View Single Post
  #10   Report Post  
Old August 25th 03, 01:41 AM
Reg Edwards
 
Posts: n/a
Default

The previous posting, of course, applies to RF grounding of the radio shack,
particularly to end-fed antennas where at some frequencies there may be
appreciable RF currents flowing from the shack down to ground via the very
uncritical arrangements previously described.

If there are any local or national regulations to be complied with regarding
the domestic power frequency safety ground then they should be complied
with. But in general such regulations, by themselves, will fall far short of
an adequate radio ground.

For example, a single safety ground rod, wherever it is located, will likely
have a resistance at all frequencies greater than 50 ohms plus the important
inductive reactance of all the wire between the shack and the rod. By all
means include the rod in the station's RF ground system but it will be found
to be amongst the ground connections which can be disconnected without
having any effect on station operation such as tuner settings.

A single rod is no better than a buried horizontal radial wire of the same
length. If a rod is the only RF ground available an endfed antenna will work
in some poor fashion, RF in the shack, etc., unless the local soil is
saturated with salt water - an unlikely condition.

To protect the family home from direct lightning strikes on the antenna then
the mast etc., is best provided with its own ground electrode system. We
have very few thunder storms in the UK. In all my years I have seen only one
lightning strike which hit the ground. So what I have done when a storm
seemed imminent (the tuner capacitor sparking over) is just disconnect the
antenna at the lead-in to the shack and toss the loose end of the wire as
far as I can along the back yard.

For antenna + mast grounding details I leave to more experienced people.
---
Reg, G4FGQ