1274


    From : W3CSG @ WB4D.VA.USA.NA
      To : MFJMOD @ ALLUS
    Date : 900724/1806
   MsgID : BF 2079@WB4D, 605@KJ6YT $2079_WB4D
 Subject : More TX audio from MFJ1270B/1274
     Via : AA6QN!N6KZB!KB6GVT!WA6PEZ!G3KFN!N8GTC!WB8ICL!NC8Q!W8BI!N8LJX!KD8JR!N8ET!WB8LYF!N8FIS!WB8JUI!NO8M!WA8BXN!WB8LVP!KC8JN!KA3NVP!W3KDC!WB4D


Need more TX audio to drive a commerical radio or inject past the limiter?
The following mod will increase the stock output from a MFJ1270B or 1274
TNC from about 200mv with tone twist to about 500mv with no tone twist.

Change R56 from 7.5K to 4.7K
Jumper out cap C71
Remove cap C73
Install 1mfd caps at C34 and C35  (caps shown on board but missing)

The above changes will make the TNC TX audio the same as the older
MFJ1270 and TAPR TNC2 units.
I am presently using this mod in order to drive Motorola and GE radios
in my node stack.
73 Royce W3CSG @ WB4D.VA.USA.NA