Collins Xmtr Tune & Neutralization Tips

 

Occassionally in the haste and general bustle of tuning up an S-Line transmitter, one can forget to keep the tube shield on the 6CL6.  It is imperative that the shield be in place during  RF alignment procedures and neutralization procedures.  This is true of course of all the tube shields but particularily important for the driver tube.

If one has a signal generator, I find the most expedient method of tuning a KWM-2/2A is to tune the receiver portion (i.e. the first 3 sections of the RF deck) and then come back and tune for xmit drive.  Generally in a well behaved unit, only the driver  (4th section) need be adjusted by this procedure and it eliminates some hunt and peck.

If the plate tuning at 28.6 MHz does not dip at approximately 9 on the plate tuning scale, the open air coil may be adjusted to bring it to this point.  Other tuning and neutralization should have already been accomplished prior to any adjustments on this coil.  If dip is low, spread coil slightly.  If dip is high, compress slightly.