[TowerTalk] Using a Concrete Slab as Part of Vertical Counterpoise?

[Michael Tope]

Guess I should have known better than to post a practical
inquiry in the midst of the annual porcupine pissing contest :):)

73, Mike W4EF..........................

----- Original Message ----- 
From: "Michael Tope" <W4EF at dellroy.com>
To: "Roger D Johnson" <n1rj at adelphia.net>; <k1ttt at arrl.net>; "Jim Lux" 
<jimlux at earthlink.net>

>
>
> Here is a practical question you UFER guys. I am planning to
> have some front yard hardscaping done in the next month or
> so (concrete retaining wall, steps, pilasters, etc). My thought
> was that following excavation and prior to the pour for the
> new concrete, I would lay down a fairly dense radial field for
> my short 160 meter vertical. The radials would start at the base
> of the vertical and then fan out into the front yard:
>
> http://www.dellroy.com/W4EF's-Ham-Radio-Page/Radial_Project/Radial.htm
>
> Originally I was planning to have the existing driveway slab
> demo'd and replaced but due to cost constraints, I've decided
> to keep it as is. Unfortunately, if I keep the existing driveway slab
> as planned, the front yard radials for the 160 meter antenna will
> have to be cut short about 20 feet of reaching all the way across
> the front yard (see illustration above).
>
> The UFER discussion got me to thinking that perhaps I could
> somehow tie the ends of the front-yard radials into the edge of
> the existing driveway slab so that could get some additional RF
> grounding benefit as compared to letting the front-yard radials
> stop just short of the slab.
>
> So the question is, how would I go about attaching the ends
> of the radials wires to the edge of the slab in a way that would
> provide a low resistance/reactance connection to the slab? I
> have a bunch of 3/8 diameter "Red Hat" concrete anchors left
> over from another project, so one thought was to use these to
> provide the connection. The Red Hat's wouldn't provide much
> actual contact area, however, as the only place where there is
> significant contact force between the metal and the concrete
> would be under the head of the hex-nut/washer and the wedge
> on the end of the anchor.
>
> Anyway, I would be interested in suggestions on how best to make
> these connections (or if its even worth bothering with). BTW,
> I should mention that my main goal for the radial system is to
> lower the losses of the radial system in order to raise the
> antenna efficiency. I am on dry rocky soil here with a less than
> ideal radial field arrangment (antenna on side of house), so I am
> looking for every last drop of efficiency that I can squeeze out of
> the system. As far as lightning protection goes, I am in Southern
> California, so this isn't a big concern.
>
> Thanks,
>
> Mike W4EF............................................
>