PRO2004.9 2&3) 400 CHANNEL and SPEED MOD ! On the top of the sub-circuit board, locate the slot for D-513. Count backwards from there until you get to the space for D-510. Install a diode at D-510 in the same polarity as the rest of the diodes. There, you now have 400 channels instead of 300 ! Now install a diode at D-514 and you have increased the scan speed to 20 channels/sec from 16 ch/sec. Carefully re- assemble the metal box. Make sure everything else is as it should be. RE-invert the radio so it is right side up. 4) THE SQUELCH MOD !! Now, locate a sub-circuit box under the sloping front panel. It should have many alignment holes in the top. Pry the cover off very carefully. Locate IC-2 in the left side of the pc board. It should be marked IC- 10420. Locate R-148, a 47 K ohm resistor between pins 12 and 13. Cut a lead of this resistor, But be sure to leave enough lead on both sides of the cut to solder to. Patch in a 100K ohm resistor. Make sure there are no solder balls or short circuits. Now your squelch will operate more smoothly. Again, I STRONGLY suggest you obtain the above mentioned magazines for more details. Addresses appear below. Please ignore any mis-spellings, mis grammer, etc. Good luck and good listening !!! 73 Gene WA1UXA PS, make sure you re-install the metal cover and re-install the radio in the case !!!!!!!!!!!!!!!!!! Addresses: Popular Communications 76 N Broadway Hicksville, NY. 11801 Monitoring Times 140 Dog Branch Rd P.O. Box 98 Brasstown, NC. 28902