[TowerTalk] Fwd: Grounding of tower
K1TTT at ARRL.NET
Fri May 10 16:04:12 EDT 2013
A corollary to this is: There is no such thing as a ground for lightning.
You can kind of get away with pouring a bit of household 60hz into the
ground, but don't count on it to work for a primary on a power line either!
David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net
From: Jim Brown [mailto:jim at audiosystemsgroup.com]
Sent: Friday, May 10, 2013 17:17
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Fwd: Grounding of tower
On 5/10/2013 9:29 AM, George Dubovsky wrote:
> 3. "RF ground system" is a perfectly good term and is accepted and
> understood in the rf design community.
I strongly disagree -- it has led to HUGE misunderstandings and TERRIBLE
errors in the construction of equipment that are so widespread that they are
accepted as the only way to do it, and are a major cause of hum, buzz, and
RFI. It causes people to think that ground rods are a desired part of an
It also causes people to think that separate grounds for RF, audio, and
power are somehow a good idea. And it causes people to view a connection to
earth as a cure for all ills, including, but not limited to, RFI, TVI, and
antenna performance. And that the earth is somehow a sink into which noise
and RFI can be poured.
What REALLY matters to the RF design community is keeping track of where the
current flows, and that means ALL the current -- DC, audio, and RF
-- on every cable. Henry Ott says this quite poetically when he speaks of
"the half of the schematic hidden behind the ground symbol." Is the
reference PCB layer under microstrip complete, or is it broken for a extra
trace that wouldn't fit (or was forgotten) on the main layer?
Does the cable shield go directly to the shielding enclosure, or does it go
to a circuit trace to create a "Pin One Problem" YOU may not have made
these errors, but the vast majority of equipment is built with these faults.
If you re-read my post, you will see that I wasn't objecting to the
connection of the common point of a radial system to a ground rod.
73, Jim K9YC
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