From an estate I found 4- 21 mhz xtals for the AT-1 (no AT-1 Tho) If you remember to get on 15 mtrs with the AT-1 you quadruplied (X4). I believe the band for novice was 21.100 to 21.250 The ones I have are - 5.278-21.112 5.282-21.128 5.297-21.188 5.305-21.220 for $3 each plus $2 ship =$14 if anyone is interested Sam K5SW