RADIUS
Product
Description
PDR 121
iom_pdr121_04_r02.doc
Rev 02
Page 17 (67)
7.5 Radio Receiver Sensitivity
The receiver sensitivity depends on the frequency used, channel spacing, 12.5 / 25 KHz, and the
data speed, 4800, 9600 or 19200 bps. The receiver sensitivity is measured by attenuating a known
bit-pattern until bit error occurs. A standard way of presenting receiver sensitivity is for example:
-110dBm @ BER (Bit Error Rate) < 1x10
-6
This means that there is less than 1 bit error out of 1 million bits when the signal strength at the
receiver is at –110 dBm.
It is important to know that this value in many cases can depend on the bit pattern used. RADIUS
uses a random bit pattern to determine receiver sensitivity, which includes all possible bit pattern
variations. This gives a very reliable, worst case, sensitivity measure.
Using gain antennas or increasing the output power of the transmitting radio can compensate for
the radio receiver sensitivity. Using gain antennas is often the most efficient solution.
It is important to note that a very sensitive radio cannot compensate for a poor antenna installation.
The sensitivity can be used in propagation studies for radio network planning.
7.5.1 PDR 121 Receiver Sensitivity
Model
Frequency Range
[MHz]
Channel Bandwidth
[kHz]
Radio Data Speed
[bps]
Sensitivity
BER < 1x10
-6
PDR 121-A
VHF 132-150
12.5
4800 / 9600
-111 dBm / - 109 dBm
PDR 121-B
VHF 132-150
25
9600 / 19200
-114 dBm / - 107 dBm
PDR 121-C
VHF 150-174
12.5
4800 / 9600
-111 dBm / - 109 dBm
PDR 121-D
VHF 150-174
25
9600 / 19200
-114 dBm / - 107 dBm
PDR 121-E
UHF 435-450
12.5
4800 / 9600
-110 dBm / -107 dBm
PDR 121-F
UHF 435-450
25
9600 / 19200
-110 dBm / -103 dBm
PDR 121-G
UHF 450-470
12.5
4800 / 9600
-110 dBm / -107 dBm
PDR 121-H
UHF 450-470
25
9600 / 19200
-110 dBm / -103 dBm
7.6 Radio Transmitter Power
The transmitting power ranges are from 0.1 to .2.0W for VHF transceivers and from 0.01 to 2.0W
for UHF transceivers. The transmitter power is tuned as ordered at the RADIUS factory, but can be
adjusted by the user via the software configuration menu - both locally and remotely. The output
power can be tuned in steps of 1dB between 0.1 and 2.0W, (20 dBm to 33dBm), for VHF and
between 0.5 and 2.0W, (27 to 33dBm), for UHF radios.
Note!
The UHF radios can be factory tuned
between 0.01 and 2.0W. (10dBm to 33dBm).