The confession of a ham with no ground wire in his shack other than the AC
mains follows. The shack is on the second floor and any ground line would
be eighteen feet in length minimum. This house is long at about eighty
feet to bond to the main AC mains ground rod would take a run of nearly 100
feet added to the eighteen feet already mentioned. Ireland has a low
incidence of electrical storms and my practice is to disconnect the antennas
when not using the radio. If I am going away then everything is also
disconnected from the AC mains. The antennas are all balanced and there is
no RF causing problems in the shack. I suspect you will find that many
people operate in this manner for years without any difficulty.
Perhaps I should at least purchase some six inch wide ground strap from
Georgia Copper and run it down the eighteen feet to three or four ground
rods beneath the shack. There is not much likelihood that I am going to
rip up a concrete walk around the house to install a 100 foot long
connection to the household mains ground. Should I just continue without a
ground or is it wise to use an external ground not bonded to the household
mains ground except through the shack wiring. I can remember operating
from a third floor shack and apartment dwellers must really have
difficulties. Over many years of operating I have been fortunate and never
had a problem.
Operation here is on 160M through 2M. The inverted L is up to 100 foot
above ground but returned to ground. The four element SteppIR Yagi is at
80 feet these two towers are separated by 250 feet.
73 Doug EI2CN
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Jim Brown
Sent: 17 June 2010 17:10
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Shack ground
On Wed, 16 Jun 2010 22:08:24 -0400, Mickey Baker wrote:
>K7DD is right. Bond to your SPG with as big a wire as you feel you can
>afford.
Right.
>Longer path = bigger wire.
WRONG! Lightning is NOT a DC event. It is a TRANSIENT, with its energy
centered around the AM broadcast band and extending for several octaves
either side (that is, from about 200 kHz to about 5 MHz). INDUCTANCE is
what matters, and that is proportional to length. The only benefit of a
bigger conductor is that the conductor can discharge more of the event
before it vaporizes. :)
73, Jim Brown K9YC
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