I recently bought an automatic tuner (I know, I know; I wasted my
money since manual tuners are so easy to build) which could supposedly
tune "8-1000" ohms resistance. I first asked the manufacturer if
maybe they meant "impedance", and they replied
"Yes, thanks for the correction". That lead to a followup question:

( NOTE: My keyboard doesn't have keys for "plus or minus" or "square
root" so I'll use "#" and "SQRT()", respectively.)

"Does '8-1000 ohms impedance' include ALL COMBINATIONS of #X#jY SUCH
THAT SQRT (Xsquare + Ysquare) is in the range of 8 to 1000 (such as
#8+j0 to #1000+j0 and 0#j8 to 0#j1000), or are there some "holes" in
coverage?"

Their response was:

" We use the polar coordinate system and it covers all phase angles at
14 MHz. Obviously, plotted on a smith chart you would see the range
decrease as you depart from 14 MHz."

I haven't used a Smith Chart since I was first introduced to them in
college (1963!-() Could someone please translate their response to
simple English that I can understand. In particular, what range of
impedances might their tuner cover on 80 meters? 40 meters? 15
meters? 10 meters?

Myron A. Calhoun wrote:
I recently bought an automatic tuner (I know, I know; I wasted my
money since manual tuners are so easy to build) which could supposedly
tune "8-1000" ohms resistance. I first asked the manufacturer if
maybe they meant "impedance", and they replied
"Yes, thanks for the correction". That lead to a followup question:

( NOTE: My keyboard doesn't have keys for "plus or minus" or "square
root" so I'll use "#" and "SQRT()", respectively.)

"Does '8-1000 ohms impedance' include ALL COMBINATIONS of #X#jY SUCH
THAT SQRT (Xsquare + Ysquare) is in the range of 8 to 1000 (such as
#8+j0 to #1000+j0 and 0#j8 to 0#j1000), or are there some "holes" in
coverage?"

Their response was:

" We use the polar coordinate system and it covers all phase angles at
14 MHz. Obviously, plotted on a smith chart you would see the range
decrease as you depart from 14 MHz."

I haven't used a Smith Chart since I was first introduced to them in
college (1963!-() Could someone please translate their response to
simple English that I can understand. In particular, what range of
impedances might their tuner cover on 80 meters? 40 meters? 15
meters? 10 meters?

The response translates to: "The range is less at other frequencies than
at 14 MHz."

Roy Lewallen, W7EL

On Sep 11, 8:06*am, "Myron A. Calhoun" wrote:
I recently bought an automatic tuner (I know, I know; I wasted my
money since manual tuners are so easy to build) which could supposedly
tune "8-1000" ohms resistance. *I first asked the manufacturer if
maybe they meant "impedance", and they replied
"Yes, thanks for the correction". *That lead to a followup question:

( NOTE: *My keyboard doesn't have keys for "plus or minus" or "square
root" so I'll use "#" and "SQRT()", respectively.)

"Does '8-1000 ohms impedance' *include ALL COMBINATIONS of #X#jY SUCH
THAT SQRT (Xsquare + Ysquare) is in the range of 8 to 1000 (such as
#8+j0 to #1000+j0 and 0#j8 to 0#j1000), or are there some "holes" in
coverage?"

Their response was:

" We use the polar coordinate system and it covers all phase angles at
14 MHz. Obviously, plotted on a smith chart you would see the range
decrease as you depart from 14 MHz."

I haven't used a Smith Chart since I was first introduced to them in
college (1963!-() Could someone please translate their response to
simple English that I can understand. *In particular, what range of
impedances might their tuner cover on 80 meters? *40 meters? *15
meters? *10 meters?

Hi Myron,

Their response _suggests_ to me that the tuner can match loads inside
the circle on the Smith chart that's centered on the real axis and
passes through R=8 and R=1000, when used at 14MHz. I guess that's
equivalent to loads representing up to about 11:1 SWR in an 89 ohm
line. They didn't exactly say that, but it seems a reasonable guess.
It does seem like they denied that there would be holes in the
coverage.

Other than not being able to match as wide a range on other
frequencies, their response really doesn't tell me anything about the
capabilities away from 14MHz. You might be able to nail them down a
bit better if you can get them to tell you what range they can match
at 3.5MHz and at 30MHz, or other frequency you particularly care
about.

Cheers,
Tom

Myron A. Calhoun wrote:
"Does '8-1000 ohms impedance' include ALL COMBINATIONS of #X#jY SUCH
THAT SQRT (Xsquare + Ysquare) is in the range of 8 to 1000 (such as
#8+j0 to #1000+j0 and 0#j8 to 0#j1000), or are there some "holes" in
coverage?"

This should be a rhetorical question. There is no tuner on
earth that will deliver power, i.e. "match" 0+j1000 ohms.
--
73, Cecil http://www.w5dxp.com

On Sep 11, 1:23*pm, Cecil Moore wrote:
Myron A. Calhoun wrote:
"Does '8-1000 ohms impedance' *include ALL COMBINATIONS of #X#jY SUCH
THAT SQRT (Xsquare + Ysquare) is in the range of 8 to 1000 (such as
#8+j0 to #1000+j0 and 0#j8 to 0#j1000), or are there some "holes" in
coverage?"

This should be a rhetorical question. There is no tuner on
earth that will deliver power, i.e. "match" 0+j1000 ohms.
--
73, Cecil *http://www.w5dxp.com