Bill Ogden wrote:
I understand that E and H fields are intrinsic parts of the same thing (for
radio waves, etc), and I am not trying to separate them along the lines
discussed by some list participants.

I would think that the E and H ratio of 377 is a function of the SI units of
measurement involved. It would seem that there is the same amount of energy
(at different and selected instances) in the E and H waves, and different
units of measurement could produce a ratio of 1:1 (or anything else, with
appropriate units of measurement).

Yes, that's correct. What I tried to do in my explanation was to relate
the E/H ratio near a small loop with that of free space. That makes the
units of measure immaterial.

To return to the ferrite rod antenna: Ignoring the directional null
capability (which might be very useful in some real-world circumstances) is
there any advantage to a small ferrite rod antenna over a short wire antenna
(assuming perfect amplifiers, as needed, following the antennas and assuming
160m or 80m usage)?

You get a greater effective aperture (aka "capture area", and directly
related to "effective length") from the ferrite rod antenna for a given
physical size. This results in a larger signal for a given impinging
field strength. If you had perfect amplifiers, that would make no
difference, but real amplifiers generate noise, so a larger signal
results in a better signal/noise ratio when you're at the level where
the amplifier noise dominates the system noise figure. But if the signal
level is large enough so that atmospheric noise dominates, having a
greater aperture doesn't present any advantage.

As mentioned earlier, there have been a number of construction articles over
the years explaining how a ferrite rod antenna did wonderful things for
160/80 operation. I have wondered if these results are generally valid, or
were the result of the authors' pride in their works, or happened because
the directional null abilities solved a local problem.

Anecdotal reports of "wonderful things" should always be highly suspect,
and placebo effect high on the list of possible causes. It might be
easier to get a good null with a ferrite rod antenna than with a
casually built antenna of some other kind, and that would be a big
potential advantage.

When considering the value of anecdotal reports, consider the widely
reported benefits of various kinds of speaker cable, and the staggering
amount of money that's being extracted from the believers.

Roy Lewallen, W7EL