"John S" wrote in message ...

On 11/7/2014 12:58 PM, wrote:
wrote:

snip

The only downside to this antenna is that it is extremely narrow
banded, only about a kHz or so.

snip

I realized I should expand on that.

With all 5 inductors the same value the 5:1 bandwidth is about 500 Hz.

By staggering the values of the inductors in the four legs the bandwidth
can be improved by a little bit.

The best I could accomplish was about 1 Khz by making the leg values
.96, .98, 1.02, and 1.04 times the central leg value.

Going beyond a step factor of .02 made little difference in the bandwidth
and the resonant frequency SWR started to increase.

# Okay, but the starting target was to be able to feed a short antenna
# with good efficiency and I think you hit that target. I know you want to
# keep it as practical as possible, but I am impressed with your results.

I agree. I like the approach.

Anyone ready to tackle a fractal design

On 11/8/2014 10:57 AM, Wayne wrote:


"John S" wrote in message ...
On 11/7/2014 12:58 PM, wrote:
wrote:

snip

The only downside to this antenna is that it is extremely narrow
banded, only about a kHz or so.

snip

I realized I should expand on that.

With all 5 inductors the same value the 5:1 bandwidth is about 500 Hz.

By staggering the values of the inductors in the four legs the bandwidth
can be improved by a little bit.

The best I could accomplish was about 1 Khz by making the leg values
.96, .98, 1.02, and 1.04 times the central leg value.

Going beyond a step factor of .02 made little difference in the bandwidth
and the resonant frequency SWR started to increase.

# Okay, but the starting target was to be able to feed a short antenna #
with good efficiency and I think you hit that target. I know you want to
# keep it as practical as possible, but I am impressed with your results.

I agree. I like the approach.

Anyone ready to tackle a fractal design


I have no idea how to approach that, but I'm willing to read your posts
on it. Start by assuming zero knowledge for me.

On 11/8/2014 10:45 AM, wrote:
John S wrote:
On 11/7/2014 12:58 PM, wrote:
wrote:

snip

The only downside to this antenna is that it is extremely narrow
banded, only about a kHz or so.

snip

I realized I should expand on that.

With all 5 inductors the same value the 5:1 bandwidth is about 500 Hz.

By staggering the values of the inductors in the four legs the bandwidth
can be improved by a little bit.

The best I could accomplish was about 1 Khz by making the leg values
.96, .98, 1.02, and 1.04 times the central leg value.

Going beyond a step factor of .02 made little difference in the bandwidth
and the resonant frequency SWR started to increase.

Okay, but the starting target was to be able to feed a short antenna
with good efficiency and I think you hit that target. I know you want to
keep it as practical as possible, but I am impressed with your results.

Thanks.

The whole point of the exercise was to show there are way to overcome
the generally low impedance of short antennas.

Exactly! It was a challenge which has been shown to be surmountable by
design. Feed losses become less of a burden this way.

Do you think your results could be practical? Could ground resistance be
used to widen the BW? I know, there are losses. But, maybe worth it?

What do you think?

On Saturday, November 8, 2014 11:15:33 AM UTC-6, John S wrote:
On 11/8/2014 10:57 AM, Wayne wrote:


"John S" wrote in message ...
On 11/7/2014 12:58 PM, wrote:
wrote:

snip

The only downside to this antenna is that it is extremely narrow
banded, only about a kHz or so.

snip

I realized I should expand on that.

With all 5 inductors the same value the 5:1 bandwidth is about 500 Hz.

By staggering the values of the inductors in the four legs the bandwidth
can be improved by a little bit.

The best I could accomplish was about 1 Khz by making the leg values
.96, .98, 1.02, and 1.04 times the central leg value.

Going beyond a step factor of .02 made little difference in the bandwidth
and the resonant frequency SWR started to increase.

# Okay, but the starting target was to be able to feed a short antenna #
with good efficiency and I think you hit that target. I know you want to
# keep it as practical as possible, but I am impressed with your results.

I agree. I like the approach.

Anyone ready to tackle a fractal design


And they say I like to stir it... lol


I have no idea how to approach that, but I'm willing to read your posts
on it. Start by assuming zero knowledge for me.

We thrashed that around quite a bit many moons ago.
Richard Clark in particular did quite a bit of pondering and puter
simulation on the subject.
http://www.qsl.net/kb7qhc/antenna/fractal/

I think the most chortle inducing moment was when a totally random
design outdid one that the guru of all things fractal spit out using
his highly self touted puter optimizations.

I came to the conclusion that fractal antennas were nothing more
than linear loading using pretty design schemes.
Often no real advantage to a random design drawn with the eyes closed,
but hey, if one can attract gov grants, contracts and such, using
advanced forms of bafflegab to lure in the gullible, one can overlook
such things while laughing all the way to the bank.

Actually, I consider any symmetrical antenna design to be a fractal
of sorts.. Even a dipole as the simplest form.

John S wrote:
On 11/8/2014 10:45 AM, wrote:
John S wrote:
On 11/7/2014 12:58 PM, wrote:
wrote:

snip

The only downside to this antenna is that it is extremely narrow
banded, only about a kHz or so.

snip

I realized I should expand on that.

With all 5 inductors the same value the 5:1 bandwidth is about 500 Hz.

By staggering the values of the inductors in the four legs the bandwidth
can be improved by a little bit.

The best I could accomplish was about 1 Khz by making the leg values
.96, .98, 1.02, and 1.04 times the central leg value.

Going beyond a step factor of .02 made little difference in the bandwidth
and the resonant frequency SWR started to increase.

Okay, but the starting target was to be able to feed a short antenna
with good efficiency and I think you hit that target. I know you want to
keep it as practical as possible, but I am impressed with your results.

Thanks.

The whole point of the exercise was to show there are way to overcome
the generally low impedance of short antennas.

Exactly! It was a challenge which has been shown to be surmountable by
design. Feed losses become less of a burden this way.

Do you think your results could be practical? Could ground resistance be
used to widen the BW? I know, there are losses. But, maybe worth it?

What do you think?

I think if the goal is a practical antenna, the starting point should be
how high can you practically go keeping in mind that a 1/4 wave 160M is
on the order of 130 feet and in general the higher the greater the
bandwidth and the less you have to be concerned with minimizing losses.

In my urban lot, anything over about 30 feet becomes a problem.

I do have a 33 foot tall vertical in the back yard with an autotuner
at the base. It started out as just a 40M vertical.

With the addition of the autotuner, it will tune and load 160 through
6 M. The performance on 6M is horrible as it is a cloud warmer at
that frequency, but most of the other bands are OK or better.

The 160 and 80 performance was poor, which I attibuted to losses in
the tuner, so I put in a relay controlled high Q tapped coil to take
some of the burden off of the autotuner on those bands. That helped
quite a bit.

I have been thinking about using the folded monopole technique to
further improve things.

That would require some more relays to switch the folded parts into
the main radiator, essentially making it a fat radiator on other bands.

The biggest issue is mechanical so until I figure out that part, I
have left that project on the back burner for now.


--
Jim Pennino

"John S" wrote in message ...

On 11/8/2014 10:57 AM, Wayne wrote:


"John S" wrote in message ...
On 11/7/2014 12:58 PM, wrote:
wrote:

snip

The only downside to this antenna is that it is extremely narrow
banded, only about a kHz or so.

snip

I realized I should expand on that.

With all 5 inductors the same value the 5:1 bandwidth is about 500 Hz.

By staggering the values of the inductors in the four legs the bandwidth
can be improved by a little bit.

The best I could accomplish was about 1 Khz by making the leg values
.96, .98, 1.02, and 1.04 times the central leg value.

Going beyond a step factor of .02 made little difference in the bandwidth
and the resonant frequency SWR started to increase.

# Okay, but the starting target was to be able to feed a short antenna #
with good efficiency and I think you hit that target. I know you want to
# keep it as practical as possible, but I am impressed with your results.

I agree. I like the approach.

Anyone ready to tackle a fractal design


# I have no idea how to approach that, but I'm willing to read your posts
# on it. Start by assuming zero knowledge for me.

That comment was made in jest, and nm5k picked up on it with his response.

Some years back there were the Great Fractal Wars (TM) on this group. Some
of the recent comments reminded me of those days.

In summary, one poster was pushing his design of a fractal antenna and it
took hundreds (if not thousands) of posts to get him to nail him down on the
design. It didn't seem to have any particular advantage over other
antennas, and had a more complex construction.

Wayne wrote:


"John S" wrote in message ...

On 11/8/2014 10:57 AM, Wayne wrote:


"John S" wrote in message ...
On 11/7/2014 12:58 PM, wrote:
wrote:

snip

The only downside to this antenna is that it is extremely narrow
banded, only about a kHz or so.

snip

I realized I should expand on that.

With all 5 inductors the same value the 5:1 bandwidth is about 500 Hz.

By staggering the values of the inductors in the four legs the bandwidth
can be improved by a little bit.

The best I could accomplish was about 1 Khz by making the leg values
.96, .98, 1.02, and 1.04 times the central leg value.

Going beyond a step factor of .02 made little difference in the bandwidth
and the resonant frequency SWR started to increase.

# Okay, but the starting target was to be able to feed a short antenna #
with good efficiency and I think you hit that target. I know you want to
# keep it as practical as possible, but I am impressed with your results.

I agree. I like the approach.

Anyone ready to tackle a fractal design


# I have no idea how to approach that, but I'm willing to read your posts
# on it. Start by assuming zero knowledge for me.

That comment was made in jest, and nm5k picked up on it with his response.

Some years back there were the Great Fractal Wars (TM) on this group. Some
of the recent comments reminded me of those days.

In summary, one poster was pushing his design of a fractal antenna and it
took hundreds (if not thousands) of posts to get him to nail him down on the
design. It didn't seem to have any particular advantage over other
antennas, and had a more complex construction.

He also had some "antennas for hams" on his web site, long taken down,
that he raved about.

Apparently he thought he was the only one with any antenna analysis
capability.



--
Jim Pennino

wrote in message ...

Wayne wrote:


"John S" wrote in message ...

On 11/8/2014 10:57 AM, Wayne wrote:


"John S" wrote in message ...
On 11/7/2014 12:58 PM, wrote:
wrote:

snip

The only downside to this antenna is that it is extremely narrow
banded, only about a kHz or so.

snip

I realized I should expand on that.

With all 5 inductors the same value the 5:1 bandwidth is about 500 Hz.

By staggering the values of the inductors in the four legs the bandwidth
can be improved by a little bit.

The best I could accomplish was about 1 Khz by making the leg values
.96, .98, 1.02, and 1.04 times the central leg value.

Going beyond a step factor of .02 made little difference in the
bandwidth
and the resonant frequency SWR started to increase.

# Okay, but the starting target was to be able to feed a short antenna #
with good efficiency and I think you hit that target. I know you want to
# keep it as practical as possible, but I am impressed with your results.

I agree. I like the approach.

Anyone ready to tackle a fractal design


# I have no idea how to approach that, but I'm willing to read your posts
# on it. Start by assuming zero knowledge for me.

That comment was made in jest, and nm5k picked up on it with his response.

Some years back there were the Great Fractal Wars (TM) on this group.
Some
of the recent comments reminded me of those days.

In summary, one poster was pushing his design of a fractal antenna and it
took hundreds (if not thousands) of posts to get him to nail him down on
the
design. It didn't seem to have any particular advantage over other
antennas, and had a more complex construction.

# He also had some "antennas for hams" on his web site, long taken down,
# that he raved about.

# Apparently he thought he was the only one with any antenna analysis
# capability.

LOL...yeah, one time I took his "fractvert", which required two supports,
and modified it to use one support.
Then I posted the EZNEC results and he got real ****y about it. Good times?

On Saturday, November 8, 2014 3:51:45 PM UTC-6, Wayne wrote:

LOL...yeah, one time I took his "fractvert", which required two supports,
and modified it to use one support.
Then I posted the EZNEC results and he got real ****y about it. Good times?


What was the name of his sidekick? Phil I think it was?
I once had him foaming at the mouth and drooling all over his keyboard.
He was severely bent out of shape because I was heckling the Chipper over
that antenna... chortle I'm a bad man I guess... lol

wrote in message
...

On Saturday, November 8, 2014 3:51:45 PM UTC-6, Wayne wrote:

LOL...yeah, one time I took his "fractvert", which required two supports,
and modified it to use one support.
Then I posted the EZNEC results and he got real ****y about it. Good
times?


What was the name of his sidekick? Phil I think it was?
I once had him foaming at the mouth and drooling all over his keyboard.
He was severely bent out of shape because I was heckling the Chipper over
that antenna... chortle I'm a bad man I guess... lol

Yes, I think it was Phil.

It's amusing to think back on those times, but don't think I'd like to
repeat them