Where to guy?

[Vic Rosenthal]

I am putting up a Cushcraft R8 antenna on a flat roof that is about 3m x
3m square. The antenna is sitting on a 1m mast; the antenna itself is
about 9m tall.

It will have four guy ropes to the corners of the roof. What is a good
height at which to attach them to the antenna?

Are there rules of thumb for this?
--
Vic, K2VCO/4X6GP
Rehovot, Israel
http://www.qsl.net/k2vco/
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[Mike Reublin]

Mine is ground mounted on a 10' mast. I used 2 sets of guys, 1 at the top of the mast, the other about 17' up the R8.

73, Mike NF4L

On Sep 6, 2014, at 6:18 AM, Vic, K2VCO <[hidden email]> wrote:

> I am putting up a Cushcraft R8 antenna on a flat roof that is about 3m x 3m square. The antenna is sitting on a 1m mast; the antenna itself is about 9m tall.
>
> It will have four guy ropes to the corners of the roof. What is a good height at which to attach them to the antenna?
>
> Are there rules of thumb for this?
> --
> Vic, K2VCO/4X6GP
> Rehovot, Israel
> http://www.qsl.net/k2vco/
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
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[John Tipka]

Vic,

My R8 is ground-mounted on 21 foot length of SS40 high yield strength
50,000 PSI steel pipe used for high security fencing. The pipe is buried
three feet deep in concrete. It is guyed at the 17 foot point of the
base pipe with 1/8" wire rope, and between the BC-BD joint of the R8
just below the worm clamp and above the insulator supporting the stub
tubes. The guys to the R8 are 1/8" black UV resistant parachute riser
cord. The R8 has been used for eight years without failure through
several severe storms with 50-60 mile per hour winds and a devastating
"derecho" June 29-30, 2012. My station is located eighteen miles east of
downtown Columbus, Ohio.

I suggest the BC-BD junction as the point for top guying.

John W8UL

On 9/6/2014 6:18 AM, Vic, K2VCO wrote:
> I am putting up a Cushcraft R8 antenna on a flat roof that is about 3m
> x 3m square. The antenna is sitting on a 1m mast; the antenna itself
> is about 9m tall.
>
> It will have four guy ropes to the corners of the roof. What is a good
> height at which to attach them to the antenna?
>
> Are there rules of thumb for this?

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[Bill-3]

Needs to be guyed in the middle (just below a joint) and the top (just
below the actual top). Use a hose clamp to hold a metal ring or two in
place - which will become your guying points. Use something like Kevlar
rope (1/8"from Radio Works), which is nonconducting and very strong.

I no longer have a full sized vertical, only an R5. However, the above
is what I used for years in the past and it was very effective - the
various verticals survived 75 MPH winds, ice. etc. (all the finest the
northeast can throw at you).

Now I use NVIS antennas for the K3 - just armchair quality rag chews.
Even that system is over built with 4-way guying of a 25 foot tubular
tower and #12 insulated wire (either copper-clad multi-strand or
Flex-Weave from The WireMan). If the winds damage it, I probably won't
have a house still standing.

Bill W2BLC - K-Line

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[Joe Subich, W4TV-4]

Be careful with your guying.  Even if the antenna is dead center, the
guy points will not be more than 2.1 m from the base.  With guy points
that close any tension in the guys will be converted almost entirely
into downward pressure on the antenna (buckling forces).

You will need multiple guys - at least the top of BB and top of BD and
perhaps the top of BT2 (30 meter trap).  Based on the "sleeve" at the
bottom of BC and double wall of BB, the BC/BB joint and BB section are
the most likely to buckle.  You want to keep initial tension in the
guys to a minimum to reduce the downward force as much as possible
with the short guy radius.

73,

    ... Joe, W4TV


On 2014-09-06 6:18 AM, Vic, K2VCO wrote:
> I am putting up a Cushcraft R8 antenna on a flat roof that is about 3m x
> 3m square. The antenna is sitting on a 1m mast; the antenna itself is
> about 9m tall.
>
> It will have four guy ropes to the corners of the roof. What is a good
> height at which to attach them to the antenna?
>
> Are there rules of thumb for this?
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