Short Range Device
When operating as a short range device under EN 300 220-2 V3.2.1 for Ofcom IR2030/2/6 or IR2030/2/7:
1. The user must operate the Aprisa SR+ radio within all the applicable requirements of IR-2030
2. The transmitter power must not be set above +27 dBm
When operating as a short range device, the Aprisa SR+ radio TX power can be adjusted over the range of
+10 dBm to +27 dBm (average power).
To determine the maximum power to be set on the Aprisa SR+ radio, it is necessary to take into account the
feeder loss and antenna gain.
1. ERP limit (specified in dBm, in the case of IR-2030 this is +27 dBm) ERP
dBm
2. Peak to average power ratio Px
dB
QPSK 3 dB
16QAM 5 dB
64QAM 6 dB
ACM 6 dB
3. Antenna gain specified in dBd (if given in dBi subtract 2.15 dB from the given value) G
dBd
4. Feeder coax loss between Aprisa SR+ radio and antenna (specified in dB/m) L
dB/m
5. Length of feeder coax between Aprisa SR+ radio and antenna (specified in metres) d
m
From the above information, the power setting of the Aprisa SR+ radio (P
dBm
) can be calculated to ensure
operation within the regulatory requirements using the formula:
P
dBm
= ERP
dBm
+ (d
m
x L
dB/m
) - G
dBd
- Px
dB
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