dave wrote:
Jim Lux wrote:


Do you use a balun at the antenna
feedpoint? How do you tune the inverted-V?

Good RF chokes on the coax at the feedpoint and at the point of entry
would go a long way to eliminating any "RF in the shack" problems. A
couple 2.4" 31 mix cores with half a dozen turns on them, for instance.

Whether the V is tuned or not won't have any effect on RFI or grounding.

A BalUn would help a lot.

Balun/choke.. tomato, tomato.. they're really all the same thing. Keep
the RF off the outside of the coax.



Since we are sticklers for the NEC, Homey needs a #6 wire from where the
transmission line enters the dwelling to an 8' copper clad rod driven
into the earth, as close as practicable.

The communications system (be it CATV, net powered broadband, amateur,
etc.) would need to be bonded to any of the usual things that form the
grounding/bonding system,e.g, one could "ground" through the metal conduit.

A ground rod is, of course, not recommended in the current codes as a
made electrode, and in any case, the code doesn't necessarily require a
specially installed ground for this purpose. If you DO install another
ground, then it has to be bonded with AWG #6 copper (or bigger) (can't
use the conduit)

Telephone has different rules. Must have electrode/grounding means as
close as practicible to point of entrance, and the ground wire has to be
AWG14 or large, insulated, in as straight a line as possible.

Metal structure supporting outdoor antenna systems have to be grounded
with AWG10 or bigger copper, AWG8 aluminum, or AWG17 copperclad steel,
straight line. (the size requirement is for mechanical strength, not
conductivity, which is why the copperweld(r) can be smaller)

So you have these weird situations where the phone protection block has
to be connected with AWG14 insulated to a grounding electrode as close
as practicible, but then, because of the "bonding of electrodes" rules,
you have to connect that electrode to the "house ground" with nothing
smaller than AWG6.

CATV is even different.. grounding block for drop has to be grounded to
an electrode close to block and an *insulated* AWG14 or bigger run to
bond with the rest of the house's grounding system.


This sort of thing is why most ham installations aren't "code
compliant"... heck, you could go insane trying to wend your way through
the thicket of rules for the NEC. And that doesn't even begin to get
into the transient suppression guidelines and/or NFPA 780 lightning
protection rules.