[Elecraft] SWR question

[Michael Walker]

Without seeing the entire diagram, SWR is not a consistent value throughout
the feedline.  We actually proved this a one of my classes back in
college.  I can't remember how many jumper cables I made to up to this test
at 100Mhz.  All different wavelengths and random lengths as well.

Let me borrow something Cecil KG7BK said in a previous forum a long time
ago.








*The SWR changes every inch up and down the transmission line because
everyinch has a finite loss and because the SWR is never exactly 1/1 at
theload. _For practical purposes_ if the transmission line is matchedto the
load the SWR is close enough to 1/1. If the transmission line is not
matched to the load, the SWR decreases in the direction toward
the generator because of losses. Removing an inch of transmission
linechanges the SWR... inserting an SWR meter changes the SWR...
hopefullyby a neglible amount.*




*SWR's of 1/1, infinite and zero impedences, exactly 50 ohm antennas
andtransmission lines are human concepts that do not exist in
reality.Sometimes they are good approximations to reality and sometimes
they arenot.*


Mike va3mw

On Wed, Sep 14, 2016 at 3:55 PM, Barthold Lichtenbelt via Elecraft <
elecraft at mailman.qth.net> wrote:

> > The KAT500 Utility will show the "bypass VSWR", which is the SWR observed
> by the ATU when it is in Bypass.
>
> As will the SWR meter on the KPA500, right?
>
> Barthold
>
> -----Original Message-----
> From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Dick
> Dievendorff
> Sent: Wednesday, September 14, 2016 1:24 PM
> To: 'Joe K2UF'; elecraft at mailman.qth.net
> Subject: Re: [Elecraft] SWR question
>
> If your TX sensor is in line after the KAT500, you might be observing the
> SWR of the antenna side of the ATU. The KPA500 and KAT500 LEDs show the SWR
> at the transmitter side of the ATU, rather than the antenna side.
>
> The KAT500 Utility will show the "bypass VSWR", which is the SWR observed
> by
> the ATU when it is in Bypass.
>
> 73 de Dick, K6KR
>
>
>
> -----Original Message-----
> From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Joe
> K2UF
> Sent: Wednesday, September 14, 2016 11:49
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] SWR question
>
> Using my K3/KPA500/KAT500/P3+SVGA with the TX sensor in line.
>
> On the KPA500 the SWR reads 1.3  with one or two SWR led's  lit  also one
> or
> two led's lit on the KAT500 but the SWR display on the P3 shows about 6.
>
> Any ideas why this is happening?
>
> Joe K2UF
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