R: [TowerTalk] Re: Welcome to towertalk
K7GCO@aol.com
K7GCO@aol.com
Thu, 28 Oct 1999 04:46:34 EDT
Several has asked about a 5 band 2 element quad design with individually
driven elements using a coax switch at the tower. I actually added 6M also.
I tested the design where the DE's are tied together.
< In Eznec on 20, 18, 15, 12 & 10M I have 5 clean (improved) patterns with a
5 band 2 element quad of tapered spacing and individual driven elements. I
even added 6M and you won't believe what happened to it. There is very very
little RF on the other off band DE's and reflectors.
Not so with all DE's tied together which saves the customer money but
destroys the pattern. On 10M the free space vertical pattern is tipped down
about 35 degrees due to the unbalanced currents in the 18, 15 & 12M DE. On
10M, the 20M DE has a high level of current in it as does the reflector. I
call CQ DX and DX stations call me from all directions around the quad. Not
so with individually driven elements. NOTE! So far every antenna I've
modeled in Eznec has checked out exactly for patterns good and bad and even
to the ohm. Putting a 6 band 2 element quad with tapered spacing in a
computer is a big job also.
I also modeled a 10M 3 element yagi (.15Ref- .2Dir) on a 12' boom
tuned for max gain. It had 8 dB F/B and narrow bandwidth as expected (I have
a simple way to widen it) had 6 ohms in the center of the DE and it was
indeed 6 ohms. I fed it where it was 50 ohms with a sneaky feed system not
used by any manufacturer. There was no RF Spill-Over on to the mast and coax
shield either due to unbalanced feed. There is a simple way to balance it
perfectly. The director is 1" longer than the DE. I get great reports on it
and am building one for 12M right now. 12M is great now. So I have great
faith in Eznec. It does wonders if properly used.
I'm moving to my home town in SD and have a nice place 4 miles out if
town with very high ground conductivity and no power lines for a mile. I'm
retired from Boeing as a QA engineer. I got my old zero call back
(WoLMB-Lice, Mice & Bedbugs) as a Club Station (SD Antenna Club) so I can
keep my K7GCO call. It should be a low noise area. I'm 2/3rds there now and
have put aside most of my antenna projects until this winter. I have a lathe
and mill, I can build anything in a very short period of time, a big supply
of aluminum accumulated over 60 years. However I switching to all quads. My
aluminum pile is worth a fortune. I have proved in Eznec and on the air I
can do more with a Quad of half the boom length than a Yagi. That
performance and $ factor gets bigger as the band gets lower.
A 5 band 2 element Quad (I even added 6M) with tapered spacing and
individually DE's like Antenna Mart makes is the All Time Best Buy in
Antennas. With a moderate height of 50',' a moderate tower and rotator, one
coax to a remote coax switch at the quad like Antenna Mart makes, you get
great performance not matched by any other antenna of similar size (and even
bigger). You get the Most Performance/Band /dB/$ for the least hardware and
head aches of any configuration that exists on this earth at this time. I
also got improved F/B. I didn't lose anything multibanding, I actually
gained. Not so with yagi's. I'm adding a variable capacitors in the
reflectors on a common shaft driven by a selsyn at the mast. I can
compensate for any sight or even software variables with the tuned Ref. as I
can peak it at best F/B or gain in seconds. In fact I don't even really need
to model it in Eznec.
I've read every antenna book, article, corresponded with, talked in
person, on the phone and on the air to antenna hams all over, literally tried
everything since 1936 and run all kinds of comparisons. I've given over 450
talks at conventions and clubs on HR, Audio, Power Supplies, Guns and
Photography since 1945. I get lots of letters-on and on. If there is a
better configuration at less cost and headaches, someone tell me what it is.
It was one of the most extensive and costly research programs I've ever
conducted. This 5 band quad (actually 6 bands) will take care of 95% of the
average hams needs on these 6 bands (20-6M) and is easy to install by one
person. It doesn't deteriorate in performance with enameled or insulated
wire and a soldered connection. Yagi Joints corrode with Aluminum Oxide
which I've regularly cleaned. I call it Alumitoid Yagititus! To beat it you
need six 75-100' towers with mono-banders of 4 or more elements, 5 acres of
land (not available to most)(XYL problems) and $30,000+ money (not available
to most). That translates to about 30-40 times more $$$ and hours of
maintenance. You need access to a crane and or the ability to climb and
install. I can still do it at 69 but would rather not. The headaches are
only tolerable for the Big DXers. After 63 years I feel I have found what I
have been looking for all this time. I just want to sit and work DX with
antennas I don't feel I have to or can improve anymore. It consistently
beats bigger systems which is fun to do. I have some improvements I've come
up with that are being used. I also have a novel feed system with no RF
Spill-Over that matches 1:1 on all bands and configurations. No TVI on 6M
with this feed system either.
The difference in Gain between max F/B and the max Gain setting is
small and not really noticeable line of sight but is on DX (sharper vertical
pattern). Being able to reduce the back QRM is very desirable. One
advantage of low F/B on the max gain setting is that is tends to clear the
frequency on the back on xmit and switching to max F/B on receive improves it
even more hi.
I will have mono-band quads of 3 and more elements for comparisons at
the same height. Tuning 3 element quads for max-gain does big things.
I got carried away here but my results are firm. I was hoping to find
someone with similar results or interests. Opinions are welcome but I prefer
actual results. I have no bugs in the software as someone suggested that I
have been able to find so far. Do better testing or use Black Flag.
K7GCO Ken Glanzer
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