The Rohn specs allow for two sets of guys on 100 feet of Rohn 45 in its lowest
wind-zone rating. Upper guys (at 85 feet) are 1/4" EHS and lower are 3/16" EHS.
In higher wind zones three sets of guys are specified.
I've had such a tower with two sets of guys here in central Delaware for the
past 21 years, with a 3-stack of HyGain 204BA yagis on it. The guys are
insulated EHS steel. I've never found any problem with the lower beams
interacting with the guys.
I have successfully shunt fed several Rohn 25 towers with insulated EHS steel
guys. Some have had a 6-foot section of EHS connected to the tower before the
first insulator, others used a bent pin shackle to place the first insulator
right at the tower. I haven't noticed any difference with either method.
Nonresonant insulated guy lengths used typically are 58 feet or 39 feet, taken
from a chart in the ARRL Antenna Book.
At this QTH I have a 119-foot series-fed Rohn 25 for 160m, which started with a
combination of Phillystran and insulated EHS guys. When trees grew and risked
chafing of the Phillystran guys, I replaced those with insulated EHS steel, and
I didn't see any change in tuning or performance.
Phillystran is a great material if the tower is in the clear and there's no
risk of chafing from tree branches. Do use a length of steel at the bottom 10
feet or so of each guy, for ease of adjustment, fire safety and vandalism
prevention. DX Engineering sells a nice kit for those tails.
If in doubt on any phase of your plans, consider hiring a structural engineer
to review them. You may need this anyway to obtain your local building permit.
Jon P. Zaimes, AA1K
Tower climber for hire
Reviews of AA1K tower work on eham website:
Hug your favorite tower every day, and always stay connected to it.
From: TowerTalk <email@example.com> On Behalf Of Jeff Blaine
Sent: Monday, December 16, 2019 7:14 PM
Subject: Re: [TowerTalk] 45G and guys
On the question of "Will the EHS cause interactions" - the answer is YES.
That is true regardless of length, although the magnitude of the interaction is
going to be a factor of many things including the length and proximity. It's
possible to pick lengths that minimize the impact depending on band, etc.
So if you plan to mount a beam among the guys, definitely use insulated guys
like the Phili stuff as that takes interaction problems off the table for the
On 12/16/19 1:27 PM, firstname.lastname@example.org wrote:
> You should do your homework before trusting any installer, this
> information is readily available. Rohn's catalog will clearly answer
> your question regarding guy locations and the EHS type. This varies by
> wind speed and wind load. If you are going to have side mounted
> antennas I would definitely use all non-metallic guys. See the
> Phillystran catalog for the equivalent kevlar cables and proper
> installation techniques.
> John KK9A
> Ignacy Misztal no9e wrote
> I want to have a 100ft 45G installed on my new property. It will hold
> JK Mid Tri 40 on top. I plan on adding a Yagi with a swinging gate at
> lower level later, and perhaps shunt loading for 160 and 80m.
> My installer wants to use 3 sets of EHS wires. He is ready to
> substitute the top one with Phillistran. So here are my questions:
> Are EHS guys likely to cause interactions with top and medium beams?
> Do EHS guys compromise tower for 160M shunt feeding?
> Do I need 3 sets of guys?
> Should I move to Phillistran?
> Is Phillistran 7000 lb on top and 4000 at bottom good enough?
> The installer wants to build the tower with the beam on top. Have the
> beam at 3 ft, then raise to 13, 23,....Perhaps that's why 3 sets of
> guys. The location is in E GA, with relatively low wind.
> Ignacy, NO9E
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