David Ryeburn wrote in
:

In article ,
Jet_Li wrote:

best is any vertical from Force 12 - I got one on 75 meters that
beats everything else I have put up.
got one on 40 meters from Force 12 - beats everything else I have put
up.

I went to the Force 12 website and clicked on the "Flagpole antennas"
link http://force12inc.com/F12-flagpole-ants-003.htm.

I read the "New 40 Meter Coil" portion of the page with interest --
sounded too good to be true. A moment's use of the calculator showed
that the VSWR figures and the quoted feed point impedances were very
inconsistent -- orders of magnitude wrong. The claimed SWR of 16 for
the unloaded antenna worked out really to be about 850 -- close enough
to infinity for me!

Ah, but you calculated the VSWR at the load end. They calculated the much
lower VSWR at the source end of the line.

If you were Force12, you probably wouldn't want to publicise the extreme
VSWR that users of the standard flagpole experience in this scenario.

Owen

On Thu, 15 Mar 2007 00:08:30 +0000, west wrote:

I know I can go to eham.com but I like the advice on rraa better. I also
know that this question is somewhat subjective, but if you will, please
indulge. :-)
What is flat out the best vertical HF antenna in your opinion and why?
Thanks in advance.

west
AF4GC

SteppIR. Why use a tuner to match your radio to your antenna, when you can
make your antenna match your radio?

--Teh

"Tehrasha Darkon" wrote in message
...
On Thu, 15 Mar 2007 00:08:30 +0000, west wrote:

I know I can go to eham.com but I like the advice on rraa better. I also
know that this question is somewhat subjective, but if you will, please
indulge. :-)
What is flat out the best vertical HF antenna in your opinion and why?
Thanks in advance.

west
AF4GC

SteppIR. Why use a tuner to match your radio to your antenna, when you can
make your antenna match your radio?

--Teh

No Tuner i.e. TransMatch -- The SteppIRT vertical is remotely adjustable
in length, with continuous coverage from 40 meters through 6 meters - and
every frequency in between.

A vertical antenna that is precisely adjustable in length while in the air
solves the coverage problem, and in addition has vastly improved performance
over existing fixed length verticals. The ability to tune the antenna to a
specific frequency results in excellent performance on every band - and this
means the entire band, with very low VSWR. Resonant antennas must be made a
specific length to operate optimally on a given frequency. So, instead of
trying to "trick" the antenna into thinking it is a different length (traps,
coils, etc), why not just change the antenna length? This is what we have
done with the new SteppIR verticals.

http://www.steppir.com/

CL

"Caveat Lector" wrote in
:


"Tehrasha Darkon" wrote in message
...
On Thu, 15 Mar 2007 00:08:30 +0000, west wrote:

I know I can go to eham.com but I like the advice on rraa better. I
also know that this question is somewhat subjective, but if you
will, please indulge. :-)
What is flat out the best vertical HF antenna in your opinion and
why? Thanks in advance.

west
AF4GC

SteppIR. Why use a tuner to match your radio to your antenna, when
you can make your antenna match your radio?

--Teh

No Tuner i.e. TransMatch -- The SteppIRT vertical is remotely
adjustable in length, with continuous coverage from 40 meters through
6 meters - and every frequency in between.

A vertical antenna that is precisely adjustable in length while in the
air solves the coverage problem, and in addition has vastly improved
performance over existing fixed length verticals. The ability to tune
the antenna to a specific frequency results in excellent performance
on every band - and this means the entire band, with very low VSWR.
Resonant antennas must be made a specific length to operate optimally
on a given frequency. So, instead of trying to "trick" the antenna
into thinking it is a different length (traps, coils, etc), why not
just change the antenna length? This is what we have done with the new
SteppIR verticals.

This analysis is along the lines of the traditional "resonant antennas
work better" line.

Sure, a marconi antenna that is adjusted to be a physical quarter wave on
the operating frequency has a feedpoint impedance that yields a low VSWR
on the coax, and feedline losses are relatively low, but the equivalent
loss resistance of the ground connection is significant relative to the
radiation resistance. A quarter wave marconi requires an extensive earth
system for good efficiency.

My reading of Cebik's article at http://www.cebik.com/gp/gr.html is that
simple 4 radial installations have 10 ohms or so loss resistance greater
than extensive (128 radial) systems, which themselves aren't zero loss.
The modelled feedpoint R varies from 4 to 18 ohms above the radiation
resistance of a quarter wave over perfect ground, which implies a
feedpoint efficiency of 90% to 66% respectively.

On the other hand, a longer non-resonant radiator (say approaching a half
wave) has higher radiation resistance (relative to the equivalent ground
loss resistance) which more than offsets the loss expected in a matching
network needed to operate the coax at near unity VSWR for low line loss.
Not only might the longer radiator be more efficient, but it well have a
better pattern (eg higher gain at lower angles or radiation).

It isn't clear to me that the Steppir has "vastly improved
performance over existing fixed length verticals" as you put it. With
enough radials, it is about as good as good verticals get, but there are
other good verticals that don't need as extensive a radial system.

Owen

On Thu, 15 Mar 2007 00:08:30 GMT, "west" wrote:

I know I can go to eham.com but I like the advice on rraa better. I also
know that this question is somewhat subjective, but if you will, please
indulge. :-)
What is flat out the best vertical HF antenna in your opinion and why?
Thanks in advance.

west
AF4GC

What I gather from what I read here and all the publications I can get
my hands on it is a quarter wave radiator over 130 radials that are at
least 1/4 wave long.

That may not hold true if you consider radiators longer than 1/4 wave.
"Best" is a very loose spec.

I am in the throws of constructing what I think is "Best" for me. I
started out with a 28 foot radiator and three twenty five foot
radials. It worked. It works a whole lot better now with a total of 36
radials. 14 are about 70 ft, 16 are about 36 ft, 6 are less than 36
ft.

I will work on a taller and more robust radiator next.

I feed it with a SGC-237 tuner. I can only guess the tuner losses are
similar to what a comparable tuner built from the TLW program in the
ARRL Antenna Handbook predict.

The limiting factors are the radiator, the ground and the losses.

What is "Best" for you will depend on your set of compromises.

My expectations are focused on 160-80-40 meters. It was pretty
inexpensive until I added the tuner!

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"