Jim - NN7K wrote:
Not to mention that noise is normally a phenonmen
of the Vertical Plane (which , depending on how
steep your inverted "vee" is, will contain some
vertical component, while the yagi/quad is
Horizontal to the plane. This has been a factor
on vhf for years, as noise levels tend to peak
at 6 meters (50 MHz). The MAIN reason that F.M.
is Vertical polarized is that for mobiles, it is
easy to construct an omni-directional antenna.
Most vhf manuals detail this effect! Jim NN7K

Dunno...I don't see much difference as far as the polarity
of the antenna. It's more the polarity of the noise source,
and it's radiator. I've got both horizontal and vertical yagi's
on 2m, and I've seen many times when the local line noise
was much worse when horizontal. But I blame that on the
noise being radiated mainly by horizontal power lines.
I see cases of noise with both polarities, or mostly
vertical, or mostly horizontal. Just depends on the source
antenna. You usually see appx 20db attenuation when
cross polarized.
As far as Ken's loop vs inv vee, if the vee is picking up more
noise, that just means the vee is the best antenna at picking
up that particular noise and at that direction and angle.
If he were to transmit on the two antennas, and receive
them from the noise source, using the sources antenna,
the vee would be received the strongest more than likely.
It's all reciprical. Noise is rf just like any other signal, and
obeys the same rules. If a certain antenna picks up more
rf of any type, noise, or desired, it's the best antenna of the
bunch to receive that source of rf. Thats one reason why I
often chuckle about "noise problems".. As long as it's not
local or common mode pickup from the shack, that just means
the antenna is working, and doing what it's supposed to do.
MK