User's Manual Part 1

TDL 450i Intergrator’s Guide 6
installations, you should not use frequencies set aside for itinerant operations, but should coordinate a
frequency based on the fixed area operation.
Regulations differ from country to country, please be aware of the local regulations before using radio
equipment.
Automatic station identification
For operation in the United States, the FCC requires that radio transmitters broadcast a station identifier
every 15 minutes. The station identifier is the call sign assigned to you on the station license.
The radios support the broadcast of station identification in a manner that meets the requirements of
the FCC. Upon receipt of equipment, use the XDLCONF software to program your FCC call sign into the
configuration of the radio. This is only required for transmitters.
The call sign is transmitted every 15 minutes in Morse code. It is not included in any data packet and so is
not processed by the receiving radio. However, data transmission is interrupted for a few seconds while the
call sign is being transmitted. If you leave the Call sign field blank (on the XDLCONF Identification screen),
the radio programmed with this configuration file will not transmit any call sign.
WARNING – Failure to transmit your station identification is in violation of FCC regulations. If you are
operating outside the United States, check with the local authorities if you need to transmit a call sign.
Carrier Sense Multiple Access (CSMA)
CSMA is a technology implemented in the radios to meet the United States Federal Communication
Commission (FCC) transmitter requirements. It is illegal to transmit on any UHF radio within the United
States without CSMA enabled. CSMA holds off the radio transmission if the frequency is currently being
used by a co-channel user. On occasion, you may note that the radio broadcasts stop for short periods of
time. Most often, this is a case of co-channel interference and the radio is holding off broadcasts due to the
FCC-mandated CSMA.
Note – You should turn CSMA off when transmitting within the European Union.
GPS RTK equipment is designed to function with intermittent gaps in the data. Heavy co-channel use may
limit the ability of the radio to transmit the required information. In areas of heavy co-channel usage, try
changing channels to a less used frequency.