On Wed, 22 Dec 2010 05:13:39 -0800 (PST), Richard Fry
wrote:

Observations from watching the YouTube video...

The gain units used in the video are therefore unconventional, and
need further
definition.

Hi Richard,

Leave it at unconventional - that word's definition is well
understood.

3. The relative field radiated by a conventional 1/4-wave vertical
monopole
driven against a perfectly conducting ground plane always is maximum
in the
horizontal plane. Such a system radiates virtually 100% of the matched
power
applied to its input terminals.

This reveals a common flaw found in vertical antenna analysis when
compared to AM antenna measurement conventions. Simply put, if you
lift the antenna off of an infinite plane, you lose 3dB. It is
demonstrable with even the meagerest of antenna modelers.

Chip's antenna is in the air, not on an infinite plane. A solid disk
replacing a field of radials does NOT constitute a replacement for an
infinite plane such as to recover the 3dB. This might account for the
bookkeeping error in the vendor's favor.

I believe somewhere in the tightly scripted presentation it was
asserted that there was no "figure 8" pattern as one would expect of
an antenna in free space.

The antenna is "apparently" in an anechoic chamber - or free space as
closely as can be approximated. There are no reports of the far field
envelope shape.

So let's mark it up to Chip's usual technique of loose suggestion
being passed off as a citation to then be wrapped back as a proof.

Therefore the peak gain of that antenna system at resonance cannot be
improved
by putting a sleeve of any kind on the monopole.

I would dispute that. The evidence is sufficient insofar as the
indication of change in the before/after display on instrumentation.
Unless this is some form of parsing what "peak gain" means. What you
write immediately following already conforms to that instrument
display:

The sleeve may change the shape of the radiation pattern of the system
without
the sleeve, though, which could change the field intensity at the
location of
the receiving antenna used in the test. This could account for the ~3
dB
improvement shown in their results when using the sleeve.

And by what you say above, this is the entirety of it. A thicker
radiator - nothing less than has been covered in text for decades. You
observe that below.

4. Nothing is shown in the video about the amount of matched power at
the
feedpoint with and without the sleeve. If that is not held constant
then the
test will be flawed.

The instrumentation already takes care of that, and is discussed early
in the presentation. I was doing this kind of bench work, with this
kind of instrumentation, in this band, 20 years ago.

5. The VSWR bandwidth of a monopole may be increased simply by using a
larger
cross-section conductor of "non-fractal" construction.

Of course - but that information doesn't sell product.

73's
Richard Clark, KB7QHC