[Milsurplus] TCS Transmitter: OK Smart People; Why?

[Mike Morrow]

Hue wrote:

> One key point on TCS crystals not stated. They MUST be 1/2 half the 
> operating frequency.

It's not that simple...the rule stated above applies only for transmitter operation on bamd 2 (3.O to 6.0 MHz).  Are you suggesting applying that to all three bands?

Here are the instruction book's directions, expressed by me in equation form, for determining the appropriate TCS crystal frequencies:

Band  Operating Fop  Transmitter Xtal Fxt  Receiver Xtal Fxr
  1   1.5 to  3.0    Fxt = Fop             Fxr =  Fop + 0.455
  2   3.0 to  6.0    Fxt = Fop / 2         Fxr = (Fop + 0.455) / 2
  3   6.0 to 12.0    Fxt = Fop / 4         Fxr = (Fop - 0.455) / 3
     
> I would think 20 wpm is pushing it anyway for that big relay, anyway.

But that obscures the real serious defect, which the manual says will occur at slower speeds with some crystals.

Mike / KK5F