There are those who claim that "quads don't scale pattern wise like
yagi's do and have to be retuned." Careful comparison can prove this and I
intend to do it. Yagi's are hard to scale physically as brass model
airplane
tubing diameter steps are too wide compared to the copper wire diameter
steps. Has anyone observed that quads don't scale well as the frequency
difference increases in a controlled experiment?
In the computer they scale, I used a function in Eznec (FRr) to scale
an antenna from 24.95 to 146 MHz or a .1709 reduction in spacing and length.
I had to increase the FR to 155 MHz to get the same pattern. Then I
remembered it doesn't scale the conductor size. So I used the same scale
factor to reduce the #12 wire and it ended up .014" which sounded right.
This time I had to use a FR of 165 MHz. Wait a minute. I had the units in
WL and it was a very large diameter. When I changed the wire diameter to
.014"--Presto! At 146 MHz I get exactly the same pattern as on 12M. So it
scales in Eznec. I have proved that yagi's do scale in Eznec and in actual
practice so I expect quads to scale. The only thing that doesn't scale is
conductivity which can affect the Q of a parasitic element which can affect
the gain.
I'm going to be obtaining all kinds of fiberglass rods and selling off
some of my aluminum tubing. I plan to scale my quad designs at 100 MHz and
use horizontally polarized FM stations as RF sources which are on 24 hours
a day
in flat country in SD. I'll use an FM receiver with an S meter for my FS
meter. I also have a TV/FM FS meter that is ideal for what I want to do. If
the 100 MHz pattern checks out with the Computer software pattern, I'll
then
scale it on 10 M and lower.
One beauty of using the FM BC band as RF sources is that it's wide
enough to
check it's F/B over 88 to 106 MHz. I'll have permanent reference quads up
at the
same height also to compare gain with. The copper wire elements will be
soldered
and there will be no electrical deterioration of the reference. I'll do
some FM DXing
also. Quads are very easy to model to any frequency for spacing, length
and wire
diameter as there are many available diameters of copper wire for easy
scaling and
the ability to end up with say #12 on the desired band. There is a Channel
2 TV
station in SD 90 miles from me that would also be an ideal RF source for
the first
test.
A quads design has been limited to square or diamond. There are many
other configurations I have used that are highly beneficial. No one else
has
apparently done this or someone would have published something. The area
of
even further quad improvement has only been scratched.
There are countless examples of advanced or improved products taking a
long
time to really catch on. Mentalities just couldn't grasp the significance
of the
advanced RF or any design. Quad and yagi sales and performance have been
crippled by many poor mechanical and feedpoint designs of manufacturers who
used all kinds of compromises to cut costs and appeal to cheap skate hams.
There is a special place in hell for these manufacturers and the cheap
skates who
buy this stuff who ruin the market for everyone else. I even wasted my
money on
one also when I knew it was bad instinctively, in Eznec and then on the air
just to
prove it to myself I guess and be able to speak with authority on my
observations.
On 20M I'd call CQDX on Europe and a rare China station came back--off
the
side. I'd call CQDX on JA and a LU comes back. I was stronger when I
pointed
it on them. Contact after contact was like this. The Mfg. claimed "I got
them the
long way around." Ho Ho Ho It was hard to peak a signal even with a fast
rotator.
I used to tell students that if they develop or improve a product,
to
limit the improvement. If too advanced, the educational program will take
too long to catch on, will be too costly. Years later after your patent
has
run out, someone else will steal and claim the idea after you bankrupted
yourself
trying to promote it. A patent is only a license to sue at your expense
when
it is in force. Make only small improvements they can understand and you
can
profit from the sales each time. A quad is a huge improvement in many
ways,
easy for most anyone too see and hear but the wise ones have trouble seeing
it. I sell some "Yagi Tranquilizers" to yagi users who are constantly
frustrated at being aced out by quad users. I sell "RF Antenna Wax" to
yagi
users also. It needs all the help it can get. Would you believe "it
speeds
up the RF Electrons so fast they get there just before they start"?
Early Quad designs of mfgs. and in ham articles were susceptible to
Ice loading. A DXer wrote an article on DX Antennas and left out quads. I
wrote him and asked why? He said "in the NE we have too much ice loading."
Here poor mechanical design resulted in his leaving the quad out of the
comparisons and technically invalidated the whole article. Totally Absurd!
I told him to take a look at Antenna Marts Mechanical and Feedpoint Designs.
K7GCO Ken Glanzer
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