----- Original Message -----
From: "Tom Rauch" <w8ji@contesting.com>
> > I'm considering buying my first amplifier (after almost 30 years
> barefoot).
> > I've always heard that running your rig from the 2nd floor of your house
> > is risky because you can't get a good ground.
>
> The idea you need an "RF ground" on equipment is largely a myth brought
> about because people insist on feeding antennas incorrectly. If you have a
> reasonably proper antenna installation there is virtually zero RF on the
> cabinets anyway, unless you use a single wire feeder.
>
> What people often do is sometimes insist on feedline a dipole with
> unbalanced line, a vertical with much less than perfect ground with coax,
or
> bringing a feeder away from an antenna in parallel with the radiator and
NOT
> using a choking device to remove common mode currents.
>
Speaking from experience, where you get into trouble is with
overhead coax lines and control cables that people sometimes
use in second story installations. At one of the clubs I operate
from, we have towers on top of buildings, and by necessity
coax cables and rotator control cables are run back to the
2nd floor shack on above ground (25 to 40 ft high)
messenger cables. There is no RF ground per se at the
shack. Most of the time everything works fine, but occasionally,
we have some trouble when we are beaming towards the
overhead messenger cables with some of the lower
monobanders (5 element 20M at 70' in particular). The
band-aid fix has been to bond various afflicted items together
with short ground straps so that they are at a common RF
potential (we were having a lot of trouble with our Array
Solutions SO2R box). Long term we need to add RF common
mode chokes to the feedlines and control cables before they
enter the shack (this is a lot more work, so I haven't done it yet).
73 de Mike, W4EF....................
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