[TowerTalk] The TH7 and Damping Rope

[K9MA]

My TH7 is not as old, 1989 vintage. I haven't tried to get the element 
segments apart since I took it down this spring. I never had any trouble 
with it, but about 5 years ago I discovered that the boom guy cable, 
clamps, and boom to mast bolts were rusting. I had to take the boom off 
the mast, but I was able to reach the clamps without taking the antenna 
down. Replacing two of the mast clamp bolts would have required 
disassembling the transmission line, which I didn't want to do on top of 
the tower. It's sitting on sawhorses now, with those rusty bolts still 
trapped in there. Should have checked all the hardware with a magnet!

73,
Scott K9MA


On 7/20/2019 21:27, Don wrote:
> Interesting. Got my TH7DX in late '82, maybe early '83. Instructions 
> required the damping rope ONLY in the untrapped elements. I missed 
> this part when I assembled mine, finally discarded the rope. The 
> antenna has been up, down, disassembled, up, down, moved, reassembled 
> and I've never used dampening rope. Do use the end caps except for 2 
> that were lost a few years back. Always windy here on the coast and 
> big sustained winds in the winter but have never had an element 
> failure. The sole issue I've had (besides the really crappy BN-86 
> balun which was replaced early on) was the use of the cheap plated 
> screws inside the traps at the coil ends which became a rust ball. I 
> did replacement with SS and the appropriate conductive grease on the 
> DE 15M traps (my problem last summer). I need to do the other traps 
> this summer.
>
> _I am still looking for advice on how to put the antenna element 
> tubing pieces apart._ I used the grey/silver tubing coating that was 
> originally supplied with the antenna back when and the tubing to 
> tubing points are frozen, solid. Have tried a few things but not heat. 
> Was hoping to pull everything apart last summer for a good overhaul, 
> but ran into the freeze problem and ran out of time. Fixing the traps 
> was easy. So someone must have a good suggestion for getting frozen 
> element tubing apart so it can be cleaned and reassembled.
>
> Don W7WLL
>
> Don W7WLL
>
> On 7/20/2019 6:47 PM, K9MA wrote:
>> My TH7, assembled according to the manual with ropes and end caps, 
>> was up for almost 30 years, with no failures. I do wish I had noticed 
>> before I put it up that a few of the parts weren't stainless.
>>
>> 73,
>> Scott K9MA
>>
>> On 7/20/2019 20:35, Richard Smith wrote:
>>> I believe that the rope in the elements, specifically the element 
>>> tips, is particular to the Hy-Gain yagis, at least the 20, 15, and 
>>> 10 meter designs. I have seen a Hy-Gain yagi, a 5 element 15 meter 
>>> yagi, with most of its element tips broken off by regularly 
>>> occurring, but not huge, winds. The yagi was built without the rope 
>>> in the element tips that is shown in the manual for the antenna.
>>> I replaced the element tips in 1992, with the rope in the tips per 
>>> the instructions in the manual, and did not have any element tips 
>>> break off during the next 17 years of service at the same location.
>>> Just sharing my experience.
>>> 73, Rich, N6KT
>>
>>
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-- 
Scott  K9MA

k9ma at sdellington.us