diff --git a/lib/packjt.f90 b/lib/packjt.f90
index 0f110941b..d7d90fb46 100644
--- a/lib/packjt.f90
+++ b/lib/packjt.f90
@@ -65,7 +65,8 @@ subroutine packbits(dbits,nsymd,m0,sym)
    if(callsign(1:4).eq.'3DA0') callsign='3D0'//callsign(5:6)
 
  ! Work-around for Guinea prefixes:
-   if(callsign(1:2).eq.'3X') callsign='Q'//callsign(3:6)
+   if(callsign(1:2).eq.'3X' .and. callsign(3:3).ge.'A' .and.          &
+        callsign(3:3).le.'Z') callsign='Q'//callsign(3:6)
    
    if(callsign(1:3).eq.'CQ ') then
       ncall=NBASE + 1
@@ -269,7 +270,8 @@ subroutine packbits(dbits,nsymd,m0,sym)
    endif
 
 999 if(word(1:3).eq.'3D0') word='3DA0'//word(4:)
-   if(word(1:1).eq.'Q') word='3X'//word(2:)
+   if(word(1:1).eq.'Q' .and. word(2:2).ge.'A' .and.                 &
+        word(2:2).le.'Z') word='3X'//word(2:)
 
    return
  end subroutine unpackcall