[Amps] Input SWR revisited

[donroden at hiwaay.net]

Yes, and if I add another 1/4 wave of 75 ohm cable to the length, the  
transmitter is now looking into a 2:1  ( 100 ohm )  Load
and will start folding back.

So saying :

> the SWR will always remain the same at the radio no matter what length
>  of cable is used (except for cable loss) or what the load impedance is as
> long as that load impedance remains the same.

doesn't stand the test of practical transmission line theory.


Don W4DNR





Quoting TexasRF at aol.com:

> Good question Don. You have to keep in mind that the 100 ohm load will make
>  for a 1.333 swr in the 75 ohm coax. At a length of one quarter wavelength
> the  100 ohm load impedance is transformed to 56 ohms, which is pretty close
> to 50  ohms and looks like a low swr to the radio.
>
> But, the swr inside the 75 ohm coax is still 1.333 at all points along the
> cable.
>
> 73,
> Gerald K5GW
>
>
>
>
>
>
>
>
> In a message dated 1/14/2015 12:13:49 P.M. Pacific Standard Time,
> donroden at hiwaay.net writes:
>
> 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 at 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 at contesting.com] On  Behalf Of
>>> donroden at hiwaay.net
>>> Sent: Tuesday, January  13, 2015 2:01 PM
>>> To: amps at contesting.com
>>> Subject: Re:  [Amps] Input SWR revisited
>>>
>>> Clear as Mud  .........
>>> What does it all mean ???
>>>
>>> Don  W4DNR
>>> _______________________________________________
>>>  Amps mailing list
>>> Amps at contesting.com
>>>  http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>
>
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