Francis Amazer Patent info.

[bob85]

If the wire was so hard to cut maybe they used copper plated steel,
I doubt trimming 1/4" would make much difference especially when there are 2 more uncut conductors in there,

you are remembering the amazer tri-quad that one of the freecells posted pics and claims for, I have not been on their website for years.

I always fancied owning an amazer for the collection ever since I heard of them on the US forums,

Like DB I have my doubts about the validity of the Francis patent claims,
they talk about 1/4waves having a low impedance @ resonance, and claim a more efficient match to 52ohm coax than prior art 1/4waves,

give graphs of the response of different length or diameter wires which I take as showing the resonant point of each wire,

I can see multiple wires having a broader vswr bandwidth than a single wire but I can't get my head around how you make a resonant 1/4wave have a 50ohm feedpoint @ resonance when mounted on a car roof, nor have i ever seen a 1/4wave cb antenna anywhere near 15ohms @ resonance,

if its not a resonant antenna but only one that presents a good match then why talk about resonance in the patent,
you can cut most 1/4waves to give a good match on a vswr meter but they won't be resonant.

Im starting to think the patent office will or would back in the day allow you to make all kinds of claims.

 

[Marconi]

Like DB I have my doubts about the validity of the Francis patent claims,
they talk about 1/4waves having a low impedance @ resonance, and claim a more efficient match to 52ohm coax than prior art 1/4waves,

It's OK to have doubts about the ideas presented in Patents. IMO, they are basically just legal descriptions of the ideas of men...set out to defend the idea in court if necessary. I don't think the UPO makes judgments on the merits of the ideas.

give graphs of the response of different length or diameter wires which I take as showing the resonant point of each wire,

I think the Patent intended the graphs to demonstrate in an image...how the idea of broadbanding results applied to their design, nothing more.

I can see multiple wires having a broader vswr bandwidth than a single wire but I can't get my head around how you make a resonant 1/4wave have a 50ohm feedpoint @ resonance when mounted on a car roof, nor have i ever seen a 1/4wave cb antenna anywhere near 15ohms @ resonance,

Bob, I don't see where the Patent claims to make a 50 ohm match, but at column 2, lines 1-4, they do claim their design does provide a more advantageous impedance match. So IMO, it could be argued that it means...concerning the bandwidth improvement.

if its not a resonant antenna but only one that presents a good match then why talk about resonance in the patent,
you can cut most 1/4waves to give a good match on a vswr meter but they won't be resonant.

I have heard many complaints about various vertical CB and mobile antennas over the years. I don't think I have ever heard or read a bad review on any of the original Francis antennas. Most are like JJ posts in the beginning of this thread. But maybe you're right, the only thing we really saw was just a good match and didn't know the difference. That said, long ago I would have argued the antenna just worked better, and I simply expected a good match.

For me, back in those days, I was not looking for understanding of how the Francis worked or the bandwidth, it was just how well it worked on air. That is what I remember.

I looked thru my Antenna Work Sheet files and I found two reports where I used a Francis as the radiator on top of my Marconi *X groundplane, using an A99 hub and 4 x 102" inch slanted down whips as radials.

I did not find the Francis showing a better match than the 102" inch whip, and the bandwidth was not noticeably better either.

I also did some antenna comparisons with the Francis at the time, and it performed very well compared to my Gain Master and Sigma 4.

Im starting to think the patent office will or would back in the day allow you to make all kinds of claims.

As noted above...I don't believe the UPO makes judgments on merit.

Below are the 2 Antenna Work Sheets noted above. They are done with pencils and the print doesn't hold up well. The PDF file allows you to zoom in on a document to see better...see top of page for this zoom feature.

 

[gamegetter]

from reading the francis amazer patent and another discussion we had on the astro plane antenna, my thoughts are that this antenna is electrically a 1/4 wave while using their 3 or more wire wound system to improve the match. whether the performance of an electrical 1/4 wave antenna is less than the performance of an actual length 1/4 wave with worse match, i do not know.

one thing is certain, francis was playing with this in an attempt to either sell more antennas, or perhaps they actually felt they were improving the energy transfer through the system.

with out the data to show it though, it will be hard to decide.

 

[unit_399]

one thing is certain, francis was playing with this in an attempt to either sell more antennas, or perhaps they actually felt they were improving the energy transfer through the system.

with out the data to show it though, it will be hard to decide.

There might not be any real "proof" to back up Francis's claims, but I know that the Amazer was the best all -around mobile antenna I have ever run. If I was standing still in my mobile, the steel whip was slightly better, but when driving the wind resistance bent it back so much that it adversely affected both xmit and recv. Plus I had to be cleaning it all the time to remove the corrosion and oxidation build-up that affected performance too. Even at high speeds the stiffer Amazer hardly bent back, and the encapsulated wires in the Amazer never required cleaning. The larger surface area of the steel whip captured more receive signal, and was more efficient in transmit, but the three wires in the Amazer added additional surface area so that its performance almost equaled that of the whip.

The only real drawback in mobile operation was its height. Low hanging branches and underpasses would beat it to death. I made a replacement tip out of LEXAN polycarbonate rod that provided protection and never lost an antenna after that.

I wish I had one to run on my mobile here.

- 399