DOZENS of requests on moving 20mtr SST to 15mtrs, so here is how I
did it. If you make changes or improvements other than these, please let
me know so I can use them as well.
These are standard values from any handbook
L2, L3 = 11turns #26 on T37-6(yellow)
C34, C36 = 150pf, I used silver mica
C35 = 270pf " " "
L1 = 18t #26 on T37-6(yellow)
C27 = 30pf, I used ceramic NPO VXO
X6 = 25mhz crystals. I used two, one on top, one under board.
RFC3 = 23t #26 on T37-2(red). This was a critical value
for proper oscillation and range. You may have to adjust
a turn plus or minus, or compress or spread turns to
adjust to desired tuning range.
2.2uh molded choke from base of Q2 to ground.
RFC1 to 2.7uh
As above changes were all that was neccessary to put it on 21.050 to
21.070 with the MVAM108. Output was 1 watt, so I put in MRF237(ECG341) for two
watts out. Its also very easy to move to 17mtrs by using same approach.
Good luck and 72.