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Next, measure the VSWR at the lowest and highest frequency of the operating band of the
transceiver. If the antenna has a wide enough frequency range and band-pass, the VSWR
readings should be below 1.5 to 1 across the entire operating band. If at the lower or upper
end of the transceiver operating frequency , the VSWR measures more than 1.5 to 1, it is
recommended that the antenna is re-tuned before operating on those frequencies.
If you are experiencing unusual VSWR readings check for the following possible problems:
1. Make sure that the antenna is installed properly and grounded.
2. Check all coaxial cable and connectors for defects and poor routing.
3. Went testing a vehicle installation, make sure that all vehicle doors are closed.
4. Do not test near or around large metal objects or buildings.
7. Ignition Noise
In certain vehicle installations, electrical noise or interference may be present in the receive
audio of the transceiver. Typically the vehicle’s ignition system or more specifically the
generator generates this noise. The MAGNUM MULTI is equipped with a noise blanker
circuit that is designed to eliminate most or all of this electrical noise.
In extreme cases, the noise blanker may not eliminate all the electrical noise. In such
cases, an alternator ignition noise filter can be used. The PLF-10C Filter Cord by Magnum
International is designed for use with the MAGNUM MULTI and is an effective way to
eliminate alternator and ignition noise problems.