Group: Recently received the above calibrator for my HW-32A, but alas, no spec sheet, instruction sheet, or Sch. diagram...anybody got the poop sheet on this little 100Khz xtal cal..... And I note a tube socket on the top, like maybe for a 6AU6 or some such firebottle...any clues out there?? Thanks 73 Ray W2KBR/3