Vectronics VC-300DLP Owner'S Manual Download Page 6

VC-300DLP Antenna Tuner 

Owner's Manual

 

5.  Set OUTPUT SELECTOR switch to the proper selection on the TUNED side of the switch.  

Selecting any of the DIRECT positions by passes the tuning circuitry altogether. 

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 at the point where the two needles intersect.  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.  If the  SWR can not be reduced to the lowest reading, try 
increasing or decreasing the reading of the transmitter control.  Then, try to null the 
antenna control for the lowest reading.  You may want to try reversing this procedure 
by increasing or decreasing the antenna control and nulling the transmitter control.  
Always perform these adjustments at low power. 

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 the preceding 
page 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 your 

transmitter manual for details. 

2.  If you can not get an acceptable SWR, lengthen or shorten your 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. 

 

Summary of Contents for VC-300DLP

Page 1: ...ings Also included is a built in Dummy Load for tuning purposes which is easily switched in and out of the circuit SPECIFICATIONS FRONT PANEL INDICATORS Meter Dual movement lighted cross needle Power...

Page 2: ...The SWR is measured where the two needles intersect on the red scale 3 ANTENA Continuously adjustable output capacitor 4 OUTPUT SELECT Eight position rotary switch selects an output coaxial connector...

Page 3: ...o vary inductance 6 RANGE Two position push button switch selects the range of FORWARD and REFLECTED Power displayed on the power meter When the RANGE switch is OUT the FORWARD meter scale reads 300 w...

Page 4: ...lect a location for the VC 300DLP that allows the connectors to be free of any possible contact during operation WARNING SOME BALANCED OR END FED ANTENNAS WILL PRODUCE HIGH RF VOLTAGES AT THE BANANA C...

Page 5: ...PLIED POWER TUNING 1 Select the band and frequency of desired operation 2 Set TRANSMITTER ANTENNA and INDUCTOR controls to the suggested settings before applying transmitter power Actual settings may...

Page 6: ...not be reduced to the lowest reading try increasing or decreasing the reading of the transmitter control Then try to null the antenna control for the lowest reading You may want to try reversing this...

Page 7: ...call VECTRONICS at 601 323 5800 You will be best helped if you have your unit manual and all information on your station handy so you can answer any questions the technicians may ask You can also sen...

Page 8: ...K AVG button to AVG Apply 100 W of RF at 14 0 MHz Adjust R1 see Figure 1 so that 100 W of FORWARD power is read on the meter Reduce the RF power to 10 W and set the RANGE to10 W Adjust R2 so that 10 W...

Page 9: ...VC 300DLP Antenna Tuner Owner s Manual 9 SCHEMATIC DIAGRAM VC 300DLP...

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