Several points:
(a) I did not mention any connection to earth for ground, and;.
(b) I did discuss in detail bonding or grounding related to power for the
station.
(c) I did mention that ground wires or conductors can radiate or receive RF
(d) I've worked in professional audio for most of my life and dealing with
both balanced and unbalanced systems. I don't have a clue about "pin 1"
problems as I've never encountered it. I figure it is like RF ground,
likely a factor that doesn't exist in science.
73
Bob, K4TAX
----- Original Message -----
From: "Jim Brown" <k9yc@audiosystemsgroup.com>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Friday, April 03, 2009 11:35 PM
Subject: [TenTec] RF Ground
> >
>> Do recall that any station ground has length and inductance and
>> impedance.
>> It may be a good DC ground as it has low resistance, but is it a good RF
>> ground? In almost any condition, the station is above RF ground. For
>> example, a station ground that is some 16 ft in length puts the station
>> at
>> 1/4 wave above ground on 20M. That 1/4 wave ground wire can radiate or
>> receive noise just like an antenna.
>>
> The words "RF ground" have NO MEANING in science. They are a fignewton
> of fuzzy thinking. A connection to EARTH is totally irrelevant for a
> radio transmitter, receiver, or antenna. A connection to earth is NOT
> part of a solution to RF interference, hum, buzz, or noise. A
> connection to earth does not make an antenna work better. It only
> provides lightning protection. That's very important, of course, and
> to do that, ALL ground rods must be bonded together by that low
> impedance path, and all wiring that enters a building must have its
> lightning protection bonded together and to that network of ground rods.
>
> For two reasons, that bonding together also minimizes hum and buzz
> related to the power system.. First, pin 1 problems. Second, unbalanced
> wiring. Both couple noise current into equipment.
>
> The EARTH is a LOUSY antenna element, because it is lossy (resistive).
> Any RF current flowing in the earth is lost as heat. We use radials with
> vertical antennas to prevent current from flowing in the earth, and
> allow it to flow in low resistance copper instead. The vertical antenna
> is trying to produce an EM field, and the radials complete the path for
> that field (and for the antenna current). Only a few resonant radials
> can serve that purpose if they are high above the earth, but it takes
> MANY radials to do that well if they are very close to the earth. Those
> radials are not RF GROUND. Over the years, we have confused ourselves by
> calling them a ground system, or a "ground plane." They are not. They
> are part of the antenna!
>
> 73,
>
> Jim Brown K9YC
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|