User guide
SATELLINE-3AS NMS / NMS Epic / NMS 869 / VHF
User Guide, Version 1.0
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SYSTEM ENVIRONMENT
Data protocol
Interface types
Maximum response times
Time delays
LOCAL RADIO TRANSMISSION
REGULATIONS (AUTHORITIES)
Available radio channels
Max. Radiated power
Tx/Rx duty cycle
GEOGRAPHY
Station locations
Topographic profiles
Buildings or other obstacles
8
SYSTEM DESIGN
8.1
General
A. PLANNING NETWORK REQUIREMENTS
Like other engineering tasks, designing a radio modem network requires a set of rules to be
followed for producing the desired result. Both the radio connections themselves and the
compatibility of the surrounding system need to be considered.
The very first part of the designing is to evaluate the system environment requirements,
geography and the local radio frequency and transmission laws and regulations.
B. PLANNING NETWORK HARDWARE
With the desired system performance and the limitations above in mind, the first version of the
radio modem network can be designed:
1. Radio modem types and serial cable wirings are specified.
2. Radio links are simulated by giving the antenna types and heights, feeder cable lengths,
and possible need of any additional repeater stations.
3. If necessary, other system components like RF filters, RF relays, combiners, lightning
protectors, power supplies and mechanical installation parts are specified.
4. Data transmission delays are calculated for the sufficient number of RF channels.
After these four steps, the system design is typically detailed enough for a commercial
quotation.
C. TESTING THE COMPONENTS BEFORE FINAL INSTALLATION
Data communication tests at the factory, radio signal propagation and radio interference tests
on the field are important. The tests verify the functionality of the designed system, its
compatibility to the surrounding system and the correct settings of the devices. Proper signal-to-
interference margin (app. 15 – 20 dB) is essential for reliable error-free radio communication.