True but that's not the frequency he is trying to tune it for.


"Dave Shrader" wrote in message
news:YmEFb.426478$Dw6.1312140@attbi_s02...
There is absolutely nothing wrong with a VSWR of 1.7:1!!!

Thankyou for that input Dave, i will notify the owner and see what he comes
up with.

Gary


"Dave Shrader" wrote in message
news:xiJFb.456020$275.1339004@attbi_s53...
Gary, also be aware that if this is a mobile type antenna, that is ...
short compared to a 1/2 wavelength, then resonance is not indicated by
lowest VSWR. Resonance has nothing to do with VSWR. Resonance means the
frequency where there is no reactance.

The radiation resistance of short antennas on 80 meters can be as low as
4 ohms resulting in a VSWR of 12:1 at resonance!! Measure the antenna's
resonant frequency using an MFJ 259B or equivalent.

What you may need is an auto-tuner mounted at the antenna.

Deacon Dave, W1MCE

Gary Smith wrote:

Sorry, thats SWR of around 1.7:1 at 3.7 MHz...


"Gary Smith" wrote in message
...

Hi, a friend of mine has a Yaesu RSM-2 10/80 metre antenna. He says it
has
an SWR of around 3.7 MHz and wants to lower it for around 3.57 but the
adjustable tip doesnt affect it enough. Anyone got any tuning tips or
specs/instructions/comments?

Thankyou

Gary

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

If you are talking about a mobile installation where the tl is only 6 feet
long, what difference does it make if the SWR is high? (assuming that the line
voltage is not so high that it arcs through the dielectric)

73 de Jack, K9CUN

"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

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/

-
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/

"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

"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/

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