[Elecraft] K3 SWR Accuracy: Final explanation

[Wayne Burdick]

There are two sources of the reported SWR inaccuracies:

- An SWR calculation scalar that I'll be adjusting in firmware; this  
is what's causing a 2:1 SWR to read closer to 1.8:1 on some K3s.

- The KAT3 itself, and to a much lesser degree, the KANT3, which is  
present if the ATU is not installed. Both modules have inherent stray  
reactance, part of which is due to the 8.2 MHz first-IF trap. These  
strays slightly alter the impedance seen by the K3's SWR bridge.

Even when the scalar correction is applied, there will still be a  
small frequency-dependent variation in SWR reading between the K3's  
bridge and an external instrument. This has no impact on K3 operation.

73,
Wayne
N6KR