[Elecraft] K3 + W2

[Ron D'Eau Claire]

They will never be equal for two reasons:

1) The K3 measures SWR between the final amplifier output and the KAT3 input
inside the K3. The function of the KAT3 is to provide a load very close to
50 ohms to the final amplifier, regardless of the impedance present at the
rear-panel antenna jack and that's what the K3's SWR meter reports. The only
way to get close to the same readings is to bypass the KAT3 and connect a
load close to 50 ohms to the W2 output. 

2) Even so, there will likely be discrepancies. SWR meters are not precision
impedance-monitoring devices. There is no reason for them to be, so one
meter will disagree somewhat from another meter. And, as Bill says, any
transmission line between the two monitoring circuits will affect the
readings unless the impedance of the load is exactly 50 ohms. The variation
caused by the line is a function of the length of the line in wavelengths,
so the discrepancy is larger as the frequency goes up.

Ron AC7AC

-----Original Message-----

Once additional connections and coax length is introduced into a load that
is not the same as the output impendence you will not see the same.  I have
come to accept that the results will be different in-line, unless some
tuning is added to each measurement device to remove the circuit reactance
created by each device. I accept the difference and use remote tuning to
eliminate these issues.

Bill
K9YEQ

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Dohn Smythe
Sent: Sunday, February 20, 2011 11:10 AM
To: elecraft at mailman.qth.net
Subject: [Elecraft] K3 + W2

Is there an accurate way to utilize a W2 with the K3/ATU combo?  Seems that
with the W2 between the output of the K3 and the Antenna, the peak reading
would not be accurate.  Especially at QRO power settings.  I don't remember
seeing anything in either of the menus that would assist with that.
73 
Dohn Smythe  N8EWY