Francis Amazer Patent info.

is the Patent for the Francis Amazer and Wheeler Dealer antenna designs. It is an interesting and novel idea to improve match and bandwidth for a 1/4 wave mobile antenna that is shorter than 102" ss whip.

patent:3541567 - Google Patent Search

AudioShockwav said:

I have a couple of these antennas, triple quarter wave, they are well built and i like how they are much stiffer than a SS whip, do not flop around as much as the steel whip does.


73
Jeff

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Hey Jeff. If I can get up enough energy I want to mount my Wheeler Dealer in the top of my Marconi 6x antenna and compare the match and bandwidth with a 102" radiator. See if I can see any of the advantages they describe in the Patent using my analyzer.

W5LZ said:

Where that antenna has a problem is with 'end-effect' (patented or not). Do the test!
- 'Doc

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'Doc, will you please explain what I should look for in order to understand this end effect problem and how it affects this antenna while I'm trying to compare the 102" whip to my Francis.

unit_399 said:

MARCONI -

Back in the late 80s, I went to the CES in Vegas. Francis had a small booth there, and I talked to their engineer at length about their antennas. He told me that the difference between the Wheeler-Dealer and the Amazer was that the three wires in the W-D were all the same length, but that the wires in the gray Amazer were three slightly different lengths. He said that this made the Amazer resonant at three different frequencies, which increased the bandwidth. (?????)

Whatever... the Amazer is the best mobile antenna I have ever run, despite its so-called "end effect" problem.

BTW... the patent info for the Amazer used to be on FREECELL's (sorry to mention that name here Mr. Administrator) website.

-399

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399, that may be exactly the way the design works too.

I seem to recall that the patent described their idea using several schemes. One with three wires, like you describe, each being the same length. I think in that case each wire would necessarily have a different diameter however. Another scheme described used three wires with the same diameter, but with different lengths and this makes sense too.

I think the patent talked about the idea of improving the antenna response and bandwidth, but I'm not sure I understand how that really affects its usefulness. I thought mine worked very good for me at the time, but I can't tell you why.

AudioShockwav said:

Marconi, did you ever do this test?


73
Jeff

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Yes Jeff, I did install my Francis Wheeler Dealer in the top of my Marconi with 4 slanted down 102" radials.

My notes, however, don't show that I did any specific comparison work to a similar install with 102" ss radiator as I promised. Gettin' old.

I do have some analyzer and SWR bandwidth reports that I recorded, but the antenna heights were not the same and there is no indication on which mount the antennas were installed on. So, it looks like I wasn't thinking about such a consideration when I finally got around to doing testing with the Francis some months later.

The reports do, however, show that the Francis, at 31' high, was resonant about 18 channels lower in frequency than the 102" whip at 52' feet. The height for the Francis was about 20' lower as noted. Maybe this height difference made or contributed to this lowering in frequency, but I'm not sure.

I also noticed that the bandwidth for the Francis was actually less that the 102" whip as well, and I am surprised at both results. I would have though things to be the very opposite from my previous thinking back then.

Another thing I noticed in looking over this old record is that the Francis and the 102" whip manifested about the same mismatch on my analyzer, and again that surprises me. I would think the Francis might show a better match for CB. That said however, it is my opinion that the modest matching differences we might expect to see among such CB antennas will not exhibit enough difference in performance for us to tell just using our radios.

While all this testing was going on back then, I was also doing signal reports, but I can't find any notations on the Marconi reports telling me which radiator I was using, so another dead end.

IMO, this style of antenna is very well balanced and the radial cone below the feed point appears to help improve feed line decoupling. This said however, modeling of these type antennas does show that specific heights of the mast and the length of the feed line plays an important role in such destructive radiation, so maybe we can't fully attribute all of this affect to the radial cone design in this particular antenna.

I can't prove it, but these symmetrical features in combination with a 1/2 wave radiator that shows minimal feed line and mast currents could be what provides the very good signal reports I typically see when comparing it against my other antennas.

KF6IRK said:

I still have two Amazers up in the rafters in my garage. I had two of them mounted in a co-linear array, 3" apart on an aluminum plate atop a heavy duty spring and used nylon spacers to keep the antennas exactly 3" apart from top to bottom. Worked very well on the '89 Toyota pick up I had at the time.

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Kapt Irk what color are your Francis whips?