This is Matt who asked the questions.
Thanks for all the responses. The tower has a 6"x6" plate on top.
One of the questions was grounding the feedline at the top of the tower and
then at the side of the house at the polyphaser a few feet from the tower.
Is this the typical practice? The Ward Silver book says this as I read.
Matt, AA3RO
On Sun, Nov 11, 2018 at 11:00 AM Bob Shohet, KQ2M <kq2m@kq2m.com> wrote:
> Between the ice and wind at some qth’s like mine, laying cable in loops on
> a top plate is just begging to have it catch on a corner or be frozen in
> place and tear. It is usually a bad idea for anyone to generalize from
> their qth to everyone else’s, just as it would be for me to generalize from
> my extreme wx qth to most other qth’s.
>
> As our climate changes, the resultant violent storms become ever more
> frequent and extreme. Even with 110 mph wind gusts – reachable now in most
> of the US - (the high end of an EF2 tornado or high end of a Cat 2
> hurricane) antennas and towers can survive and people might assume that
> everything else is ok and remained in place, like coax loops. You know
> those pictures of cars and small planes being flipped upside down even bad
> T-storms? What is the weight of a coax loop compared to that? All it
> takes is movement of a few inches to a foot and one end can easily slide
> off a corner and ges caught with very damaging results.
>
> For these reasons I have gone with hanging loops with ultimately better
> results at my qth. One advantage of a hanging loop is that you can rotate
> the antenna full scale with someone standing at the top of the tower (or
> under/above the sidemount) and observe what happens through a 360 degree
> rotation and make adjustments and then test it again. And you can, to some
> degree, simulate the effects of wind by pushing or pulling the loop in
> different directions to see what it does and move potential obstacles or
> “loop catchers” out of harms way. It is not foolproof but it is quite
> effective. I have not had anything catch since well before the past two
> Hurricanes, macroburst and two tornados at my qth, more than 10 years ago.
> Of course there is also luck involved. When Hurricane Irene and its 110
> mph wind gusts tore off the massive crown of a tall tree and hurled it into
> my tower 80’ away, it could have easily have caught on one of the antennas
> or coax loops or moved them, causing them to catch on something anyway.
> You can’t prevent everything, just take sensible and thorough precautions.
>
> I also like hanging loops because ice is far more likely to melt and fall
> away on a hanging loop when the sun comes out and assists gravity in doing
> the rest of the work. This is even more likely to occur if you spray or
> coat the cable with something that repels water, whereas with a horizontal
> coil of coax laying on a plate, when the ice melts it can simply refreeze
> in a blob and stay that way on the cable, freezing it in place. Many
> people don’t realize that even when the temperature is > 32 degrees F, if
> the ice is in the shade, it will take far longer to melt than when it is in
> the sun. So no guarantees that the fully ice will even melt when it could,
> especially if it is frozen into a blob with your cables frozen inside of it.
>
> Bottom line: Know your qth and the wx at your qth. And plan for the
> unlikely events that can REALLY cause problems for you, especially in
> Winter.
>
> 73
>
>
> Bob KQ2M
>
>
> From: john@kk9a.com
> Sent: Sunday, November 11, 2018 10:21 AM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Rotator loops was: Re: Feedline for a new tower
>
> That may work if the top plate is large enough. I am not sure what happens
> if the coax slips off the edge or how it would work with side mounted
> antennas (the majority of mine are side mounted) or with pointy top towers.
>
> John KK9A
>
> From: N4ZR
> Date: Sun, 11 Nov 2018 08:44:44 -0500
>
> I've never understood typical ham practice of a hanging loop. What Chuck
> describes is mechanically much superior.
>
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster
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--
Matt Frey CEM, LCP
Spry OSI, Inc.
P.O. Box 269
E. Petersburg, PA 17520
717 898 2300 office
610 659 5777 cell
matt@spryosi.com
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