> >It doesn t matter where the min and max are on the line. The
> same amount
> >of reflected power will be seen at any point. Reflected
> power does NOT get
> >back into the transmitter. It gets re-reflected back towards
> the antenna
> >when it reaches the transmitter circuits.
>
> I don't buy into this. In order for reflected power to not
> be absorbed by
> the TX, it would have to appear totally reactive.
Not necessarily true. If there exists a conjugate match at the transmitter,
the reflected power will be re-reflected back to the load. The problem,
though, is most of our solid state repeater amps may exhibit other problems
due to the mis-matched load Z (efficiency drops, PA goes into oscillation,
whatever).
> This doesn't sound right either, as there should be no
> reflected power at
> the antenna if it's been matched further down the line.
There won't be any reflected power if the matching is done *at the antenna*.
If the matching is done at the source end of the line (via a transmatch or
similiar device), which is what I believe the topic of discussion was, then
there will be reflected power (and likewise VSWR) on the feedline if the
load (antenna) Z does not match the cable's characteristic Z.
> My guess is that the higher power reading on the wattmeter is
> due to the
> weird impedances it's seeing on both its input & output.
If placed along a length of transmission line that has a VSWR other than
1:1, a directional wattmeter (Bird or similiar) will show the sum of
forward+reflected with the slug rotated to the forward direction due to the
reflected power being re-reflected at the source end.
--- Jeff
