Topcon SRL-35 - Transmitter; Receiver

Radio Interface
RF Interface
10
SRL-35 Operator’s Manual P/N: 1003224-01
A channel spacing of 25 kHz enables a data speed of 19200 bps and a channel spacing of 12.5 / 20 kHz
enables, correspondingly, a data speed of 9600 bps. The data speed of the radio interface is always fixed
(19200 bps or 9600 bps) irrespective of the data speed of the serial interface. If the data speeds of the radio
interface and the serial interface differ from each other, the radio modem will buffer the data in transfer
temporarily, so no data loss will occur.
Transmitter
The output power of the transmitter is adjustable. The greatest allowable power depends on limits set by
local authorities, which should not be exceeded under any circumstances. The output power of the
transmitter should be set to the smallest possible level, which still ensures error free connections under
variable conditions. Large output power levels using short connection distances can, in the worst case,
cause disturbances to the overall operation of the system.
A product variant providing 25 W power levels is available by separate order.
Receiver
The sensitivity of the receiver depends on the channel spacing of the radio modem (=data speed of the
radio interface) and on the mode of the FEC (error correction) according to the table below:
Table 10. Typical output power levels
OUTPUT POWER dBm
10 W +40
20 W +43
25 W +44
35 W +45,4
Setting the radio data modem output power level to that which exceeds the regulations
set forth by local authorities is strictly forbidden. The setting and/or using of non-
approved power levels may lead to prosecution. Topcon and its distributors are not
responsible for any illegal use of its radio equipment, and are not responsible in any way
of any claims or penalties arising from the operation of its radio equipment in ways
contradictory to local regulations and/or requirements and/or laws.
Table 11. Receiver Channel Spacing and FEC
Channel
spacing
FEC OFF FEC ON
25 kHz -108 dBm -111 dBm
20 kHz -111 dBm -114 dBm
12.5 kHz -111 dBm -114 dBm