On 3/19/2019 11:01 AM, Hans Hammarquist via TowerTalk wrote:
Hi John,
I believe you have a close to ideal situation regarding grounding. I wouldn't
be surprised if some grounding rods into the clay would work well at RF.
WRONG! A connection to mother earth does NOT make transmitting antennas
work better. The earth is a big resistor -- connecting to it burns
transmitter power. The ONLY reason for a connection to earth is
lightning protection. RX antennas are an exception -- many depend on a
connection to ground.
Radials and "ground screens" serve two functions -- they provide a low
resistance path for return current and the fields created by a vertical
antenna, and the SHIELD those fields from the lossy earth. K2AV's
folded counterpoise provides the return path, but provides no shielding
function.
I would just use a "nine tail" groundplane. I have used that extensively at
Fied-days. I have about 10 wires, 10 feet long that I spread out around my tent as a
ground. Never had a problem.
And it never did anything useful either.
(I use a short ground rod for the generator as you need a good ground at 60Hz
for that.)
A short ground rod is not a good ground at 60 Hz, or at any other
frequency. A ground rod for the frame of a generator CAN reduce noise
from the generator, but so can a good common mode choke on the AC
cable. The one we use is shown on page 23 of http://k9yc.com/RFI-Ham.pdf
I believe you have the right ground for a phased antenna and you will not need
chicken wires to improve your ground.
I believe you need to study the ARRL Antenna Book and N6LF's website.
73, Jim K9YC
73 de,
Hans - N2JFS
-----Original Message-----
From: John <w5jmw@towerfarm.net>
To: TowerTalk@contesting.com <TowerTalk@contesting.com>
Sent: Sat, Mar 16, 2019 8:14 pm
Subject: [TowerTalk] ground,good or bad ?
I am wondering about nr of radials to run.I understand that over water you sometimes
hurt things by adding radials over water…
At our new qth (3 yrs) I am finallyn putting up the vertical phased antennas for 80 meters.We live in an area
that has clay down abt a foor to 6 inchs below.Our water from ¼ in rain stays around for days.then
the ground is moist for abt a week.We dug a trash burn pit abt 6 mos ago.Abt 6 ft deep by 10 ft…It is
full of water..Our last rain was 4 sdays ago…it’s not draining well due to the clay.Is this
considered a good ground? Are radials a good idea ?thanks,john w5jmw
Sent from Mail for Windows 10
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