HF signals are usually not predominantly polarized more horizontal or
vertical.

The effect that you are seeing is due to the effective height of the dipole
above ground. On 40,20,15,10 the dipole is high enough (in terms of
wavelengths)
that it develops a good pattern at lower angles of radiation (or reception).

On 80 and 160 meters, your dipole is too close to the ground for it to have
a
good low-angle pattern.

Thus what you are seeing is that the signals you want to listen to are
arriving
at an angle lower than what your 80/160 meter dipoles are effective at. The
vertical
antenna has a lower angle of reception on these bands than the dipole.

If you listen to signals out to ~300 km on 80 meters, you may find that your
dipole
outperforms the vertical because those signals are arriving at your antenna
from a
fairly high angle.

-- Tom



"Kristinn Andersen, TF3KX" wrote in message
om...
I have an inverted-V, approximately resonant on 40, 20, 15 and 10m.

I have tried numerous verticals for comparison, but on these bands the
inverted-V always receives signals on these bands better or equally
well, at best. The verticals have been well grounded (using a "large,
good quality" metal sheet roof as the ground) and I have done my best
to minimize losses. The verticals have been anywhere from 1/4 to 5/8
wavelengths long. But they are always outperformed by my inv-V on
these bands. Only on 80 and 160m are the verticals better.

Now, this leads me to wondering if the radio waves arriving at my QTH
tend to be largely horizontally polarized on the higher frequencies?
Or can there be any other explanation that "good" verticals, even 5/8
wavelengths long are never better than the inv-V. Any thoughts?

The verticals and the inv-V were all mounted on the metal roof of my
house. The house is located in a poor-quality ground area (rocks,
shallow vegetation), the direction to Europe is across a low hill
approx. 1/2 mile away while the direction to America is across the
open sea approx. 1/8 mile away from my house.

73 - Kristinn, TF3KX