[TowerTalk] R7 'radials'

[Jim Jarvis]

George,

Didier is right.  The R7, like others in the R3-R8 series from
Cushcraft, use some number of 39" 'radials', which are actually
a capacitative part of a decoupling network.  They are not radials,
per se, and they're made up of stainless steel whips, such as are used
for car radio antennas.  (I've had an R7, R7000, and R8...and still
have the R7000, as a portable antenna.)

The manual is available online from Cushcraft, by the way...and I believe
there are seven of these small whips.

Best of luck,

Jim/N2EA



-0-

There is no grounded part in an R7 type antenna. Mostly do not ground the
radials. If you want to ground something, that would be the shield of the
coax, at the attach point to the matching network.

If I recall, the matching network is composed of a balun and a step-up
transformer to convert the 50 ohm of the cable to the ~2000 ohm of a
vertical half wave radiator. The counterpoise only has to provide an
effective ground against the 2000 ohm impedance of the radiating element,
that's why Cushcraft can get away with such a small counterpoise compared to
a quarter wave vertical.

73,
Didier/KO4BB

----- Original Message -----
From: "George Yazzolino" <Kc7hkp at teleport.com>

> how does one attach radials to a cushcraft type antenna which has the 4
> little radials mounted on its mast. does one attach to the grounding bolt
on
> lower part of the mast or does one just lay out a ring of radials and go
to
> a ground rod under the antenna. i am not sure off to improve the cushcraft
> design.it is a R-7 model
>
> thanks very much there guys
>
> P. George Yazzolino
> 14801 NE 20 Circle
> Vancouver, WA.  98684
> KC7HKP...Grid CN-85
>