Vectronics VC-300M User Manual

Page 5

VC-300M Antenna Tuner

Owner's Manual

4. If you use a linear amplifier, set it to STANDBY. Do not use the linear amplifier

until the VC-300M is tuned. Do not exceed 300 watts!

5. Set RANGE switch to 30W (button IN).

6. Rotate the TRANSMITTER, ANTENNA, and INDUCTOR controls for maximum

noise or signal as heard on your receiver.

7. Key your transmitter and adjust the power level for a reading of 40-50 watts on the

FORWARD scale. Adjust the TRANSMITTER, ANTENNA, and INDUCTOR
controls for a minimum REFLECTED reading while maintaining a FORWARD
reading of 40-50 watts using your transmitter power control.

8. Read the SWR on the red scale by switching the front panel push-button to OUT.

Repeat step 7 until the lowest SWR reading is obtained. The SWR should be 2:1 or
lower.

Note:

This procedure takes patience the first time. The transmitter and antenna
controls vary the capacitors and provide fine adjustments. The inductor control
provides course adjustment.

9. When you have tuned your antenna to the best SWR, record the settings of the

TRANSMITTER, ANTENNA, and INDUCTANCE controls on the chart on page 4.
for future reference. When you retune, use these settings as your starting point.

NOTES

1. An SWR of 1:1 is best, but an SWR as high as 2:1 may be acceptable. Check you

transmitter manual for details.

2. If you cannot get an acceptable SWR, lengthen or shorten you antenna and/or

feedlines and retune.

3. If you get low SWR readings at more than one setting, use the setting that:

••••

Gives the highest FORWARD power reading.

••••

Gives the lowest REFLECTED power reading.

••••

Uses the largest capacitance (highest number) on the TRANSMITTER and

ANTENNA

controls.

4. Any time a new or different antenna is connected, it is necessary to repeat the tuning

procedure for each antenna.