Sierra Wireless DART 200 CDPD Modem manual PN1197-00 Revision

DART 200 CDPD Modem User’s Guide 7 Vehicle Installation Considerations

In this situation, separate the antennas as far as possible and then run a field test when the two-way radio is also being used. If the DART 200 works satisfactorily you do not have a problem, but if it does not filtering is required. A bandpass filter on the two-way radio’s transmitter output eliminates harmonics that can interfere with the cellular frequencies. A band reject filter on the DART 200’s input, centered on the two-way radio’s base frequency, provides signal attenuation at that frequency to help prevent de-sensing the DART 200’s Radio Frequency (RF) circuitry: either, or both can be required. The calculation to determine the filtering usually requires an RF engineer.

If you do not have the option to field test, then the theoretical calculation approach is your only option.

PN1197-00 Revision 1.0 7-3