Well....as in everything there are pros and Cons
You looking to do this as a base i take it
Also looking to use HF frequencies
Circular polarity in some cases are the Best
in many cases not
For HF frequencies they are extremely large
Circular beams are more for VHF and UHF
(particularly for satellites)
i didnt look at link to your antenna
elsewhere on the thread it was mentioned that it actually wasnt a circular beam
However you did ask what if any advantages there are to that antenna
if you have 2 people talking on a beam and both are set up on the flat side (horizontally )
then those 2 people will find it fairly easy to talk to each other
they may even find that other people (using vertical antennas) do not or can not hear them
most antennas are vertical in their radiating signal
as such these vertical antennas also receive best (typically ) vertically also
beams (most of which are horizontally radiated) concentrate the power they radiate in a far smaller slice then that of a typical vertical (which is usally a 360 degree footprint)
many beams are set as vertical so they gain the greater concentration of power radiated in their desired slice (beam-width)
the reason or advantage to using a vertically radiated beam is that most other antennas are that most other antennas are vertical (ground planes or dipoles)
as such they easily receive the whole signal from the other vertical antenna
think of say a skinny person
talking to you standing in front of you
you see their entire body (shoulder to shoulder)
if however you remain as you are and the other person turns 90 degrees from you
although you will still see them
you will see far less of them and not see anywhere near the amount of detail you had seen
when both of you were directly facing each other
(now if that person was a block from you you would see and recognize far less)
Now back to the antennas
think of a cross
where the vertical and horizontal meats it is a simple dot for the most part
if i had 2 vertical or 2 horizontal antennas some 500 feet apart
then both antennas would see each other very good
(same for the signal being radiated between them)
now go vertical to horizontal and suddenly one antennna does not persay see the other
(or hear the radiated signal of the other) anywhere as well as when
2 verticals or 2 horizontal antennas saw each other
so in best world happenings
2 verticals will talk best to each other
or 2 horizontal antennas will talk best to each other
but what happens if the 2 like antennas are no longer simply 500 feet apart
what if not even 5000 ft apart
what if is 500 miles or more apart
then at this point many other factors come into play
now what started as a vertical or started as horizontal signal
is now bounced around and or reflected off other parts of the atmosphere
in other words
light travels only in a straight line
yet put a mirror in its path and we can turn or rather reflect it to a different location
back to signal from antennas and the atmosphere does this to a antennas signal
by water and gas molecules or different layers heck even planes and such
so now what may have started as vertical signal radiated from a vertical antenna may well have been reflected or scattered into many other directions then the signal was originally sent
typically though
vertical stays radiating vertical
horizontal stays horizontal
so if a vertical is talking to a horizontal antenna
then because of the differences the antennas give out and receive signal
then there is either a loss between different planes of radiation
(or no loss between antennas of same plane of radiation)
the actual number if memory serves me is 3 DBi or Dbd difference
Now finally to your circular beams
it or they are using both planes
as such they are only ever at worst 1.5 DBi or DBd
they also have the most consistent signal going through the atmosphere
given the are both equally in vertical and horizontal planes
a circular beam may well realize the least amount of fade in a signal
however due to the size needed they are typically not used often for HF or mobile
if you look at say ham bands in the VHF or UHF
you will notice nearly all repeaters are having their signals sent out via vertical antennas
but most contesting or DXing is used with horizontal antennas
(rarely do the 2 planes mix)
most satellite work is used with true circular beams
(then there are many variations of these antennas)
to realize ho best to use these antennas
happy hammer's link was rather good
http://www.qsl.net/sv1bsx/antenna-pol/polarization.html
I tried to keep the math out of it
and give you a bare bones answer to your original question
