[RFI] RFI: TORCHIERE TORTURE!
jim at audiosystemsgroup.com
Fri Dec 21 01:57:03 EST 2007
On Thu, 20 Dec 2007 20:22:57 -0800 (PST), Michael Germino wrote:
>Get a different RF ground for your antenna. The random wire is 1/2
>of your antenna, the other half is the AC ground wire of your
> I would be surprised if the lamp is your only RFI problem. Your
house must have RF all through it.
> A RF ground is not a ground rod.
>I would run the ground wire (of the tuner) to the ground (soil) out
>side and then run radials out from it on the ground (dirt).
NO, NO, NO! The EARTH is important ONLY for lightnihg safety. It
has NOTHING to do with the operation of an antenna or keeping RF out
of anything. You DO need an earth connection for anything that might
get lit up by lightning (including a lightning protection device in
the antenna feedline).
We DO need a counterpoise for the antenna. You're right, house
wiring is a lousy counterpoise, for the reasons noted. BUT: the
place to connect them is at the place where the antenna starts,
which in the case of a long wire that ends at the tuner, is the
chassis of the antenna tuner. So the "common point" for radials is
the chassis of the tuner.
>I wouldn't use the ground lug on the radio,
Nor would I -- I would use the chassis lug on the tuner for the
counterpoise for a long wire that ends in the shack.
>I would put an RF choke between the tuner and radio.
If you mean a common mode choke on the coax, that's not a bad idea.
But that's also where I would put the lightning protection device
for a long wire antenna that ends at the tuner -- I would put it on
the radio side of the tuner.
>(On the second floor you won't find a RF ground for your radio)
Nor do you need one.
What we DO need is a serious earth connector for the shack that is
also bonded to every chassis in the shack AND to the green wire(s)
in all the power outlets that feed your shack. It should also be
bonded to ground in the main AC panel (that is, where power comes
into the house).
Jim Brown K9YC
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