Topband: Adding a Ground to Elevated Feed Vertical?
billw at waveform.net
Tue Nov 29 16:48:46 PST 2011
Doubtful the ground rod would improve performance any. I wouldn't want
to run the setup without an earth ground for safety though (lightning).
You could do that at the antenna, but then you should also bond it back
to your main house ground. This would lose any ground isolation you have
between your antenna and your station though which might be a problem.
You could just use a protector on the coax near your station and ground
that to your station/house ground.
My boring crews at work charge me $8/foot for medium-length jobs
(1,000ish feet). Don't try to run such a rig yourself -- they are
complicated and if you mess up you can loose rods/bits/sondes
underground and the last two are *expensive*. I did about a 200(ish)
foot run to my vertical in the woods (no messing up of the grass that
way :-), and a new sump pump drain line for about 350 feet total in two
runs and that was $2,000 cash including materials. That was partially as
a favor to me though as I use the crew for a lot of "regular" commercial
work. If you can find a crew in your area you can ask them if they can
help you out between jobs or on a slow day and maybe a get a good deal.
The nice part is I now have a 2" schedule 80 HDPE pipe going to near the
base of the vertical from my shack so it's easy to pull in new cables if
needed. I have a 4awg ground pulled *outside* the duct for
lightning/bonding (I use radials for the RF), and the entire thing is an
average depth of maybe 4 feet or so underground.
Much easier/cheaper is to use "poor mans hydraulic drilling" if you just
need to cross your driveway. Dig a hole on either side of your driveway
and use a small-diameter water pipe sideways with your garden hose
providing some low-pressure water through the pipe. Cut a bevel in the
end of the pipe and use it by pushing and turning it until you get all
the way through. This method works surprisingly well provided you don't
have really rocky ground. You can either just pull the cable/radial
through the hold, or run a piece of conduit (which is probably the
better option). If you just run the wire, you could have a problem with
your driveway cracking over the borehole. The directional drilling crews
use a bentonite clay/water mix to grout the hole and that's something
that's cheap and easy to do on a small scale if you don't want to use
> Hi Gang,
> I've been running my vertical for a couple of weeks now and it plays
> nicely. The setup is:
> 85' up and 42' horizontal.
> Comtek 1:1 balun at feedpoint 7' off ground.
> 3 x ~137' radials all between 7 and 13 feet (driveway crossing height)
> the ground.
> Fed with good coax.
> VSWR at rig end of coax is 1.9:1 at 1830 kHz.
> The question is whether it is worthwhile to install a ground rod under
> feedpoint and connect the neg side of the balun to the ground rod (or
> the shell of the 259 at the bottom of the balun). I'm asking because
> my luck I won't be able to remove the rod once it is in and I cannot
> convert this antenna to ground radials because it is close to my
> OK, I could rent/borrow a horizontal boring rig.....
> Mark K2QO
> K2 #543
> UR RST IS ... ... ..9 QSB QSB - hw? BK
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