[TowerTalk] Guy rope damping

[markrob at mindspring.com]

Have you tried using a bungee cord between the hook and the rope. It should provide some damping.

Mark N1UK

-----Original Message-----
>From: "Roger (K8RI)" <K8RI-on-TowerTalk at tm.net>
>Sent: Apr 30, 2008 2:36 PM
>To: AI1P Matt Steven <KD0BVK at gmail.com>
>Cc: towertalk at contesting.com
>Subject: Re: [TowerTalk] Guy rope damping
>
>AI1P Matt Steven wrote:
>> Hello,
>>
>> I have a vertical antenna on a rooftop tripod that is guyed with 
>> stranded nylon rope.  The rope naturally gets vibrating very heavily in 
>> wind probably due to its uneven surface and it really can sing.
>>   
>I find that strange as I'm doing the same thing with no noise.
>What size rop and how much tension are you using.  Nylon is naturally 
>stretchy, but highly susceptible to weather and UV light.  After a 
>couple of weeks it should get quite stiff with little stretch left.  I 
>can't imagine the stuff being tight enough to sing/resonate.
>
>I have been using 3/16" to guy an AV-640 which makes me ask, what is the 
>vertical? Is it a trap vertical, Aluminum tube, steel pipe, or tower 
>sections?
>
>BTW, I'm replacing the guy line with some 3/16" braided poly rope which 
>has nearly twice the strength without the stretch or UV sensitivity.  
>The RFConnection has the 3/16" for less than 10 cents a foot and 5/16" 
>(1000# test) for 15 cents a foot. The 1/4" at 800# test is not as handy 
>with a core and separate jacket.
>
>73
>
>Roger (K8RI)
>> The problem is that the house hook it ties to is anchored (necessarily) 
>> to a roof joist for support and these vibrations transfer right into my 
>> bedroom making for plenty of banshees on windy nights.
>>
>> What I've tried so far to dampen it:
>>
>> 1) Wrap the anchoring hook very thickly with electrical tape.  little/no 
>> effect
>>
>> 2) Use scrap coax to absorb some of the vibration on the string as it 
>> comes in, before it touches the metal of the hook (acts as padding 
>> basically) little effect, the coax redirects some of the vibration but 
>> not enough to notice.
>>
>> 3) Same as 2 but running the actual tie-off to further down the roof, 
>> and just having the hook as a guide point.  Not much effect.
>>
>> I can't afford Phillystran or anything really nice like that, so that's 
>> out of the question, but is there any way to stay on the cheap and at 
>> least get the vibration to stop resonating in the rafters?
>>
>> 73s,
>> Matt
>> ai1p
>> _______________________________________________
>>
>>
>>
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>>   
>
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