[Antennas] coax 'sweet lenght'

[dtx]

What?

Any SWR that exists on the transmission line comes from the load end.

If you have a 50 ohm output transmitter and connect it to a 75 ohm coax, 
the "SWR/mismatch" occurs inside the transmitter.  If connects to a 
75+j0 antenna, there is no SWR on the coax...nothing reflects back.  If 
you have a 50 ohm coax on your 50 ohm transmitter to the same antenna, 
there IS a reflection and there is an SWR on the coax.  If there is 
something besides +j0 the phase between I and V will cause a complex 
impedance transformation.

Yes?

Gary WA6DTX

Pat W wrote:

> Let me see if I can simplify this furthur.  A 1/2 wavelngth of coax is 
> not
> required-if the Z0 of the feedline is the same as the Zin of the  
> transceiver.
> In this case, there is NO SWR transformation going on, no matter what 
> the  feedline length.
>  Only when the Z0 of the feedline and the Zin of the transceiver are  
> different will there
> be a SWR transformation.
>  Pat W0OPW