Mark Keith wrote in message ...
Brian Kelly wrote:

Mark Keith wrote in message ...
Brian Kelly wrote:


Center-fed dipole-based antennas don't need station or installation
site RF grounds. Horizontally or vertically oriented. All end (base)
fed verticals need RF gounds so don't use 'em in your situation.

I've never needed an rf ground for a base fed half wave. A decoupling
section with radials is an option to reduce feedline radiation..Not
required to work though. MK

You lost me Mark. You have a vertical half-wave wire fed at it's base.
You have an unbalanced L/C network which matches the very high
feedpoint impedance to, say, a random length of 50 ohm coax. What do
you do with the coax braid and the ground side of the tuner?

Brian w3rv

Using the usual "gamma loop" feed I generally prefer for those, the coax
shield is connected to the "ground" side of the single turn coil. "appx
9-11 inches dia. for a 10m version" I usually make these from 3/8
tubing... That point is at ground potential as far as the mast, base
support, etc..The other side of that coil is connected to the base of
the radiator. The center conductor taps the single turn coil at the
point for best match. A capacitor from ground to coil "hot" side is
optional. In general you use about 50 pf for a 10m version. Double for
20m, double again for 40m, etc... I use a piece of coax for those. "open
end, don't short" For 10m, it's only about a foot or so long...Look at a
cushcraft 10m ringo. "model AR-10". They have PDF manuals on the web
with pix..That is the same basic design I use. They also make 2m
versions...BTW, I make these from tubing, and are self supporting.
Rarely use wire...These antennas work quite well. Good 10m antenna...The
higher, the better..Add decoupling, even better, but not required to
work..MK

OK, I see what you're up to. Over the years I've had a plain Ringo and
two Ranger versions for 2m and yes they work well. They do tend to
induce a lot of RF in the feedline though.

Tnx,

w3rv

Mark Keith wrote in message ...
Brian Kelly wrote:

Mark Keith wrote in message ...
Brian Kelly wrote:


Center-fed dipole-based antennas don't need station or installation
site RF grounds. Horizontally or vertically oriented. All end (base)
fed verticals need RF gounds so don't use 'em in your situation.

I've never needed an rf ground for a base fed half wave. A decoupling
section with radials is an option to reduce feedline radiation..Not
required to work though. MK

You lost me Mark. You have a vertical half-wave wire fed at it's base.
You have an unbalanced L/C network which matches the very high
feedpoint impedance to, say, a random length of 50 ohm coax. What do
you do with the coax braid and the ground side of the tuner?

Brian w3rv

Using the usual "gamma loop" feed I generally prefer for those, the coax
shield is connected to the "ground" side of the single turn coil. "appx
9-11 inches dia. for a 10m version" I usually make these from 3/8
tubing... That point is at ground potential as far as the mast, base
support, etc..The other side of that coil is connected to the base of
the radiator. The center conductor taps the single turn coil at the
point for best match. A capacitor from ground to coil "hot" side is
optional. In general you use about 50 pf for a 10m version. Double for
20m, double again for 40m, etc... I use a piece of coax for those. "open
end, don't short" For 10m, it's only about a foot or so long...Look at a
cushcraft 10m ringo. "model AR-10". They have PDF manuals on the web
with pix..That is the same basic design I use. They also make 2m
versions...BTW, I make these from tubing, and are self supporting.
Rarely use wire...These antennas work quite well. Good 10m antenna...The
higher, the better..Add decoupling, even better, but not required to
work..MK

OK, I see what you're up to. Over the years I've had a plain Ringo and
two Ranger versions for 2m and yes they work well. They do tend to
induce a lot of RF in the feedline though.

Tnx,

w3rv

On Thu, 17 Jun 2004 05:30:19 -0800, "mike sebring"
wrote:

I live in S.E. Alaska on an island that is about 99% solid rock and i am
wondering what would be a good way to get an effective ground for my rig and
my antennas.
I have tried to drive a 4' ground rod in the ground and it will only go down
about a foot and a half till it hits solid rock.
I have considered just burying several strands of heavy bare copper wire and
using that for my ground.
Any sugjestions????
Thanks for any help any of you can give me.

EX WB8RSH soon to be KL7???

Mike


Mike, I live on a rock here in central Texas. My service ground is 75
feet of #6 copper laid in the bottom of the electrical trench. I also
have a 6-foot horizontal ground rod laying on the rock with a few
inches of dirt over it and located where the feed lines pass through a
grounded metal bulkhead in the house wall.

The tower ground is via a couple of horizontal ground rods driven
between a couple of layers of rock near the base of the ower. The
tower is pretty much the highest object within a 0.75 mile radius, and
I've had one hit in the past 15 years. The only serious damage was
the stinger on the 2M Isopole at the top of the tower, and the
processor in the PK-232.

My neighbor had lightning rods installed on her metal-roofed house,
and they brought all of the ground cables down to several 2-foot
square copper plates laid right on the rock and covered with a few
inches of dirt. (Capacitive coupling?)

For RF ground, your best bet is radials and counterpoises.

Good luck,
Ed Bailen - N5KZW

On Thu, 17 Jun 2004 05:30:19 -0800, "mike sebring"
wrote:

I live in S.E. Alaska on an island that is about 99% solid rock and i am
wondering what would be a good way to get an effective ground for my rig and
my antennas.
I have tried to drive a 4' ground rod in the ground and it will only go down
about a foot and a half till it hits solid rock.
I have considered just burying several strands of heavy bare copper wire and
using that for my ground.
Any sugjestions????
Thanks for any help any of you can give me.

EX WB8RSH soon to be KL7???

Mike


Mike, I live on a rock here in central Texas. My service ground is 75
feet of #6 copper laid in the bottom of the electrical trench. I also
have a 6-foot horizontal ground rod laying on the rock with a few
inches of dirt over it and located where the feed lines pass through a
grounded metal bulkhead in the house wall.

The tower ground is via a couple of horizontal ground rods driven
between a couple of layers of rock near the base of the ower. The
tower is pretty much the highest object within a 0.75 mile radius, and
I've had one hit in the past 15 years. The only serious damage was
the stinger on the 2M Isopole at the top of the tower, and the
processor in the PK-232.

My neighbor had lightning rods installed on her metal-roofed house,
and they brought all of the ground cables down to several 2-foot
square copper plates laid right on the rock and covered with a few
inches of dirt. (Capacitive coupling?)

For RF ground, your best bet is radials and counterpoises.

Good luck,
Ed Bailen - N5KZW