Yes Don, with a 1/4 wavelength of 75 ohm cable you will get an impedance
transformation from 100 ohms to 50 ohms. If the cable is other than a
quarter wavelength or multiple of you will have a different impedance
transformation and see something other than 50 ohms.
But in the model that I was explaining all cables were 50 ohm cables.
The only time that there was an impedance transformation was when a tuner
was involved. The cable after the tuner changed the resonance of the tuner
which resulted in a change seen in SWR.
73
Gary K4FMX
> -----Original Message-----
> From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of
> donroden@hiwaay.net
> Sent: Wednesday, January 14, 2015 2:10 PM
> To: amps@contesting.com
> Subject: Re: [Amps] Input SWR revisited
>
> Explain the case where a 100 ohm load ( 2:1 ) can be a 1:1 swr at the
> transmitter with a length of 75 ohm cable. I've changed the cable
> length and improved the SWR.
>
>
>
> Don W4DNR
>
>
>
> Quoting Gary Schafer <garyschafer@largeriver.net>:
>
> > It means that-- if you are looking at the SWR at your radio and there
> is a
> > tuner after the SWR bridge, any changes in cable length after the
> tuner will
> > show a change in SWR at the radio if you do not touch the tuners
> tuning.
> > This assumes that the load on the end of the cable is not 1:1.
> >
> > 2nd, the SWR will always remain the same at the radio no matter what
> length
> > of cable is used (except or cable loss) or what the load impedance is
> as
> > long as that load impedance remains the same.
> >
> > 73
> > Gary K4FMX
> >
> >> -----Original Message-----
> >> From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of
> >> donroden@hiwaay.net
> >> Sent: Tuesday, January 13, 2015 2:01 PM
> >> To: amps@contesting.com
> >> Subject: Re: [Amps] Input SWR revisited
> >>
> >> Clear as Mud .........
> >> What does it all mean ???
> >>
> >> Don W4DNR
> >> _______________________________________________
> >> Amps mailing list
> >> Amps@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/amps
> >
> >
>
>
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