Hello All

Well after all the comments made and doing some research on the G5RV( I
guess it has it place) I have decide to try something new and hopefully
better.Here it is, the Mystery Antenna,I had all the parts at home, so it
did not cost any money at this point.
Built it last night took about 1.5 hrs to build,including making my own
center insulators and end insulators.Here is the link to the site,I am sure
allot of you in this group know about it and looking forward to your
comments.Will let you all know how it works,and some of the readings I get
from it.
http://w5gi.com/mysteryantenna.htm

thanx all
Howard
VE4ISP
ps. thanx to all that commented on my G5RV post

On 2008-09-29, Howard Kowall wrote:
Hello All

Well after all the comments made and doing some research on the G5RV( I
guess it has it place) I have decide to try something new and hopefully
better.Here it is, the Mystery Antenna,I had all the parts at home, so it

I built a Mystery Antenna a few years ago just to see how it performed.
Since then, John has changed his explanation a bit, but it is supposed to
have a better pattern for its designed frequency, ala 20m, than the g5rv. Of
course you can design it for whatever frequency you wish. I use mine for an
all band portable antenna and it seems to work well.

I ended the parallel line in a pl-259. To that I attach, with a barrel
connector, a ferrite bead balun (W2DU style) and then the coax to the tuner
to prevent any common mode from coming back down the line. We use it at ham
field day each year for the GOTA area.

I will not claim any particular advantage over, say, a dipole fed with
ladder line to a tuner and will not quote reports, which are at best nebulus
anyway, but it was fun to build and does work fine.

Incidentally, the cw operator at field day put together the D3 (the 1.5
wavelength ant) on John's W5GI site, tuned for the 40m cw freqs and it
worked very well. Of course that requires a bit more real estate.

73 ...Edwin, KD5ZLB
--
__________________________________________________ __________
"Once you have flown, you will walk the earth with your eyes
turned skyward, for there you have been, there you long to
return."-da Vinci http://bellsouthpwp2.net/e/d/edwinljohnson

Howard Kowall wrote:

...
comments.Will let you all know how it works,and some of the readings I get
from it.
http://w5gi.com/mysteryantenna.htm

thanx all
Howard
VE4ISP
ps. thanx to all that commented on my G5RV post

Here is one guys thoughts on it:

http://www.coolweb.ws/genesis/Downlo...%20Antenna.pdf

Regards,
JS

"Howard Kowall" wrote in
:

Hello All

....
I guess it has it place) I have decide to try something new and
hopefully better.Here it is, the Mystery Antenna,I had all the parts
....

Now, lets see... that the "multi-band wire antenna that performs
exceptionally well even though it confounds antenna modeling software".

Yet another 'magic' antenna who's 'magic' cannot be explained!

Of course the claim is nonsense, the antenna can be modelled in NEC...
just the complication is evaluating an equivalent load in NEC terms for
the TL stubs.

You can evaluate the equivalent impedance of a s/c stub of 16.5' of RG8X
(or whatever you used) using the calculator at
http://www.vk1od.net/tl/tllc.php.

For example Z of s/c stub of 16.5' of RG8X at 7.1MHz is around 2.97
+j64.54, so it acts like a quite lossy inductor at that frequency.

Once the feedpoint impedance is found, the transmission line losses and
ATU losses can be evaluated for a system perspective.

Ask yourself why they choose to not model the antenna. Often, when people
claim that an antenna can't be modelled in reality just don't like the
answers.

Owen

Owen Duffy wrote:

...
Ask yourself why they choose to not model the antenna. Often, when people
claim that an antenna can't be modelled in reality just don't like the
answers.

Owen

I think they did model it, and compared the results against actual
hands-on observations, readings, contacts, etc.

This is why they make the claim NEC is missing something ... they simply
believe their eyes, ears and meter readings and signal reports ...

Regards,
JS

John Smith wrote:
Owen Duffy wrote:

...
Ask yourself why they choose to not model the antenna. Often, when
people claim that an antenna can't be modelled in reality just don't
like the answers.

Owen

I think they did model it, and compared the results against actual
hands-on observations, readings, contacts, etc.

This is why they make the claim NEC is missing something ... they simply
believe their eyes, ears and meter readings and signal reports ...

Let's not forget the possibility that they didn't know how to model the
thing. I'm no great shakes at modeling, and that antenna is beyond my
prowess at the present.

Of course, I'm mpore likely to assume that discrepancies between
computer world and reality are my fault. Some others might assume that
the data they input was correct, so it must be the programs fault....

And some on the fringe might say the antenna CAN't work - the computer
says it can't!

- 73 de Mike N3LI -

Michael Coslo wrote:


Let's not forget the possibility that they didn't know how to model the
thing. I'm no great shakes at modeling, and that antenna is beyond my
prowess at the present.

Of course, I'm mpore likely to assume that discrepancies between
computer world and reality are my fault. Some others might assume that
the data they input was correct, so it must be the programs fault....

And some on the fringe might say the antenna CAN't work - the computer
says it can't!

- 73 de Mike N3LI -

Absolutely, I am NOT making any statement "they" are correct (I have
never tried this antenna myself--either as a model or as an actual
antenna in reality.)

But, anyway you cut it, and on the ground floor, there ARE discrepancies
in the basic equations, formulas and assumptions being put to use in the
NEC, someday these will be fleshed out ...

Regards,
JS

John Smith wrote:
Michael Coslo wrote:


Let's not forget the possibility that they didn't know how to model
the thing. I'm no great shakes at modeling, and that antenna is beyond
my prowess at the present.

Of course, I'm mpore likely to assume that discrepancies between
computer world and reality are my fault. Some others might assume that
the data they input was correct, so it must be the programs fault....

And some on the fringe might say the antenna CAN't work - the computer
says it can't!

- 73 de Mike N3LI -

Absolutely, I am NOT making any statement "they" are correct (I have
never tried this antenna myself--either as a model or as an actual
antenna in reality.)

But, anyway you cut it, and on the ground floor, there ARE discrepancies
in the basic equations, formulas and assumptions being put to use in the
NEC, someday these will be fleshed out ...

Regards,
JS

I doubt that any antenna an amateur is likely to build has some physics
not adequately modeled by the math in NEC. Exactly what might be these
discrepancies in equations, formulae and assumptions? Considering that
NEC has had decades of validation against actual measurements and a lot
of really, really smart people looking at how it works, I'd be kind of
surprised.

However, I can also easily believe that an amateur (or professional)
could build an antenna that has measured performance different than
expected from their NEC model of that antenna. The differences would
lie, most likely, in these areas:
1) Inaccuracies in the model itself. Things like earth properties (NEC
assumes uniform dielectric, it isn't) are an important source of error
for antennas close to the ground. Most amateur models do not include a
very good model of the surroundings (supports, trees, feedlines, etc.)

2) Inaccuracies in the measurements or not measuring the right things. A
good example is using NEC to get feedpoint characteristics, then
measuring at the rig, and not properly accounting for the transmission
line, particularly if the feedpoint Z is reactive.

In the professional antenna world, if someone models an antenna, then
builds it and tests it on the range, and the measurements differ from
what the model predicted, the usual assumption is that what was built
differed from what was modeled, or the measurements were off.

On Sep 29, 11:04*pm, John Smith wrote:
Owen Duffy wrote:
...
Ask yourself why they choose to not model the antenna. Often, when people
claim that an antenna can't be modelled in reality just don't like the
answers.

Owen

I think they did model it, and compared the results against actual
hands-on observations, readings, contacts, etc.

This is why they make the claim NEC is missing something ... they simply
believe their eyes, ears and meter readings and signal reports ...

Regards,
JS

The evaluation of this antenna should start with connecting a choke
type BALUN at the input to isolate feedline radiation. A few feet of
wire draped across some tree limbs can let you talk to the world.
There have been an awful lot of hams who have thought they just
invented the best antena out there while talking off their coax.


Jimmie

JIMMIE wrote:


The evaluation of this antenna should start with connecting a choke
type BALUN at the input to isolate feedline radiation. A few feet of
wire draped across some tree limbs can let you talk to the world.
There have been an awful lot of hams who have thought they just
invented the best antena out there while talking off their coax.


Jimmie

Absolutely. The "truth" does have a way of outing itself ...

However, not so very long ago, I did just that ... and being ignorant to
just how much the coax (transmission) line was serving as an antenna--I
lived in ignorant bliss ... I can't say I wasn't happy! LOL

However, being the control freak I can be, I wanted that antenna "doing
its' correct job"--when my ignorance had been dispelled (well, I am
working on that one wink.)

Man! I have to read that paper one more time! ... LOL

Regards,
JS