Jack Painter wrote:

"starman" wrote

A low noise inverted-L will have the vertical downlead at the far end of
the horizontal section with the balun located at the lower end of the
single wire downlead, near the ground. Then you can run coax back to the
house from the balun. The near end of the horizontal section shouldn't
be too close to the house where it might pick up noise.

The 'low noise inverted-L' (paragraph above) can make a big difference
in lowering the noise that the antenna picks up from local sources.


There is not one ounce of truth to an "Inverted-L" being ANY quieter than a
45 degree random wire, and especially a horizontal-dipole, which is
generally quieter than any antenna with a vertical component. Most
interference is vertically polarized, and the verticals, random-wires,
slopers, or inverted-L antenna designs all pick up more vertically polarized
"noise" than a horizontally polarized antenna. Adding a vertical or even a
45 degree sloped component to an antenna DOES make it less directional than
a horizontal, and that is all it does. Any noise-limiting realized from
these designs comes strictly from the grounded-Balun and not the design,
configuration or dimensions of the antenna. Shield-grounding (for static and
lightning protection) at the feedpoint will achieve 99% of the
noise-limiting benefit that a grounded Balun does. The missing 1% is an
equal loss of signal and noise through the Balun. All RF noise (but not all
energy has RF components) is coupled right across the Balun windings, their
function of electrically decoupling is true of some DC energy, but not RF
energy, which is rather efficiently coupled across the Balun by design.

The same application of a grounded-Balun works equally well on both the
random (straight) wire antennas and inverted-L antenna btw. Both the random
wire and inverted-L benefit from (require in most cases) a counterpoise
ground or radials to provide effective transmitting. Neither a counterpoise
nor radials affect reception from the either the random wire or inverted-L,
however.

I think you've missed the point. A so called 'low noise' inverted-L is
intended to reduce noise on the feed line to the receiver which comes
from domestic sources like appliances in the home. This is not the same
as the noise being received by the antenna wire itself. When the feed
line is part of the vertical section of the antenna, like the typical
inverted-L or random wire, it can pick up noise from the domestic
environment. The solution is to use a coax feed line which connects to a
balun near the ground. The vertical section of the antenna comes down to
the balun. This allows for a short RF ground from the coax shield to
earth which decouples the noise on the shield.