[Elecraft] Re: [Icom] Opinions re: HF Verticals?

[George, W5YR]

John, I really don't know if you are anal retentive or not, but an antenna
can be resonant and still present a 10:1 SWR to the feedline.

The absolute magnitude of VSWR is not an indicator of resonance.

Resonance is solely, only and always the condition of a tuned circuit in
which the impedance at the port of interest is purely resistive or real.
The real component may NOT be the same as the Zo of a transmission line,
hence the SWR can be other than 1:1.

Resonance has nothing to do with SWR. SWR is determined solely by the ratio
of the driving point impedance of the antenna to the Zo of the transmission
line, or vice versa.

It is your choice to place so much emphasis on SWR but the facts are that
it is relatively unimportant to the actual radiation performance of an
antenna. An antenna fed with a line having any SWR will radiate all the
power it receives. If the line is low-loss, it can easily be the case that
more power is delivered to the antenna over a line with a 20:1 SWR than a
line with a 2:1 SWR. It is all a question of relative line loss, frequency,
line length, etc.

But the resonance or lack thereof of the antenna has very little to do with
it. Every antenna that I use, except for my Butternut HF9V vertical, is
non-resonant in any amateur band. They all work great on 80 through 10
meters, and most of my operating is QRP CW where efficiency counts.

With all respect, John, a review of the Antenna Book on the topics of
antenna resonance might be worth your time. Walt Maxwell's "Reflections II"
will give you an entirely new outlook on this subject. Resonance is
convenient for matching purposes, but that is about all it buys for you.

BTW, how are you measuring those 1.01:1 and 1.03:1 SWR values? And what do
you figure that they provide for you that 1.5:1 would not? Just curious . .
.   <:}

73/72, George    
Amateur Radio W5YR -  the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489      Icom IC-765 #2349     Icom IC-756 PRO  #2121


kc4kgu@ENTERZONE.NET wrote:
> 
> On Mon, 14 Oct 2002, Hank Kohl wrote:
> 
> > The Sigma5 is 20-17-15-12-10M with relay control to change bands.
> > A friend of mine used a couple of these on his last trip to the Pacific and
> > said they performed great.
> > Not bad for $349 and very portable.
> >
> > 73    Hank    K8DD
> 
> I just looked at the site and it looks "interesting" except for the fact
> that they claim 2:1VSWR over an adjustable 320Khz segment of 20m.  Am I
> just anal retentive of are there others out there that consider any
> supposedly resonant antenna that presents a 2:1 VSWR as a NON-RESONANT
> antenna?
> 
> If I want 2:1, I can switch in most any of my antennas, on nearly any band
> and get very close to 2:1 with no tuner.  When it comes to resonant
> antennas, I want to see 1.2:1 or better and will spend quite a bit of time
> looking for as close to 1.0:1 when putting up an antenna.
> 
> My 75m antenna is 1.01:1 at 3.875 (one of my ragchew favs) and the 160m
> loop is 1.03:1 at 1.898.
> 
> I consider an antenna that requires a tuner to operate at its design
> frequnency with less than 1.5:1 to be a compromise at best.  When the fit
> hits the shan and I need to get on the air in an emergency, I don't want
> to be twiddling with a tuner and I also don't want to risk blowing up the
> amplifier.
> 
> Maybe I just think differently.  To me, the transmatch, in the grand
> scheme of things, is another potential point of failure when you're
> DEPENDING on your communications equipment for emergency comm.
> 
> For ragchew, no problem.  Twist some knobs, press the tune button, do
> whatever it takes.