[TowerTalk] Radial field question Single radial wires vs

[Grant Saviers]

Marine grade aluminum, 5000 series is used for ships and would be a much 
better choice when on/in/near earth.  More commonly available is 3003, 
also fairly corrosion resistant.  Neither approach the strength of the 
most common 6061 which is not a good choice for corrosion resistance.  
Tread or diamond plate is sometimes available at scrap yards and is 
often 3003.

I'm machining parts from 2.5" thick 6061 plate, so Jim now you know a 
thick plate buyer.

Grant KZ1W

On 10/28/2016 7:56 AM, Jim Thomson wrote:
> Date: Thu, 27 Oct 2016 23:28:50 -0700
> From: Jim Brown <jim at audiosystemsgroup.com>
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Radial field question Single radial wires vs
> mesh and more
>
> On Thu,10/27/2016 10:10 AM, Kevin Kidd wrote:
>> If it's not copper or some alloy thereof, don't waste your time for a
>> permanent installation.
> Some pretty sharp engineers disagree with this advice. Rob Sherwood,
> NC0B, first published on the usefulness of galvanized ground screen in
> 1977, and talked about it in presentations in the Dayton Antenna Forum
> in 2008 and 2009. Rob  is best known for his work on quantifying the
> receive performance of modern HF rigs. Like anything making contact with
> the chemical makeup of soil and local moisture at any given QTH,
> materials that work in one location may not work in another.
>
> 73, Jim K9YC
>
> ## around town here, galvanized anything  will  disintegrate in the ground.
> Ditto with my old qth  400 miles north of me.   One fellow here in town, who was
> renting a home, placed the bottom of his tower into the hole, then filled it back up with dirt.
> Guyed tower, so no worry about the base kicking out or anything.  After 10 yrs, the tower
> was taken down.   There was almost nothing left in the ground, it had eaten itself.
>
> ##  Having said that, the telco I worked for, used  6 ft  galvanized grnd rods. Any electrical
> outfit will always use 8 ft  copper clad rods, jack hammered into the ground.  I used  8 ft copper
> rods, then cadwelded them to 2 gauge bare cu...aprx 2-4 inches below the ground.
>
> ##  I believe it depends whether the dirt /clay is alkaline..or acitic.
>
> ##  What else that works is a 3-4 ft diameter /square piece of AL plate, like .25 inch thick  6061-T6
> etc.   Vert goes in the middle.   Then short and long radials from the circumference of the plate.  By adding the
> shorter radials inbetween the longer ones, you can achieve the effect of a screen at the base of the vert.
> I did this on a 40m roof mounted vertical years ago, and drilled and tapped the al plate. ( plate was only
> 12 inches square)  The 60 x 15-30 foot long radials laid directly on the roof.   That was the best 40m vertical
> I have used to date.  The vert itself had to be lengthened  quite a bit to resonate the vert, since none of the radials
> were resonant.  Vert was guyed  with dacron rope.
>
> ##  Local al  supplier has  4 x 8 foot sheets of al plate in any thickness.... like up to 2 inches thick..
> ( still dont know who buys al plate that thick).
>
> Jim   VE7RF
>
>
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