THE SIO CODE:
SIGNAL STRENGTH INTERFERENCE
5=Excellent 5=Nil
4=Good 4=Slight
3=Fair 3=Moderate
2=Poor 2-Severe
1=Barely Audible 1=Extreme
OVERALL MERIT
5=Excellent
4=Good
3=Fair
2=Poor
1=Unusable
SINPO CODE
SIGNAL STRENGTH (QSA) INTERFERENCE (QRM)
5=Excellent 5=None
4=Good 4=Slight
3=Fair 3=Moderate
2=Poor 2=Severe
1=Barely Audible 1=Extreme
NOISE - ATMOSPHERIC (QRN) PROPAGATION DISTURBANCE (QSB)
5=None 5=None
4=Slight 4=Slight
3=Moderate 3=Moderate
2=Severe 2=Severe
1=Extreme 1=Extreme
OVERALL MERIT (QRK)
5=Excellent
4=Good
3=Fair
2=Poor
1=Unusable
