[Elecraft] [K3] Ref Cal failed

[Martin]

Elecrafters,
a fellow ham kept telling me i am off frequency, so i performed the CAL 
REF Method2 per the instruction manual.
A 10m ssb qso with him showed that i now am within a few hz to his rx.
I then had a qso on 80m with a few SDR-guys. They told me i'm off about 
100hz. I trust them. I don't remember anyone complaining about me beeing 
off freq on 80m before.

What did i miss? Any other parameter to check?

Method 2
Before the calibration the K3 had a warm-up for at least 2 hours.
10Mhz WWV,
CONFIG:REF CAL.
S P O T on
Matched beat note to sidetone.
Accuracy to my ears was less than 1 hz (as a cw op i'm good at this)


73,
Martin