Mobile Antenna Installation Advice

To get the very best performance from your ZCG Scalar mobile antenna, we provide the following important installation advice. The general principles explained here apply to our entire range of vehicle mount antennas :

  • Mobile antennas.
  • AM/FM Radio Receive antennas.
  • Cellular Mobile Phone antennas.
  • CB Radio antennas.

ZCG Scalar supply an “Installation Guide” with every antenna.

Selecting the antenna mount position

The very best antenna performance will be achieved by following these general principles :

  1. Mount the antenna in as high a place as possible.
  2. Mount the antenna as far away from other antennas and metallic objects as possible to avoid interference and distortion of the 360° omnidirectional radiation pattern.
    At least 350 mm side clearance is desireable, preferably more.
  3. Mount the antenna vertical, not at an angle.

Leave some slack in the antenna cable !

You must leave some slack in the antenna feeder cable, regardless whether the cable bottom exits or side exits from the mobile antenna.

Leaving a stress relief loop in the cable will permit the antenna to flex in the usual manner during travel without placing unnecessary tension on the cable.

Failure to follow this advice will most likely result in the feeder cable being ripped out of the antenna! This issue is not covered under warranty.

Wrong ! The mobile antenna cable is too tight.CORRECT. There is a stress relief loop in the mobile antenna cable

Wrong ! The mobile antenna cable is too tight.CORRECT. There is a stress relief loop in the mobile antenna cable

Route the antenna feeder cable carefully

Route the antenna feeder cable carefully to your radio or mobile phone. A damaged feeder cable is a cause of high VSWR and reduced performance.

  • Avoid high heat areas in the engine bay.
  • Ensure that the cable is not stretched excessively and there are no sharp kinks.
  • Use cable ties, but do not pull so tight as to crush the cable.

Stainless steel cable ties are highly recommended and offer significant benefits over the black nylon type.

Fit the connector properly

To make installation simple, many ZCG Scalar mobile antennas are supplied with the connector already fitted. However, others like CB Radio antennas require that you fit the connector.

Refer to the Installation Guide for the correct cable preparation trim dimensions.

Otherwise, cable trim dimensions for all of our connectors can be found in the ZCG Scalar Product Catalogue which is available to download.

How to field tune a mobile antenna

Where the ZCG Scalar mobile antenna must be field tuned to the desired frequency using an SWR Meter, follow this procedure :

  1. IMPORTANT : Secure the antenna in the intended final position before commencing the field tune process. This is important since tune will vary in different locations.
  2. Connect the antenna to your SWR meter and the meter to your radio.
  3. Set the correct frequency range and power band on the SWR meter.
  4. Tune your radio to the desired centre frequency.
  5. Press and hold the transmit button on the microphone of your radio and check the SWR reading on the meter.
  6. If SWR is greater than 1.5:1, loosen the grub screw in the antenna ferrule holding the stainless steel whip to the point where you can remove the whip. For a fibreglass whip, remove the top cap.
  7. For a stainless steel whip, trim a short 2 mm length from the bottom of the whip. Insert the whip back into the ferrule.
    For a fibreglass whip, trim 2 mm from the top of the whip. Then replace the top cap.
    It is important to trim only short lengths gradually.
  8. Repeat step (5) and check the SWR reading of the meter again.
  9. Repeat this trimming process very gradually until SWR reduces to less than 1.5:1 at the desired centre frequency.
  10. Finally, for a stainless steel whip, tighten the grub screw to firmly secure the whip. For a fibreglass whip, replace the top cap.
  11. Disconnect the SWR meter and attach the feeder cable to your radio.

The field tune process is now complete.