Just visualize that your 30 ft length of wire from your station to "ground"
puts your station near the HV point or nearly 1/4 wave above ground for 40M.
If one has RFI issues on one band and not on others, this could likely be
the reason.
I agree with Jim on all of this. Many antenna systems require a ground
reference for radiation efficiency AND lightning protection. And all of
this should be outside of the structure, NEVER inside!
At the same time, a center fed dipole or a beam is in itself a complete
radiating system and requires no ground at all to be an efficient radiator.
On the other hand, antennas such as verticals, end fed wires, slopers to
name a few do work against earth/ground which serves as the other 1/2 of the
antenna system. This is the reason radials are typically used with
verticals be they at the surface of the earth or elevated as in a ground
plane antennas.
RFI issues are typically the result of wiring within the station, acting as
an antenna itself, picking up RF as radiated from the transmitting antenna
or antenna loads that produce a highly reactive condition at the station.
In both of these cases, grounding is not the solution.
I also don't subscribe to the idea of a tuned ground system or artificial
ground. For one, tuning will change from band to band and in some cases
frequency within the wider bands. Also, as one described, radials of
various lengths spread around the room can have quite high voltage at their
ends which in itself can produce some nasty RF burns or contribute to
accidents or fire.
73
Bob, K4TAX
----- Original Message -----
From: "Jose F Ballester" <jfballester@gmail.com>
To: <k9yc@arrl.net>; "Discussion of Ten-Tec Equipment"
<tentec@contesting.com>
Sent: Wednesday, May 16, 2012 9:57 PM
Subject: Re: [TenTec] RFI Issues
I'm 30' from a copper plated ground rod connected with a 10 gauge braided
copper wire from my second story shack. Never detected a difference when
it has been disconnected. Don't have grounded antennas.
Why is it necessary?
73 de Pepe WP3HW
On May 16, 2012, at 10:49 PM, Jim Brown wrote:
On 5/16/2012 12:22 PM, Stuart Rohre wrote:
Likely with a second floor shack, ONLY the tuned ground lead would help
your RFI.
Repeat after me:
A CONNECTION TO EARTH HAS NOTHING TO DO WITH RFI.
A CONNECTION TO EARTH HAS NOTHING TO DO WITH RFI.
A CONNECTION TO EARTH HAS NOTHING TO DO WITH RFI.
A CONNECTION TO EARTH HAS NOTHING TO DO WITH RFI.
A CONNECTION TO EARTH HAS NOTHING TO DO WITH RFI.
A CONNECTION TO EARTH HAS NOTHING TO DO WITH RFI.
A CONNECTION TO EARTH HAS NOTHING TO DO WITH RFI.
A CONNECTION TO EARTH HAS NOTHING TO DO WITH RFI.
A CONNECTION TO EARTH HAS NOTHING TO DO WITH RFI.
What matters is proper bonding of cable shields to the chassis of the
equipment to which it is connected, and the proper bonding of every
equipment chassis to each other.
73, Jim K9YC
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