Theory Of Operation - Command Technologies COMMANDER VHF-2000 Manual

Theory Of Operation

The Commander VHF-1200/2000 use Genuine Eimac 3CPX800A7
ceramic/metal triode(s) in a class AB2 grounded grid configuration.
Nominal drive power of 35 to 50 watts will deliver full rating of clean RF
output power.
Metering Functions
The Commander VHF-1200/2000 have two illuminated panel meters.
The Grid Current meter provides a continuous reading of the 3CX800-A7s
grid current. The meter scale is 2 mA per division and the range is 0 to
100 MA. DO NOT EXCEED 60 mA OF GRID CURRENT ON THE VHF-
1200. DAMAGE TO YOUR TUBES COULD RESULT. Under typical
operating conditions the grid current will be 20-45 mA . Plate voltage and
Plate current are shown on the second meter. A function switch on the
front panel switches the meter from plate voltage (VP) to plate current (IP).
Plate current is shown on the top scale. Each division is 20 mA, and full
scale is 1500 mA. (1000 mA VHF-1200) The typical plate current under
nominal rated output should range from 900 to 1100 mA. (500 to 600 on
VHF-1200) with an absolute maximum of 1200 Ma. for SSB. (600 VHF-
1200) Plate voltage is indicated on the bottom scale with each division
reflecting .06 KV. The scale has a range from 0-3.0 KV. The nominal no-
load plate voltage should read approximately 2,600 volts. Plate voltage
under nominal full load should read approximately 2,300 volts.