SWR meter with jumper cable

SWR kit – Precise tuning for your 27MHz antenna

Do you want to precisely tune the SWR of your 27MHz antenna? This SWR kit includes a CRT-1 SWR meter and a 90 cm jumper cable, allowing you to easily achieve optimal tuning. A correct SWR value is essential for a long transmission range and prevents damage to your CB device.

With this set, you can accurately measure the SWR value and properly tune your antenna. Please note that the measurement should be performed outdoors, in an open environment, for the best results.

How to correctly tune the SWR of your 27MC CB antenna

A correct SWR (Standing Wave Ratio) adjustment is essential for an optimal transmission range and to prevent damage to your CB device. Follow the steps below carefully to get the best performance from your antenna.

Step 1: Preparation

1. Place your vehicle or antenna in an open environment – Avoid tall buildings, trees, or metal structures in the immediate vicinity.
   
2. Connect the CB device to a stable power source (~13.8V).
   
3. Use the included jumper cable to properly connect the SWR meter:

Connect the CB radio to the SWR meter via the RTX connector (Transmitter).
Connect the antenna to the SWR meter via the ANT connector.

Step 2: First measurement on channel 1

1. Turn on your CB radio and select channel 1.
   
2. Set the SWR meter to the ‘FWD’ (Forward) position.
   
3. Press and hold the transmit button (PTT) on the microphone and turn the calibration knob (‘CAL’ or ‘SET’) until the meter deflects to maximum.
4. Switch the meter to the ‘REF’ (Reflected) position and note the measured SWR value.

Step 3: Measurements on channel 20 and channel 40

Repeat the above procedure on channel 20 and channel 40.
Compare the three measured SWR values to determine if the antenna is too long or too short.

Step 4: Adjusting the antenna based on measurements

• Is the SWR too high on channel 1? → Antenna needs to be longer.
  
• Is the SWR too high on channel 40? → Antenna needs to be shorter.
  

Ways to adjust the antenna

Depending on your antenna type, adjust the length as follows:

• Loosen the top nut: For antennas with an adjustable top, you can slide the top part in or out and then secure it again. These antennas sometimes have a removable cap (antenna tip cap) that you must remove first to access the adjustment screw.
  
• Loosen the hex bolt: For some magnetic antennas and models like the Stinger, use a small hex key to slide the antenna whip in or out.
  
• Screw in or out: For fiberglass antennas (such as the Firestik), remove the rubber cap and turn the screw to adjust the length.

Step 5: Repeating the measurements

Perform measurements again on channels 1, 20, and 40. Adjust the antenna again if necessary until the SWR is as low as possible (ideally between 1.2 and 1.5, never in the red area).

Step 6: Completion and check

1. Securely tighten the top nut, hex bolt, or screw to maintain the antenna adjustment.
   
2. Check that all cables are properly connected and that the antenna is firmly in place.
   
3. Remove the SWR meter and connect the antenna directly to your CB device.

Important tips:

Do not stand too close to the antenna during measurement, as this can affect the reading.
Keep transmit time during measurements as short as possible to prevent overheating.
Set the CB radio's power as low as possible to prevent incorrect measurements.

With these steps, you will get the most out of your 27MC CB antenna and enjoy an optimal transmission range!