Let's have a look...

[trees]

Inside a Francis antenna....

Interesting, I believe that's enameled wire. And, it's wound with two wires sharing a common feed point, but electrically isolated from each other. I wonder if this was the inspiration for the Van Ordt quad wrap?

I know it inspired me to make my own version.

 

[Sarasota Slim]

Now, is this a Francis antenna, as they are currently manufactured, as a company owned and operated by DAS?

Or, is this an older Francis antenna?

 

[trees]

Now, is this a Francis antenna, as they are currently manufactured, as a company owned and operated by DAS?

Or, is this an older Francis antenna?

I'm not sure as to the actual age of the antenna, but I don't think its vintage. I think it's probably two, maybe three years old. I don't know that there's much difference between then, and now. The construction seemed solid, the inner core was well formed, and the wire turns were even and consistent. What I didn't like was how fine the diameter of the wire is, and how many tightly spaced windings there are. It was wound top to bottom, the entire length, with that tight spacing. Antenna theory holds that to be a lossy design. I attempted to put a lot of copper, widely spaced turns, on the transmitting section, that's 12 gauge finely stranded braided wire running in parallel. It shares a common feedpoint, and terminates at the loading inductor, but is isolated from the enameled wire for about 4'. I finished it with a heavy duty polyolefin covering. I made a pair of them, but haven't had a chance yet to tune them up and try em out...

 

[Sarasota Slim]

I'm not sure as to the actual age of the antenna, but I don't think its vintage. I think it's probably two, maybe three years old.

Ok; then I reckon it's a DAS product.

I don't know that it makes a difference; or if it does, if it's a meaningful difference. I was just curious.

I'd actually be interested in seeing a comparison of DAS products, as currently made, with the companies products from before they were bought by DAS. Such as original Francis vs DAS Francis, original K40 vs DAS K40, etc. How have the quality of workmanship and materials changed since DAS bought them?

But, that strays from topic, and I don't want to hijack your thread.

 

[trees]

Ok; then I reckon it's a DAS product.

I don't know that it makes a difference; or if it does, if it's a meaningful difference. I was just curious.

I'd actually be interested in seeing a comparison of DAS products, as currently made, with the companies products from before they were bought by DAS. Such as original Francis vs DAS Francis, original K40 vs DAS K40, etc. How have the quality of workmanship and materials changed since DAS bought them?

But, that strays from topic, and I don't want to hijack your thread.

As far as Francis antennas go, they look to be pretty much the same today, as those of old. I had never broken one open to look inside... I made sure to wear eye protection and heavy gloves/clothing. Fiberglass is nasty stuff when it's splintering apart.

 

[Marconi]

Tree, I'm not sure this is what you are looking for, but the Francis patent in this link fransis 8 ft moble antenna will show their antenna is not similar to your helix wound coil antenna.

 

[trees]

Tree, I'm not sure this is what you are looking for, but the Francis patent in this link fransis 8 ft moble antenna will show their antenna is not similar to your helix wound coil antenna.

Hi. The antenna in photo 1 is a Francis antenna, but it's neither the WD, or Amazer. Those Antenna's were very long, I believe. (Just a little shorter than 1/4?) I also think that they used a form of capacitive loading, and the length, combined with capacitive loading, helped the efficiency and bandwidth.

My antenna is not an attempt to copy either of those, but rather, an attempt to improve on the concept of the linear loading, helical design. My thoughts were this, to increase the power handling, introduce some capacitive coupling, provide a large signal capture area, and to provide a large current carrying section that extended two thirds the overall length, allowing the current to efficiently radiate along a large portion of the shortened element. The inductor, being at the top, can be a finer diameter, without affecting the flow of current coming up from the base, as the current travels on the larger diameter wire that parallels the overall length of enameled wire....

As the wave travels from the feed point, current decreases as voltage increases.

I value your thoughts on this, thank you.

 

[trees]

Photo of the Francis base. (I think this is/was a 4.5 foot Hot Rod.

 

[bob85]

Francis had patents on straight and helical multi conductor antennas like the one shown above.

 

[Marconi]

Thanks to you both, I've learned something new today.

I was not aware that Francis also made helical wound antennas too.

Bob do you have a link or a Patent number for their helical wound antenna?

 

[Marconi]

Bob, I find that the brand name Francis is still in production by the company in the link below...just like Sarasota Slim said in his earlier post above:

http://www.dasinc.com/contact.cfm#branded.cfm

This is a current day company and apparently owns several name brands from the CB world. A sign of the times no doubt.

I said in my initial post above that I wasn't sure if I was on point with Trees comments. I came to this thread via an alert that Bob85 had made a post. So, I checked it out.

Above Bob's post I saw Tress post but I did not read the rest of the thread to see what was really going on. Sorry!

Now I understand Trees was talking about a modern Francis antenna design, so I was not on point with his comments.

Bob. I would still like to look at the Patent on the Francis helical wound design.

 

[Sarasota Slim]

The thing with DAS, is that the primary function of the company is to stock travel centers. That's why I was wondering, above, about the quality of product before and after DAS bought the company. I have noticed that, for example, folks that have used older Turner RoadKing mics, tend to find them superior in performance and build quality, than the modern DAS RoadKing. On the other hand, I saw something the other day, that indicated that Wilson branded coax was actually Belden with Amphenol connectors. (This makes me wonder about the K40 and Astatic branded coax)

I've theorized that bean counters run the DAS show, and that there is a high possibility that cost of production takes precedent over any sort of quality. Thus, I find myself a little distrustful of DAS brands.

 

[Marconi]

Slim, I think you are right. Like I said above...A sign of the time no doubt.

 

[Sarasota Slim]

...A sign of the time no doubt.

Indeed, sadly.

 

[trees]

Installed and tuned up the antennas I altered with heavy copper stranded wire. Been using them for a few weeks now, and they perform better than any antenna I've ever used.