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WWII Surplus Mods
ART-13 Power
Supply
I researched a lot of ART-13 power Supplies and I decided to construct my own. I am not using hard to fined chokes and tubes as some of the schematics depicted. All the parts are not critical with the exception of the resistor between pins 2 & 9. Keep as close to the 13.4 ohm value, as it are part of the metering circuit. Fair Radio has the power plug you need.
Screen Regulator for the ART-13
I could be a purest and use a couple of VR90's in series, but I decided to get into the millennium and use a 180 volt Zener. I found a voltage divider (R118, R119, R120, R121) that supplies 180 volt to the screens. R118 sets between controls "C" and "D" under the front cover, so you will have to remove the cover to gain access to the resistor. Solder a wire to the top of the resistor and feed it to the left and up behind the meter. Place a 1"piece of sheet metal horizontally between control "C" and "D" to protect the wiring and components while drilling a hole, using a #3 drill bit, down through the aluminum frame behind and to the right of the plate meter. Tap the hole using a 1/4 28 tap. Insert the Zener and twist it in to the threaded hole. (I removed half of the tread on the Zener to avoid any interference.) Solder the wire to the top of the Zener, clean , remove the sheet metal and re-assemble.
Preamp Mods
Most of the preamp Mods for the ART-13 were done before the advent of CB radio Low Impedance Microphones and High impedance Microphones were and are the most common unit. Low Impedance is better than High Impedance. The dynamic microphone input impedance of the ART-13 is 200 ohms and the average input impedance of a CB microphone is between 200 and 500 ohms so that works out pretty well. There are plenty of schematic for a High impedance Preamp and I have one on the Schematics page.
Future Mods
I'm Working on some TCS Mods such as Solid State Power Supply, increasing Front end sensitivity, IF Selectivity ETC.
ART-l3 Manual