> Jeff you have just made two statements that are the
> exect opposit of each other. If changing the length
> of cable makes a differance, then the swr as seen by
> the transmitter must change.
Re-read what I said. Changing the cable length changes the *Z*, but it
doesn't change the *VSWR*. As you vary the cable length, the Z changes in a
cyclical fashion, but always remains at a constant VSWR. For any given
VSWR, there are an infinite number of complex Z's that will produce that
VSWR.
> As some transmitters can not be tuned for impedance
> mismatch, adding lengths of line may change the
> impedance where the transmitter will produce the
> maximan ammout of power out.
Yes. But it doesn't change the VSWR.
> If say the duplexer is setup for a 50 ohm load and the
> transmitter wants to load into a 60 ohm load, then
> changing the length of cable between the duplexer and
> transmitter may let the transmitter see 60 ohms
> instead of 50 ohms.
Not if the cables your using are also 50 ohms. If the duplexer presents a
50 ohms like you said, you can use whatever cable lengths you want and the
resulting Z as seen by the transmitter will always be 50 ohms. Transmission
lines only act as transformers when their characteristic Z is different than
the termination Z.
--- Jeff
-----------------------------------------
Jeff DePolo - [EMAIL PROTECTED]
Broadcast Sciences LLC, Valley Forge PA
v: 610.917.3000
f: 610.917.3030
