The company's name was on the original post so it's no secret. You can view
their website at: http://dxblaster.com . The company will even allow an
on-the-air demo of this antenna.
Compare the cage dipole gain against an OptiBeam OB2-80 2el 80m yagi which
costs significantly more. http://www.optibeam.de/ .
John KK9A
To: TowerTalk <towertalk@contesting.com>
Subject: [TowerTalk] Cage Dipole Performance
From: David Gilbert
Date: Fri, 10 Apr 2009 10:02:06 -0700
In response to N3OX's posting on cage dipoles, I searched around to find
more information on them and happened to find the website of a
manufacturer who also claimed better performance than a standard
dipole. I have no idea whether or not this is the same one who had
corresponded directly with N3OX, but I decided to write this
manufacturer directly to see how they derived their claimed results in
order to better understand the design in general, and in particular why
modeling programs like EZNEC don't properly deal with a cage antenna.
I received a very quick response from one of the owners of the company,
and since this person states he is aware of the thread here on
TowerTalk, as well as my own personal skepticism, I am taking the
liberty of forwarding his comments verbatim (cut and paste ... no
editing whatsoever on my part) so that his side of the discussion may
get fair representation.
I won't divulge the name of this manufacturer so don't bother to ask. I
also think it best if I personally make no further comments in this
forum, either supportive or critical, on the topics of field testing or
time diversity in modeling. I will say, though, that I hear as well as
my neighbors.
73,
Dave AB7E
<quote>
Sure the antenna was tested on an antenna range vs a standard resonant
dipole.
An independent engineering company srt up the trst doing firld intensity
measurments in all planes at all practical distance using hewlett packard
spectrum analyzers that are capablr of .1 db resoution.
The antenna was tested at distances of 1,5,and 10 miles. The antenna was
rotated to check all lobes. Reference data was compared at 15 degree
intervals.
Antenna height was 1/4 wave and tested again at 1/2 wave. results were
surprisingly good. In all cases the cage exceeded the standard by 5 db or
better...We were surprised ourselves. However the company used assured us of
the correctness of the measurements. They commonly do proof of performance
testing for broadcast and cable. Their instrumentation is current
calibration
and correctly used by experienced engineers.
Standard modeling programs are based on assumption of single piece radiators
and have no provision for time diversity in them. The cage uses this
phenomina.
When one uses most modeling programs, the results err due to this fact. The
field data reflects the differences.
I have read your tower talk posts and hope you are amused. The fact is still
that the damn thing actually works as advertised..LOL!
The cost of this testing was not cheap. We chose to do it because we are
sincere in our desire to provide a first rate product. The guarantee we give
on
this product is 100% sarifaction or your money is refunded less our
shipping..So you risk less than 25 bucks to try one...To this date, 486
units
in the field with no returns and no complaints ..NOT EVEN ONE....
That to me is the greatest endorsement..Satified clients.
Most of the detractors we have spoken with have never used a cage of any
design
and certainly not ours. We also have found they are too cheap to take our
challenge and try one even if we agree to pay shipping back. They basically
have their opinion..And that is "if I can't afford it it must not be any
good".
With our warranty there is no risk to try it! Now would we do that if we had
no
confidence in our products. I put my money where my mouth is daily. HOW
ABOUT
YOU! Or are you a person who buys a $3000.00 radio to use as $20 dipole for
an
antenna and then bitch because the rig isn't hearing as good as your
neighbors.
</quote>
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