TNC2.14 
While at Radio Shack, you might also want to invest $1.59 in part number 
272-1340,  5-60  pf  trimmer  capacitors to replace  C47  to  facilitate 
setting the time-of-day clock to the correct rate.
2) 59th harmonic of 2.4576 MHz output of divider U4a is 144.9984 MHz.
If the crystal is slightly high in frequency (4.9156 Mhz instead of
4.9152 MHz), this spur will fall on 145.010.  Solution is to increase
the value of C47.

3) Adding a 220 pF capacitor across U4 pins 3 to 7, a 100 pF capacitor
across U10 pins 12 to 7, and a 0.01 uF capacitor across U4 pins 6 and 7
will aid in reducing spurious rf.
 High Freq operation improved !
The followin mods from TAPR for U34 & U30 improved
the HF operation here. Obtain 2 16 pin dip headers &
do the following:

CONTINUED IN FILE TNC2.7 - REQUEST FROM SERVER