[Tech-Assist] Marti STL funny readingsHere's a head scratcher.

[Gregory Muir]

In reply to:
>From: "Ronald J. Dot'o Sr."

As an additional bit of information regarding use of the Bird 43, it might 
also be worth reading the text contained on page 25 of the Bird 43 manual as 
well.  There have been times when I have had to "tune" the line length to 
get the right reading on the Bird due to the presence of VSWR.  This is 
especially true when measuring power right at the transmitter port.  But it 
has rarely been seen when measuring at the antenna end unless something is 
really out of whack.

In addition, I have found that the built-in wattmeters in units such as 
Marti and Crown transmitters can be quite finicky about giving "truthful" 
readings at times under the presence of certain reactive conditions.  The 
rudimentary fabricated sampling sections they use don't seem to tolerate 
out-of-spec conditions very well.  Merely adding a Bird to the line thus 
changing the  line length can sometimes throw things out a bit.

Greg Muir

Wolfram Engineering, Inc.
Great Falls, MT