On Fri, 11 Feb 2005 13:44:48 -0500, "Robert11"
wrote:

a. What is plotted in these diagrams; the H field, the E field, or the
resultant of the two ?

Presumably E Field.

b. When they talk about field strength, what do they mean ? Again, the H
field, or... ?

That should be expressed in the units consistent with H or E. If no
units are expressed, then it is usually a comparison with dB, dBi, or
dBd.

c. Have a receive-only antenna running around the 4 sides of my attic. Open
at the end. Should I tie the end to the beginning, making a horizontal loop up
there, or not ? Why ?

Yes(No). It is (is not) important.

d. Do listening only, from 0 to 30 MHz, and from all compass points.

-Oh- Well that changes everything!

Would a straight run of wire along one side (thus foresaking the
lengths provided by the other 3 sides) gain me anything, or is the square loop
configuration probably the best overall compromise for pulling stuff in ?

This changes even more!

e. Tried to find some but couldn't.
Any pix/diagrams on the web showing the lobe patterns as a function of
frequency for:

a single random-length wire
a 4 sided loop, open at the end, like I now am using
a 4 sided loop, closed at the end

Hi Bob,

The same geometry at all the different frequencies you propose do not
yield the same lobe patterns. That is your first lesson.

You express the desire to receive from all 360° which will certainly
happen for many of the designs you describe above, but only through
happenstance and being in the attic (which means close to ground, as
in earth, not wood/stone/mortar).

What you want to concentrate on is keeping noise out of your antenna
(this will probably be answered in the course of the thread).

The long and short of it is without spectacular care, those lobes are
rarely observed unless you have your antenna in the air, and more than
a quarter wavelength above ground - difficult to do with your
from 0 to 30 MHz,
....Quarterwave of 0MHz is pretty high up.

A simple dipole is handy, so is a loop, and so is an open loop, as is
a vertical, or phased elements - but only with respect to their size
at any particular frequency.

Your basic question is far more complex to answer than any complex
question which often resolves to a simple yes/no.

73's
Richard Clark, KB7QHC