[TowerTalk] HyGain 155CA dampening rope

[Bob Shohet, KQ2M]

Hi David,

Two suggestions....

For the rope, I suggest braided polypropylene – it is easy to pull apart the braid and spread it out evenly over the element so that it fits under the element cap without “lumps”.  The polypropylene is also resistant to moisture.  You also might want to consider delicately taping over the element cap with Scott’s 33 or similar quality electrical tape.  This prevents moisture from getting into the element cap from any spaces between the rope and cap and the element.

I also do not use drainage holes in the element caps.  I don’t want moisture or spiders and /or other nesting critters getting into the element, which a drainage hole allows them to do.

Two additional suggestions....

I balance each of the Hygain antennas at the boom to mast clamp so that when held by the clamp the antenna will not dip.  It is MUCH easier to control in the wind this way and puts far less stress on the rotator because it does not have to deal with turning an unbalanced antenna.  I balanced the antenna by the following method:

I bought malleable rolled up lead sheeting and cut off pieces and put them at the end of the boom so that both sides of the antenna balanced at the boom to mast clamp.  I then drilled through the underside of the boom and the lead sheeting and screwed in a thick stainless steel eyebolt and bolted it to the bottom of the boom and inside the boom above the lead sheeting with 5/8” SS bolts so that it would not move.  Then after the eyebolt and sheeting is secured you waterproof the whole in the boom by using silicone bathtub sealant and let dry for a few hours.  Now you have a completely balanced Hygain antenna!  It takes another 1 – 2 hours to do this properly but you will never have to worry about fighting the wind with an unbalanced antenna!  I can’t tell you how much easier this technique makes it when you are dealing with long-boom antennas.

On the 15 and 20 meter Hygains, I also made a homebrew truss, mounted next to the boom to mast plate.  The truss consists of drilled 3/8” aluminum plate about 
9” x 12” which is drilled for 2 galvanized hoseclamps vertically and horizontally to which I insert a 3’ piece of steel 2” od mast.  On the top of the mast, I have two stainless steel eye-to-jaw turnbuckles that attach to the end of two galvanized muffler clamps.  From the turnbuckle I use phillystran rope that is cable clamped at three points on the near end and at the far end where it attached through another stainless steel eyebolt that attaches ~ 18” from the end of the boom through a hole drilled in the top and bottom of the boom and then waterproofed with silicone seal.

When the antenna is mounted on the tower or mast, I then turn the turnbuckles on each side and tighten them to leave just a tiny bit of sag.

The additional mast and truss adds about 15-20 lbs to the antenna and takes about 4 – 5 hours of time to make it and install it but it makes the antenna rock solid.  It is the only thing that has kept the booms from breaking in ice storms and violent winds.  I highly recommend this technique for any long boom antenna.  I don’t use it on my 10 meter Hygains but it would probably be helpful.  On the 15’s and 20’s it is essential at a heavy wind and/or ice prone location.

73 and GL!

Bob  KQ2M

From: David Aslin G3WGN 
Sent: Wednesday, June 21, 2017 11:06 AM
To: Bob Shohet, KQ2M 
Subject: RE: [TowerTalk] HyGain 155CA dampening rope

Thanks Bob! Good thinking IMO.  We’ve had some 90mph gusts here (only owned the property for a few months) so anticipating some wild Atlantic weather coming our way in the fall/winter.  Even though the antennas will be on telescoping towers, it’s still a PITA to fix a broken antenna, so I’ll be copying your method to the letter!  Had already ordered the all-stainless clamps.  Now just need to source new end caps and suitable rope, which should be straightforward.  

See you in the piles,

73, David G3WGN  M6O

 

From: Bob Shohet, KQ2M [mailto:kq2m at kq2m.com] 
Sent: 21 June 2017 15:49
To: David Aslin G3WGN <david at aslinvc.com>
Subject: Re: [TowerTalk] HyGain 155CA dampening rope

 

Hi David,

 

I have used the dampening rope in every single element of my 11 Hygain Yagis (105CA/155CA/205CA) at my extremely windy hilltop qth.  I have never lost an element or element tip and I believe that is from the combination of using the dampening rope held on by the element endcap plus the fact that I DOUBLE hoseclamp every telescoped element section. (I replaced all the Hygain element clamps with Stainless Steel hoseclamps).  I then generously taped over every hoseclamp with Scott’s 33 electrical tape.  What I did is a lot of extra time and energy and expense and it has been worth every penny since I have never had a single failure in 18 years since I put up my first tower and 105CA.

 

My qth and all antennas have survived two tornados (F0 and F1), the 110 mph gusts of Hurricane Sandy and 85 mph gusts of Hurricane Irene and countless violent Thunderstorms, Nor’easters and icestorms.  I am 100% certain that would not have been possible without the use of the dampening ropes/endcaps, replacing and DOUBLE hoseclamping (with stainless steel hoseclamps) each telescoped element piece and taping over the hoseclamps.

 

My thinking was that the cost of an extra $50 and two hours work per antenna on the ground for these items is nothing compared to the time, energy and hassle of losing a piece of or an entire element before or during a contest or when the wx precludes taking them down to fix them.

 

73

 

Bob KQ2M

 

From: David Aslin G3WGN 

Sent: Wednesday, June 21, 2017 10:22 AM

To: towertalk at contesting.com 

Subject: [TowerTalk] HyGain 155CA dampening rope

 

Mindful of Steve's 'Prime Directive' which suggests I absolutely should use the dampening rope in my recently acquired used 155CA, what is the experience of the TowerTalkian brains trust of the need for  the rope in a 155BA/CA at a relatively exposed site?
73, David G3WGN  M6O