86E93E09EFF0 at BYAPR07MB6214.namprd07.prod.outlook.com>
Content-Type: text/plain; charset="Windows-1252"
I use three loops, and have the rotator set at the loops ?tightest? point (depends on which way you wrap the loops) when installing. The loops change size very little when rotating so no risk of snagging anything. And they are self supporting.
Ken K6MR
From: N4ZR<mailto:n4zr at comcast.net>
Sent: Friday, November 20, 2020 05:51
To: TowerTalk<mailto:TowerTalk at contesting.com>
Subject: [TowerTalk] Rotator loop - another question
In my old station, someone came up with this idea - instead of an actual
loop, start with the rotator at mid travel and wrap at least two *loose*
turns of RG-213 around the mast, then connect to the balun or
feedpoint. It worked fine with no problems in 20 years.
It seems to me that doing it this way provides physical support for the
loop, which could be beneficial in high winds, but when I was putting up
my current yagi, people working with me poo-pooed the idea, and so I
wound up with the conventional loop. It hasn't failed yet, but...
So, what's the informed opinion?
--
73, Pete N4ZR
Check out the Reverse Beacon Network
at <http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.
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Message: 3
Date: Fri, 20 Nov 2020 08:50:00 -0800
From: Robert Harmon <k6uj at pacbell.net>
To: TowerTalk <TowerTalk at contesting.com>
Subject: Re: [TowerTalk] Rotator loop - another question
Message-ID: <68CC55DE-9946-4B25-B5A1-77558BC1649E at pacbell.net>
Content-Type: text/plain; charset=utf-8
Ken & Pete,
Thanks for sharing the rotator loop info.
I am changing the coax on my tower and have been trying to think of a better way to do the loop. I like this idea and will try it myself.
Now I need to decide whether to start with the rotator at mid travel or all the way around. Probably doesn't make much difference,
the yagi is 8 feet above the rotator..................
73,
Bob
K6UJ
> On Nov 20, 2020, at 8:35 AM, Ken K6MR <k6mr at outlook.com> wrote:
>
> I use three loops, and have the rotator set at the loops ?tightest? point (depends on which way you wrap the loops) when installing. The loops change size very little when rotating so no risk of snagging anything. And they are self supporting.
>
> Ken K6MR
>
> From: N4ZR<mailto:n4zr at comcast.net>
> Sent: Friday, November 20, 2020 05:51
> To: TowerTalk<mailto:TowerTalk at contesting.com>
> Subject: [TowerTalk] Rotator loop - another question
>
> In my old station, someone came up with this idea - instead of an actual
> loop, start with the rotator at mid travel and wrap at least two *loose*
> turns of RG-213 around the mast, then connect to the balun or
> feedpoint. It worked fine with no problems in 20 years.
>
> It seems to me that doing it this way provides physical support for the
> loop, which could be beneficial in high winds, but when I was putting up
> my current yagi, people working with me poo-pooed the idea, and so I
> wound up with the conventional loop. It hasn't failed yet, but...
>
> So, what's the informed opinion?
>
> --
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
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