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Old December 23rd 03, 01:40 AM
Jerry Bransford
 
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"w4jle" W4JLE(remove this to wrote in message
... I have never, ever, understood this
preoccupation with SWR. I am guessing it
comes from the CB world where getting one's "SWR's down" was the holy
grail...


When running low power, like CB'rs and QRP operators do, I can easily
understand the "preoccupation" with SWR. And when I used to run vacuum tube
transmitters in the USAF, SWR was important then too... high SWR levels were
not good for the finals.

Jerry
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Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
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Old December 23rd 03, 04:12 AM
w4jle
 
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While a transmitter looking into an impedence mismatch can be a problem,
transforming the impedence the transmitter sees satisfies the transmitter
and has no effect on antenna SWR. Everybody's happy, nothing changes as far
as SWR.

An interesting exercise, compare an antenna cut so that is 1:1, change it so
that the SWR is now 3:1 and tell me what difference one would observe at the
receiving end.

You may use a tuner to match the transmitter to the newly adjusted antenna.


"Jerry Bransford" wrote in message
news:E2NFb.25033$gN.5459@fed1read05...
"w4jle" W4JLE(remove this to wrote in message
... I have never, ever, understood

this
preoccupation with SWR. I am guessing it
comes from the CB world where getting one's "SWR's down" was the holy
grail...


When running low power, like CB'rs and QRP operators do, I can easily
understand the "preoccupation" with SWR. And when I used to run vacuum

tube
transmitters in the USAF, SWR was important then too... high SWR levels

were
not good for the finals.

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.cox.net/jerrypb/




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Old December 23rd 03, 06:14 AM
Jerry Bransford
 
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"w4jle" W4JLE(remove this to wrote in message
...
While a transmitter looking into an impedence mismatch can be a problem,
transforming the impedence the transmitter sees satisfies the transmitter
and has no effect on antenna SWR. Everybody's happy, nothing changes as

far
as SWR.


Now you're changing things by adding a tuner... the net effect is that the
transmitter is now seeing a 1:1 swr. All we talked about was your claiming
there was a preoccupation with SWR... if there was no problem with a high
swr, then there's no need for the tuner you just inserted into your
justification.

There is and always will be a need to present the transmitter with the
lowest possible SWR, regardless of if it is accomplished with a well-tuned
antenna or if that is not possible, inserting an antenna tuner between the
transmitter and antenna. So you can't get away from a "preoccupation" with
SWR no matter what you like to think.

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
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Old December 23rd 03, 03:12 PM
JDer8745
 
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Someone sed:

"There is and always will be a need to present the transmitter with the
lowest possible SWR,..."
--------------------------------
It's actually to present the xmtr with the proper load impedance with or
without an actual antenna connected. If no antenna is connected but instead,
say, a dummy load, there is no SWR because there is no tl.

Jack, K9CUN


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Old December 23rd 03, 05:33 PM
JDer8745
 
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"Now you're changing things by adding a tuner... the net effect is that the
transmitter is now seeing a 1:1 swr."
---------------
So the sending end impedance is the Zo of the line. What if that value is NOT
what the xmtr needs to see for a match to its output. E.g. The tl has a Zo of
398 Ohms, the SWR is 1 so the transmitter sees a load impedance is 398 Ohms.
May be bad for the xmtr that wants to work into diffrent load, say 50 Ohms or
so.

73 de Jack, K9CUN


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Old December 23rd 03, 10:23 PM
w4jle
 
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That is pure nonsense! The tuner is only an impedence matching device. It
has NO effect on SWR.

Have you ever run mobile? Did you tune for best SWR, or best field strength?
Did they occur at the same tuning points?

If you said SWR, back to Ch 19 and co-phased antennas.



"Jerry Bransford" wrote in message
news3RFb.26455$gN.9457@fed1read05...
"w4jle" W4JLE(remove this to wrote in message
...
While a transmitter looking into an impedence mismatch can be a problem,
transforming the impedence the transmitter sees satisfies the

transmitter
and has no effect on antenna SWR. Everybody's happy, nothing changes as

far
as SWR.


Now you're changing things by adding a tuner... the net effect is that the
transmitter is now seeing a 1:1 swr. All we talked about was your

claiming
there was a preoccupation with SWR... if there was no problem with a high
swr, then there's no need for the tuner you just inserted into your
justification.

There is and always will be a need to present the transmitter with the
lowest possible SWR, regardless of if it is accomplished with a well-tuned
antenna or if that is not possible, inserting an antenna tuner between the
transmitter and antenna. So you can't get away from a "preoccupation"

with
SWR no matter what you like to think.

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.cox.net/jerrypb/




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Old December 24th 03, 02:05 AM
Jerry Bransford
 
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-
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.cox.net/jerrypb/

"w4jle" W4JLE(remove this to wrote in message
...
That is pure nonsense! The tuner is only an impedence matching device. It
has NO effect on SWR.


Of course not, for cripe's sakes would you guys stop with the looking for
any possible way to get around the 'intent' of the answer??? OF COURSE a
tuner is an impedence matching device. A tuner is used when there's no
other way to get an antenna matched to the frequency... when the antenna's
SWR is too high. Cripes, I'm sorry I ****ed you guys off for daring to say
adjusting for minimum SWR instead of the proper impedence. When I was in
the industry, I dare say no one that worked in the industry would have
batted an eye or even thought anything about it or even WORRIED about the
nano-better correctness of saying you were matching impedences instead of
getting the SWR down since that is the indication used by EVERY tuner I have
ever used to CORRECT THE IMPEDENCE... SWR. Does your antenna tuner indicate
SWR or impedence? I know mine indicates SWR. Pardon me all to hell.

Jerry

Have you ever run mobile? Did you tune for best SWR, or best field

strength?
Did they occur at the same tuning points?

If you said SWR, back to Ch 19 and co-phased antennas.



"Jerry Bransford" wrote in message
news3RFb.26455$gN.9457@fed1read05...
"w4jle" W4JLE(remove this to wrote in message
...
While a transmitter looking into an impedence mismatch can be a

problem,
transforming the impedence the transmitter sees satisfies the

transmitter
and has no effect on antenna SWR. Everybody's happy, nothing changes

as
far
as SWR.


Now you're changing things by adding a tuner... the net effect is that

the
transmitter is now seeing a 1:1 swr. All we talked about was your

claiming
there was a preoccupation with SWR... if there was no problem with a

high
swr, then there's no need for the tuner you just inserted into your
justification.

There is and always will be a need to present the transmitter with the
lowest possible SWR, regardless of if it is accomplished with a

well-tuned
antenna or if that is not possible, inserting an antenna tuner between

the
transmitter and antenna. So you can't get away from a "preoccupation"

with
SWR no matter what you like to think.

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.cox.net/jerrypb/






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Old December 24th 03, 10:55 PM
JDer8745
 
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"There is and always will be a need to present the transmitter with the
lowest possible SWR, regardless of if it is accomplished with a well-tuned
antenna or if that is not possible, inserting an antenna tuner between the
transmitter and antenna"

====================

Many years ago when transmitters had tuneable outputs, matching cud be achieved
by something called a "pi network" in the transmitter box.

This circuit resonated the final plate circuit and provided a match to the
sending end impedance of the tl. Granted the magnitude of the SWR, i.e.,
degree of mismatch, it wud match wasn't as much as modern day "tuners".

They are not antenna tuners. If they were they wud be located at the antenna,
not the hamshack.

73 de Jack, K9CUN
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Old December 25th 03, 12:00 AM
Jerry Bransford
 
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"JDer8745" wrote in message
...
"There is and always will be a need to present the transmitter with the
lowest possible SWR, regardless of if it is accomplished with a well-tuned
antenna or if that is not possible, inserting an antenna tuner between the
transmitter and antenna"

====================

Many years ago when transmitters had tuneable outputs, matching cud be

achieved
by something called a "pi network" in the transmitter box.

This circuit resonated the final plate circuit and provided a match to the
sending end impedance of the tl. Granted the magnitude of the SWR, i.e.,
degree of mismatch, it wud match wasn't as much as modern day "tuners".

They are not antenna tuners. If they were they wud be located at the

antenna,
not the hamshack.


Jack, I guess all the manufacturers that sell "antenna tuners" are totally
wrong about what it is they're manufacturing and selling. If I were you, I
would go after all the "antenna tuner" manufacturers in the below URL and
tell them they're all wrong.
http://search.cartserver.com/search/...go.x=17&go.y=9

They'll thank you for correcting them...

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.cox.net/jerrypb/


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Old December 25th 03, 01:10 AM
JGBOYLES
 
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Jack, I guess all the manufacturers that sell "antenna tuners" are totally
wrong about what it is they're manufacturing and selling.
They'll thank you for correcting them...


Jerry, that was an impressive list of tuners. But did you note that not all
of them were listed as "Antenna Tuners". Some of them were designed to sit in
the shack next to the rig. These tune the antenna plus the transmission line
system as a whole. They don't get the SWR's down, SWR remains the same on the
antenna system.
Others on the list can be mounted right at the antenna, and fed with 50 ohm
coax. They get the SWR's down on the transmission line because the 50 ohm coax
sees a Zo match.
Others on that list can be placed in the shack or at the antenna. The
function is to transform whatever impedance the tuner sees to 50 ohms. Tuner
in the shack, no SWR change, at antenna, yes. So, "Antenna Tuner", what's in a
name?



73 Gary N4AST


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