On 3 Jul, 10:17, "Mike Kaliski" wrote:
"art" wrote in message

oups.com... On 17 Jun, 16:13, "Mike Kaliski" wrote:
"John Smith I" wrote in

...





Actually, old news from 3 years ago ...

http://www.eetimes.com/showArticle.j...cleID=21600147

JS

The guy doesn't even seem to realise that height is one of the prime
factors
in optimising propogation, particularly at medium wave frequencies and
vhf.
Building a tall mast costs plenty of money and if commercial radio
stations
could broadcast efficiently from an antenna the size of a bean can, they
would have done it years ago.

This is surely just a couple of coils wound in opposite directions with
capacitive coupling and a capacity top hat to prevent coronal discharge
and
maximise current in the top half of the antenna. Basically a form of top
loaded, inductively wound whip antenna tapped somewhere up from the base
in
order to pick up a 50 ohm matching impedence at the design frequency. I
don't see any new or innovative principles at work here.

Now if he could make it work efficiently on all frequencies with 50 ohms
impedence and with no requirement for further matching or adjustment of
any
sort, I would be impressed. :-)

Mike G0ULI

Mike
The antenna is based on confirmed scientific findings of the masters
and can be proved mathematically as one would expect from such an
antenna.
It is true that what happens to radiation when it is formed is
important
but what is more important is to understand radiation in its formative
stage.
When this is understood then miniturisation comes to the fore that
may
well be more important than the TOA but then even this antenna can be
raised in height. There is a lesson to be learned here. The Yagi was
invented by the Japanese in the early 1920 where America embraced the
invention
and where Japan did not. That same invention proved to be one of
Japans
undoing as they never caught on to the importance possibly by
beurocracy.
This new antenna has been pushed aside by America where I am positive
other Countries are moving fast ahead and now have 3 years lead to
play with.
It is America this time that is complacent. The antenna is there,
the mathematics is there and Maxwells laws are still there, all of
which conform with each other both with this antenna and my Gaussian
antenna but who cares.
Art Unwin KB9MZ.......XG

Art

There is a place for miniaturised antennas, particularly for military
applications where size and weight of the antenna outweigh other
considerations which are important to commercial and amateur users e.g
bandwidth and efficiency.

The yagi has great front to back ratios and makes for a great if slightly
narrow band antenna for UHF TV reception here in the UK. These antennas are
generally sold tuned to cover the local TV frequency channels rather than
the whole of the UHF TV band. A lot of people will need to buy new antennas
when the switch over to digital TV broadcasting takes place as the digital
channels have been arranged to be at the opposite ends of the band to
analogue TV in most areas.

The yagi was probably the first antenna that did not conform to antenna
theory as it was understood at the time it was developed. Small loops and
E-H antennas also appear to defy logic at first glance but careful analysis
of their performance has revealed how they work with higher efficiencies
than previously believed possible.

Unfortunately for some, there is no magic or defiance of the accepted laws
of physics involved in the way they work.

There are still areas which provide fertile areas for experimentation,
particularly at the extremes of the radio frequency spectrum.

Regards

Mike- Hide quoted text -

- Show quoted text -

Interesting that you mentioned efficiency. Radiation in itself is very
efficient
i.e. in the 98% region It is how we use it is where the efficiency
goes down.
But if initial efficiency starts of with 98% and with a superconductor
we
gain two percent it becomes very obvious that loss of efficiency even
if
large is minor when compared to the reduction in size. As far as
narrow bandedness is concerned of the yagi this has little to do with
efficiency
but with what we do with the radiation which by coupling as a method
of
focussing to get a major lobe. True this is an advantage to some but
the
penalty is narrow banded because of compromises that are forced upon
one where
the desirables do not appear in sync with each other. So yes a very
small
antenna may be less efficient but how much does that loss in
efficiency
match up to the advantage in size and where the final shape provides
desirables that are in sync with each other. Amateurs have long
thought that
bigger is better and if it doesn't fall down then it is not big
enough!
All of which is not based on radiation itself but on the basis of
Yagi
technique on how we use that radiation. Times have changed from the
old
days where gain was everything. Miniturization has become so important
as well as equal surrounding coverage that the cell phone has become
an instantaneous replacement for long distance transmission in the
commercial world. As I read in this latest quarterly magazine for the
antenna trade
the biggest hold up today in communications is to design drivers with
low impedance levels such as 5 ohms where this in fact misuses modern
day science.
We now can obtain miniturised design with minimul reduction of
bandwidth and minimul
loss of comparitive efficiency where higher impedance feed is so more
electrically efficient
that it makes low impedance a lost cause. I am quite sure that other
countries are not discarding such logic and thus taking advantage of
the intervening years
for advances in the military field where secrecy can be adhered to.
Well at least for a while.
Best regards
Art Unwin KB9MZ.....XG