[TowerTalk] Rotor Loop Question

Wed Nov 16 10:02:31 EST 2016

I think I got the idea from here on TT or somewhere.  The mock-up was
dimensionally accurate and used to cut the loop cables and make the bundle
on the ground.  If you notice, there's a coax grounding bracket on the
mast.  The loop cables go from the mast bracket down to a grounding bracket
near the top of the tower.  The goal was to have replaceable jumpers in
case of abrasion or rotor limit switch failure.

I'll email you the jpg file.

73, Glenn - KD0Q

On Tue, Nov 15, 2016 at 9:08 PM, Gedas <w8bya at mchsi.com> wrote:

> Hi Glenn, wow that's a great model you built up to test your setup. I
> think that's really cool. I was going to cut the corners of my top plate
> off to eliminate any sharp corners etc but seeing what you did here I may
> just attach a larger plate on top of the existing plate to give the turns
> of coax something to sit on and to hold it up. Mt top plate is only about
> 6"-7" on each side (Universal Aluminum tower). That's a really neat idea, I
> was trying to make one large drooping loop work but your idea uses several
> tight turns. I may even have enough length in the coax I currently have
> cut. All I would have to do is wind them up around the mast much tighter.
> Could you send me directly a close up of the actual installation? The URL
> allowed me to zoom once but there was not enough magnification and
> resolution to clearly see how it finally turned out. Thanks for sharing
> this.
>
> Gedas, W8BYA
>
> ----- Original Message -----
>
> From: "KD0Q" <kd0q at traer.net>
> To: "Gedas" <w8bya at mchsi.com>, towertalk at contesting.com
> Sent: Tuesday, November 15, 2016 9:40:51 PM
> Subject: Re: [TowerTalk] Rotor Loop Question
>
> Hi Gedas,
>
> What I did was coil the bundle around the mast 3 times so the bundle winds
> and unwinds, less lateral flex that way. A 45 deg PVC elbow protects the
> bundle from the top plate.
>
> Here's a pic of the mock-up I did -
> http://s171.photobucket.com/user/gathorne/media/Rotor%
> 20Loop/DSCF0528.jpg.html
>
> Here's the actual tower install -
> http://s171.photobucket.com/user/gathorne/media/Tower/DSCF0536.jpg.html.
> Zoom in and you can see the white 45 deg elbow.
>
> 73, Glenn - KD0Q
>
>
> On Tue, Nov 15, 2016 at 7:25 PM, Wayne Kline <w3ea at hotmail.com> wrote:
>
> > Hi Gedas
> >
> >
> > I have in the past with multi antennas on one mast, I grouped the
> > coaxes together ( the most I had was three coaxes
> >
> > RG 213 ) I taped them in a loop and inserted the coax in a 1" id HD
> > tubing/hose . This prevented the edges from chaffing the coax
> >
> > in the rotation .
> >
> > As for hardline to coax I run them just below the rotor shelf
> > and then group the coax up one leg into the hose cover .
> >
> >
> > Wayne W3EA
> >
> >
> > ________________________________
> > From: TowerTalk <towertalk-bounces at contesting.com> on behalf of Gedas <
> > w8bya at mchsi.com>
> > Sent: Tuesday, November 15, 2016 6:58 PM
> > To: towertalk at contesting.com
> > Subject: [TowerTalk] Rotor Loop Question
> >
> > I am hoping to get a better idea on how to implement my rotor loop for
> one
> > of my towers. The tower is a 70' aluminum universal that I use for my
> VHF &
> > UHF antenna in addition to a short rotateable dipole for 40m. The stack
> > consists of: a 17B2 at ~85', a 23 elem 70 cm yagi at ~81', a 5 elem 6m
> yagi
> > at ~76', and the 40m dipole at ~71'. I am using new Davis BuryFlex (a low
> > loss RG-8 type coax) for all my loops. I have 3 runs of 7/8" heliax going
> > up the tower for 6m, 2m, and 70 cm, and use the BuryFlex for the 40m
> > dipole. All 3 heliax ends currently stop about 1' below the very top of
> the
> > tower plate. That top plate BTW is a square aluminum plate with sharp
> > edges. I plan to use a sawzall to cut the corners off and file them
> smooth
> > to help lessen the chances of damage to the coax loops if they touch that
> > plate while rotating the mast.
> >
> > Today I made my initial connections of the BuryFlex cables to the
> antennas
> > and roughly taped all of them in place along the booms and down the
> mast. I
> > have all 4 rotor loops tightly bundled together and held in place with
> > electrical tape every foot or so. I formed the rotor loop with a length
> of
> > about 5' and have it secured to the mast several inches below the 40m
> > dipole then to the top of the tower about 6" down off the top.
> >
> > Here is the issue.....that bundle of 4 coaxial cables seems to be so
> stiff
> > & easy to get twisted up into a mess it just does not seem like it will
> > work well when I raise the tower back up. The tower is currently tilted
> > over via a home-brew mechanism I designed & built and can work on the
> loop
> > in comfort so I can try different ideas. I am wondering:
> >
> > 1. What is the best length for the loop(s) to be? And what shape should
> > the loop be? I define the loop to be the lowest place on the mast where
> the
> > cables are taped to the first place the bundle is taped to the tower top.
> >
> > 2. Should I separate the bundle of cables so it is not a single stiff
> > "clump" of cables ? I.e., maybe just let all the coax loops droop freely
> > and not be bound to each other?
> >
> > 3. I am able to change where the ends of the heliax ends up near the
> tower
> > top....how far off the top should the heliax end to make the best rotor
> > loops?
> >
> > Appreciate any thoughts and ideas you may have.
> >
> > Gedas, W8BYA
> >
> >
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> >
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