They say they have a patent pending for that... wonder if it's true.
What are the patent regulations, does the patented invention actually
have to work, or can any crazy thing be patented?

In theory, a patented invention must be "useful", "novel", and
"non-obvious". Most would say that "useful" requires that it actually
work, at least to some extent. It used to be the case, long ago, that
you had to actually build at least a working model and be able to
demonstrate that the device worked.

However, in practice, the rules have changed. Many patent claims are
allowed based solely on a description (which must, again in principle,
be sufficiently detailed to allow someone skilled in the art to
reproduce the invention as described) and no working model is ever
presented. It's also clear that many patent examiners are content to
accept the filer's explanation about how and why the invention works,
and that they're sometimes woefully ignorant of the actual state of
the art and of the existence of relevant prior art.

On the other hand, "patent pending" simply means that they've filed.
It doesn't mean that the patent has been issued, or has even been
allowed and is on the way to being issued. It's entirely possible
that most or all of their claims have been, or will be laughed out of
court by the patent examiner.

Even if they do have a valid patent claim in the works, there's
nothing definite to say that their flowery public description about
how their product is supposed to work, corresponds at all closely to
the wording in the patent claims. They might have filed a patent
claim for some narrowly-worded aspect of the design of this specific
product (e.g. a specific size and shape of the ripples), without
trying to claim wider coverage via a "utility" patent and its
description and claims.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

"Dave Platt" wrote in message
...
They say they have a patent pending for that... wonder if it's true.
What are the patent regulations, does the patented invention actually
have to work, or can any crazy thing be patented?

In theory, a patented invention must be "useful", "novel", and
"non-obvious". Most would say that "useful" requires that it actually
work, at least to some extent. It used to be the case, long ago, that
you had to actually build at least a working model and be able to
demonstrate that the device worked.

They say one of the simplest patents ever granted was for the number 1.65.
It was granted to Phillip H. Smith as the optimum diameter ratio for a
coaxial transmission line.

Not often I get to use that bit of trivia.

dtk

In article ,
dt king wrote:

In theory, a patented invention must be "useful", "novel", and
"non-obvious". Most would say that "useful" requires that it actually
work, at least to some extent. It used to be the case, long ago, that
you had to actually build at least a working model and be able to
demonstrate that the device worked.

They say one of the simplest patents ever granted was for the number 1.65.
It was granted to Phillip H. Smith as the optimum diameter ratio for a
coaxial transmission line.

Neat - that's the ratio which gives the lowest loss per weight/cost
of materials given standard (WW II) dielectrics, right?

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Dave Platt wrote:
In article ,
dt king wrote:

In theory, a patented invention must be "useful", "novel", and
"non-obvious". Most would say that "useful" requires that it
actually
work, at least to some extent. It used to be the case, long ago,
that
you had to actually build at least a working model and be able to
demonstrate that the device worked.

They say one of the simplest patents ever granted was for the number
1.65.
It was granted to Phillip H. Smith as the optimum diameter ratio for
a
coaxial transmission line.

Neat - that's the ratio which gives the lowest loss per weight/cost
of materials given standard (WW II) dielectrics, right?


It is a common mis-conception, but dielectric loss is not significant
for most coax cables at frequencies below a few GHz. The copper losses
are by far dominant. Teflon dielectric reduces cable loss because it
allows the use of a thicker center conductor which reduces copper loss.

http://www.microwaves101.com/encyclopedia/Coaxloss.cfm


Mark

In article .com,
Mark wrote:

Neat - that's the ratio which gives the lowest loss per weight/cost
of materials given standard (WW II) dielectrics, right?


It is a common mis-conception, but dielectric loss is not significant
for most coax cables at frequencies below a few GHz. The copper losses
are by far dominant. Teflon dielectric reduces cable loss because it
allows the use of a thicker center conductor which reduces copper loss.

http://www.microwaves101.com/encyclopedia/Coaxloss.cfm

Understood! However, the decreased losses come at a significant cost
disadvantage - the Teflon dielectric is more expensive, and the
thicker center conductor uses more metal and is thus both heavier and
more expensive.

My recollection is that the 1.56 diameter ratio (and a 52-ohm
characteristic impedance) were selected because this placed the cable
design in a "sweet spot" in the "RF loss per dollar spent making the
cables" curve. Again if I recall properly (possibly not) this
occurred during World War II, when the wartime economy required
producing the military equipment as cost-efficiently as possible.

Lower losses are certainly possible, using different characteristic
impedances and different dielectrics, but (if I understand the story
right) the materials and prices available back in the era in question
were such that the lower-loss coaxial cable designs were restricted in
their application.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

http://www.rfcafe.com/references/ele...of_50_ohms.htm



There are probably lots of stories about how 50 Ohms came to be. The
one I am most familiar goes like this. In the early days of microwaves
- around World War II, impedances were chosen depending on the
application. For maximum power handling, somewhere between 30 and 44
Ohms was used. On the other hand, lowest attenuation for an air filled
line was around 93 Ohms. In those days, there were no flexible cables,
at least for higher frequencies, only rigid tubes with air dielectric.
Semi-rigid cable came about in the early 50's, while real microwave
flex cable was approximately 10 years later.


Somewhere along the way it was decided to standardize on a given
impedance so that economy and convenience could be brought into the
equation. In the US, 50 Ohms was chosen as a compromise. There was a
group known as JAN, which stood for Joint Army and Navy who took on
these matters. They later became DESC, for Defense Electronic Supply
Center, where the MIL specs evolved. Europe chose 60 Ohms. In reality,
in the US, since most of the "tubes" were actually existing materials
consisting of standard rods and water pipes, 51.5 Ohms was quite
common. It was amazing to see and use adapter/converters to go from 50
to 51.5 Ohms. Eventually, 50 won out, and special tubing was created
(or maybe the plumbers allowed their pipes to change dimension
slightly).


Further along, the Europeans were forced to change because of the
influence of companies such as Hewlett-Packard which dominated the
world scene. 75 Ohms is the telecommunications standard, because in a
dielectric filled line, somewhere around 77 Ohms gives the lowest loss.
(Cable TV) 93 Ohms is still used for short runs such as the connection
between computers and their monitors because of low capacitance per
foot which would reduce the loading on circuits and allow longer cable
runs.


Volume 9 of the MIT Rad Lab Series has some greater details of this for
those interested. It has been reprinted by Artech House and is
available.

C'mon man, what are you doing? There's no snake-oil whatsoever in
anything you've just written!

On 2005-03-05 12:02:22 +1100, said:

http://www.rfcafe.com/references/ele...of_50_ohms.htm



There are probably lots of stories about how 50 Ohms came to be. The
one I am most familiar goes like this. In the early days of microwaves
- around World War II, impedances were chosen depending on the
application. For maximum power handling, somewhere between 30 and 44
Ohms was used. On the other hand, lowest attenuation for an air filled
line was around 93 Ohms. In those days, there were no flexible cables,
at least for higher frequencies, only rigid tubes with air dielectric.
Semi-rigid cable came about in the early 50's, while real microwave
flex cable was approximately 10 years later.


Somewhere along the way it was decided to standardize on a given
impedance so that economy and convenience could be brought into the
equation. In the US, 50 Ohms was chosen as a compromise. There was a
group known as JAN, which stood for Joint Army and Navy who took on
these matters. They later became DESC, for Defense Electronic Supply
Center, where the MIL specs evolved. Europe chose 60 Ohms. In reality,
in the US, since most of the "tubes" were actually existing materials
consisting of standard rods and water pipes, 51.5 Ohms was quite
common. It was amazing to see and use adapter/converters to go from 50
to 51.5 Ohms. Eventually, 50 won out, and special tubing was created
(or maybe the plumbers allowed their pipes to change dimension
slightly).


Further along, the Europeans were forced to change because of the
influence of companies such as Hewlett-Packard which dominated the
world scene. 75 Ohms is the telecommunications standard, because in a
dielectric filled line, somewhere around 77 Ohms gives the lowest loss.
(Cable TV) 93 Ohms is still used for short runs such as the connection
between computers and their monitors because of low capacitance per
foot which would reduce the loading on circuits and allow longer cable
runs.


Volume 9 of the MIT Rad Lab Series has some greater details of this for
those interested. It has been reprinted by Artech House and is
available.