The SWARL SWL Unique Prefix Award is issued for hearing and confirming 50, 100, 150, 200, 250 etc. unique prefixes. The prefix is the first part of the call sign, defining the area of location of the operationing station. Usually this is the first three characters of the call sign.
1A4 in 1A4A
2E0 in 2E0IMS
RA6 in RA6LO
K5 in K5D
Note That in prefixes like Russian (eg RA6LO) letter "L" also defines region of location but it is NOT part of the prefix but the part of suffix. The suffix will not be cosidered to be a different prefix and RA6LO and RA6NOK are one same prefix.
Prefix award can be modulation type dependant or General (mixed mode).