Someone sed:

"I always hear and read that a high SWR can destroy the PA final of TX,
cranck coils, etc."

===========

I've always heard that too. And I always heard that if you break a mirror,
you'll have seven years bad luck.

73 de Jack, K9CUN

Thierry wrote:

SNIP
Hi,

Correct. This is well what I did, rotating the amplifier load knob (a
kenwood TL922) to reduce the SWR as I could not reduce it another way
(antenna side) due to my defect balun.

73
Thierry

No! You did not reduce the VSWR!! You increased the loading of the
amplifier!

If you remember, VSWR is a measure of the impedance mismatch of the
antenna and the impedance of the transmission line MEASURED AT THE
ANTENNA. There is NOTHING you can do at the RTX/Amplifier to change it!

The PLATE and LOAD controls on your TL922 allow you vary the values of
'C' in the output stage of the amplifier and therefore vary the range of
tuning from typically 8 to 400 ohms.

DD, W1MCE

JDer8745 wrote:
Someone sed:

"I always hear and read that a high SWR can destroy the PA final of TX,
cranck coils, etc."

I've always heard that too. And I always heard that if you break a mirror,
you'll have seven years bad luck.

A high SWR can indeed destroy unprotected solid-state finals by causing
over-current and/or over-voltage. If finals cannot be damaged by the
impedance mismatch accompanying a high SWR, why do the transceiver
manufacturers waste money on protection circuitry? Of course, a tuning
network between the final and the feedline will usually alleviate the
problem through matching.
--
73, Cecil http://www.qsl.net/w5dxp



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Dave Shrader wrote:
If you remember, VSWR is a measure of the impedance mismatch of the
antenna and the impedance of the transmission line MEASURED AT THE
ANTENNA. There is NOTHING you can do at the RTX/Amplifier to change it!

Of course there is, Dave, just hit the tune button connected to your
remote auto-tuner. :-)
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore wrote:

Dave Shrader wrote:

If you remember, VSWR is a measure of the impedance mismatch of the
antenna and the impedance of the transmission line MEASURED AT THE
ANTENNA. There is NOTHING you can do at the RTX/Amplifier to change it!


Of course there is, Dave, just hit the tune button connected to your
remote auto-tuner. :-)

Gee Cecil, I didn't know you contributed to "Old Men's Tales". Next
you'll be telling us that you got your VSWR down to ZERO :-)

Dave Shrader wrote:
"Next you`ll be telling us that you got your VSWR down to Zero :-)"

Just to demonstrate that there are lurkers:
No, I`d bet Cecil would quit at 1:1.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:
Dave Shrader wrote:
"Next you`ll be telling us that you got your VSWR down to Zero :-)"

Just to demonstrate that there are lurkers:
No, I`d bet Cecil would quit at 1:1.

Heck Richard, I often quit at 2:1. :-)
--
73, Cecil http://www.qsl.net/w5dxp



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"Dave Shrader" wrote in message
news:H5cPb.89261$Rc4.431228@attbi_s54...
Thierry wrote:

SNIP
Hi,

Correct. This is well what I did, rotating the amplifier load knob (a
kenwood TL922) to reduce the SWR as I could not reduce it another way
(antenna side) due to my defect balun.

73
Thierry

No! You did not reduce the VSWR!! You increased the loading of the
amplifier!

OK, ok ok, I interpreted my result and left some words in my kbd....
In fact what I wanted to say is that in adjusting the load I see as a side
effect or for consequence to change the value read on the SWR-meter (more of
less input power, hence more or less reflected power due to a high SWR at
the end of the line, but of course most of the time the value of the SWR,
whatever the input power I used stay constant. (this is shorter to say that
my TL modified the SWR...;-))

Thierry


If you remember, VSWR is a measure of the impedance mismatch of the
antenna and the impedance of the transmission line MEASURED AT THE
ANTENNA. There is NOTHING you can do at the RTX/Amplifier to change it!

The PLATE and LOAD controls on your TL922 allow you vary the values of
'C' in the output stage of the amplifier and therefore vary the range of
tuning from typically 8 to 400 ohms.

DD, W1MCE