Vectronics VEC-621 - Manual (Page 2)

component tolerance when precision reading is desired, the 300 watt
range can be recalibrated as follows:
a. Set the push button switch to SET position (IN).
b. Rotate the SWR/POWER control to the 30 mark and read the power level
on the 30 watt scale.
c. Rotate the SWR/POWER control counter-clockwise until the power level
reading on the 300 watts scale is the same as it is on the 0 watts scale as
noted on Step b. above.
d. Mark the control setting for the re-calibrated 300 watt range.
3. Power Measurement (220MHz):
Power measurement on the 220 MHz operation is the same as in the 144 MHz
operation as in Step 2. However, instead of using the 30 and the 300 marks, use
the mark to the left of the 30 for 30 watt range and left of the 300 for the 300
watt range.
Antenna Operation
The ANTENNA and TRANSMITTER controls on the VEC-621 present a
minimum capacitance at "0" and a maximum capacitance at "10".
After properly installing the VEC-621, use the tuner to tune for minimum SWR
as described below.
1. Set both the TRANSMITTER and ANTENNA controls to "0".
2. Apply enough transmitter power to have an adequate indication on your
SWR/Watt meter. Do not apply full power while tuning for minimum SWR.
3. While transmitting, alternately adjust the TRANSMITTER control and the
ANTENNA control for minimum SWR. Since the TRANSMITTER and the
ANTENNA controls interact, the two controls can best be adjusted by
turning the TRANSMITTER control at a small increment at a time and then
rotating the ANTENNA control for the minimum SWR. Repeat this process
until a minimum SWR is obtained.
4. After minimum SWR is obtained, full output power up to 300 watts PEP may
be applied to the VEC-621.