Cecil Moore wrote:

Jim Kelley wrote:


Cecil Moore wrote:

If there is 75 ohm coax on the input of the Bird, the reflected
power reported by the Bird on the coax will be off by an infinite
percent. That's pretty inaccurate.


Why wouldn't the meter correctly indicate the reflection resulting
from the mismatch between the 50 ohm wattmeter and the 75 ohm
transmission line?


The question implies that the mismatch would cause appreciable
reflections. I have not witnessed that happening at HF but
perhaps others have. On MFJ meters, for instance, the one inch
wire through the ferrite toroid probably wouldn't cause an
appreciable mismatch.

The Bird manual shows a section of 50 ohm transmission line. But even
the N connectors are 50 ohms. I assume even one of those would show up
on a TDR.

ac6xg