jawod wrote:

I know this has been addressed on the group before but I remain confused.

I will string a dipole in the trees. The coax shield will be earth
grounded, as well as the balun and lightening arrestor.

Now, in the 2nd floor shack, I've read that running a ground line from
equipment 15 feet or more (in this case) to an earth ground will bring
RF into the shack and be a potent source for TVI, etc.

My choice, then, is to use the ground on the mains.

Given that the shield is earth grounded on the antenna and the equipment
is grounded to the mains, isn't this a good scenario for ground loop?

Seems like a catch-22.

My own gut says safety first, lower risk of RF issues after-the-fact by
? what ?

I remember suggestions of coiling the ground wire in an RF choke,
multiple ground lines of various lenghts to mess with harmonics.
Ferrite beads? Chicken blood and a black cat?

John


John,

So you are taking a balanced aerial, a dipole, chuck it onto a balun and the
feed it with a coax. Nothing wrong with that...

There should not be any "involvement" by the coax in the functionality of
that dipole. The grounding of the coax are for shielding purpose only and
as such, you ground the coax at one of the terminations, in your case, the
transceiver.

Building regs normally demand that the house's mains ground should be
connected to a ground rod somewhere, normally at a central point.

Assuming that every level adds 2.5m, you are sitting 5 meter up. Even if you
ground your rig with a separate connection to a ground rod, you'll still be
electrically 5 meter away from ground ( at least ).

You will always have RF in your shack PERIOD, It's just a question where
it is and how you discover it. It's either RF current or RF Voltage. As the
RF voltage is what you normally discovers by having a "hot" key or
transceiver, you need to phase shift the ground connection of the coax in
time so you have a max current at your rig instead of high voltage.

This is solved by using an artificial ground. Buy or build one, they are
dirt simple. MFJ sells one.

The artificial ground is basically a capacitor and an inductor in series
with the coax SHIELD(!). Both cap and coil is variable/tunable.
By changing the cap and coil, you can move the RF Voltage and RF current +/-
90 degrees. You just adjust for max RF current at your operating frequency.

This worked fine at the 32nd floor for me...


Cheers


Dan / M0DFI