This conversion is very simple and can be done in about 10 minutes with only a soldering iron and a small piece of wire.  I would suggest a very small wire around #28-26 gauge works best.  Position the PRC 174S upside down and with the front face toward you.  Looking at the pictures I have taken you are giong to locate connector J11 in the front right quadrant.  Looking again at the pictures the screwdriver blade points to the 3rd pin (pin E) on connector J11.  You can see how I routed the wire and soldered it to any part of the ground plane. (correction made to read pin E by N3OC on 1/22/14)

what this does for you:  Before for SSB operation you had to have the rig in FSK mode to receive.  NOW you do not.  When you  switched to IND to see an incomming signal strength you muted the receive now you do not.

The rig will now receive in other positions and I especially want to point out the indicator function where now when you transmit the red LED graph will now display your PEP output signal as you talk, and durring recieve the same group of LEDs now act like a S meter.  Manual tells you for each LED how much signal strength.  

Ilan has aproved this modification for the PRC 174S and has preformed the mod himself.  I learned of this modification from Ilan.  I have just tried to present the procedure so everyone can preform the modification.  Have fun with your PRC 174S now improved.

Frank KD7HVL

N3OC additional note - this can also be implemented by grouding pin 5 of the rotary selector switch on the back of the front panel if you are squeamish about soldering on the mother board.