Ian Jackson wrote:
In message , dave
writes
Ian Jackson wrote:

You should at least provide a good ground for the coax screen at the
antenna feedpoint. Hopefully, this will be remote from the house. For
good luck, you can also ground it where it enters the house (and
anywhere else you care to along its length), but it's the ground at
the antenna end which is the most important.

I've never bothered and have had good results.

I'm sure you have. However, it's nice if the 'feedpoint' of the antenna
goes through the primary (high impedance) winding of the un-un, and
straight to a good RF ground. And, as you have a good RF ground, you
might as well connect the coax screen to it too. The screen should
remain pretty well RF-dead all the way back to the receiver, but there's
no harm in grounding it at other points along its length to ensure
absolutely zero pickup of noise on the coax.

Once the feed point is in the air, the "ground" lead is a "good RF
ground" at some frequencies, and half an asymmetric dipole on others.
Grounding it at several points won't help at some freqs, specifically
those where the distance to real ground (or between any other elements)
is 0.25 wavelengths. You quite possibly will have more of an antenna
than a ground.