Para Dynamics PDC 600

The PDC 600 is an RF Watt, SWR, and Modulation meter. Power rating was 1000 watts PEP. Three wattage settings of 10,100,1000. SWR FWD was used to set the full scale (far left knob) by keying up the CB and adjusting for the full-scale deflection (far right of the scale-red marker. The SWR knob was set to the REF position to measure the reflected power/standing wave ratio (SWR). All three readings could be read simultaneously.

Modulation was typically set in the same manner using a 1Khz tone or some have been known to whistle into the microphone while keying the mic. This was best accomplished using a dummy load as not to create unwanted noise/chatter on the airwaves.

There were a number of PDC models:

1. PDC 600

2. PDC 600P

3. PDC 600LP

4. PDC 6000
5. PDC 600T

The PDC 600P used a more sensitive meter movement on the RF power. The PDC 600LP stands for Lighted Peak. Wheat lamp bulbs were used to create a backlight for the meter movements. Some end users had been known to replace the wheat bulbs with various colored LED lamps. The PDC 6000 was the 1000watt version with a built in talk back circuit with a headphone output mono jack to monitor the transmitted audio. The PDC 600T was actually a tuner that was built by Vectronics for Para Dynamics. At the time, both Para Dynamics and Vectronics were owned by Valor Enterprises, Inc., located in Piqua Ohio (now defunct).

The frequency range of the unit is 25-30MHz. Due to the nature of the directional coupler it isn’t recommended to use outside the designed frequency range as the insertion loss is rather significant outside that frequency.

The original PDC 600 meter movements were from Sam Woo Electronics.
SWR Meter Part # 5000900
RF Meter Part # 50001900
Modulation Meter # 5002900
4X4" PDC 700 Meter # 5069900

Troubleshooting chart

Symptom	Recommendation
No Modulation- Has Set	Replace C5 0.1mfd capacitor
No Modulation/ Low Mod (Set OK)	Check D7/D8 (1N4003)
No Modulation/Low Set/Low Mod	Check D5 (1N4148)
No FWD Swing/Power	Check D2/D3 (1N4148)
No Mod /No FW Power Swing	Check C4 .0024mfd
No Talkback PDC 6000	Check Pot/Diode/Tighten bottom case screws
No Talkback PDC 6000	Check input jack
Wont Zero / Return at zero	Check front/back coil springs inside meter movement for debris
Wont Zero /Return	Adjust back pivot point spring
Low Reading on 1000 watt scale	Check D2/D3 (1N4148)
Erratic meter readings	Check wiring of meter movement internal/external connections
Erratic meter readings	Possible static in meter movement cover, spray with anti-static spray