STE BK77 Operating And Service Manual Download Page 2

STE  sas     Milano - ITALY 

 

Page 2 of 14 

 

General Description 

 

The BK77A5 and the BK77B5 are “PLL” synthesized UHF transceivers for use in Wireless 
“Voice” ( Analogue Signal ) or “Data” transmission applications. 
The transceivers operate on the 433.05-434.79 MHz ISM Band and are designed to comply to 
the European Standards EN 300-220-3 ( class I ) and EN 301-489-3. 
The transceivers employ NBFM ( Narrow Band Frequency Modulation ) with a 25 KHz 
channel separation. The programming frequency step is 12.5 KHz. 
 
A) BK77A5 

 

 

 

The BK77A5 is designed in accordance with  CEPT-ERC/REC 70-03 recommendation 
( Annex 1 – Non specific short range devices ) for applications employing a 10 mW 
max radiated power ( ERP ). 

 
B) BK77B5 

 

The BK77B5 has 500 mW output RF power ( 100mW in “ Low Power” ) and it is 
programmable from  432 MHz to 436.1 MHz  ( to cover also the Italian 436.000-
436.100 MHz  Telemetry and Data transmission  band ). 

 
 
 
 
 
 
 

 

 
 
 
 
 
 
 
 
 
 
 
 

Fig. 1 

CEPT ERC/REC 70-03     ISM  434 MHz   Band. 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Annex 1 –  NON SPECIFIC SHORT RANGE DEVICES 

 
 

ERP = 10 mW 

Duty-cycle < 10% 

433.05 

434.75 

MHz 

Pout 

10 

mW 

 

434.79 

Summary of Contents for BK77

Page 1: ...MUNICAZIONI Via Maniago N 15 20134 Milano Italy Tel 39 02 2153524 2153525 2157891 Fax 39 02 26410928 www stecom com ste stecom com PLL NBFM SYNTHESIZED VOICE DATA TRANSCEIVER 433 05 434 79 MHz ISM BAN...

Page 2: ...n with a 25 KHz channel separation The programming frequency step is 12 5 KHz A BK77A5 The BK77A5 is designed in accordance with CEPT ERC REC 70 03 recommendation Annex 1 Non specific short range devi...

Page 3: ...B 5R A 5V IC3A TP XF4 CER DISCR Q4 IF AMP Q5 IF 21 4 MHz XF2 2 LOCAL CER FILT OSC 2 L O ADJ Q2 AMP Q1 LNA XF1 FILTER T R D1 D2 IC9 3V 5V 5R Q15 Q14 5T Q17 TXD Q16 PTT 600 S3 IC7B AUDIO LEVEL ADJ COMP...

Page 4: ...UTPUT POWER a BK77A5 low high b BK77B5 low high 10 80 80 400 15 100 100 500 mW mW mW mW 3 SPURIOUS EMISSION 40 36 dBm FM DEVIATION 3 5 KHz R T SWITCHING TIME 5 10 ms 4 MODULATION VOICE MODE PM MOD VOI...

Page 5: ...SQUELCH LEVEL 2 L O FREQ ADJ VCO TUNE TP1 FREQ ADJ n 1 n 20 F1 FUSE 19 20 17 18 15 16 13 14 11 12 10 9 8 7 5 6 4 3 2 1 D V DATA VOICE CHD CHC CHB CHA RF CHANNEL PRO PRI PROGRAMMING TTL LEVEL 5 VDC RS...

Page 6: ...d TX power HI LO Fig 6 MCU to transceiver typical connection Data mode J1 2 1 3 5 7 9 11 13 15 17 19 20 5 VDC 4 6 MCU S MONITOR CAR DECT PTT RXD TXD CTS D C B A DATA VOICE ARX RSI CD CHANNELS SELECT J...

Page 7: ...onnections in Voice mode analogue signals J1 2 1 3 5 7 9 11 13 15 17 19 20 5 VDC 4 6 MCU PTT RXD TXD CTS CHD CHC CHB CHA DATA VOICE ARX RSI CD J1 2 1 3 5 7 9 11 13 15 17 19 20 5 VDC 4 6 S RX AUDIO OUT...

Page 8: ...ag 8 of 14 Fig 9 Transceiver total control DATA mode by external host microcontroller TX RX frequency power J1 2 1 3 5 7 9 11 13 15 17 19 20 4 6 MCU RXD TXD TX RX DATA VOICE ARX MONITOR RSI S CD CAR D...

Page 9: ...illator see block diagram Fig 2 to provide a flat response from 4 8 KHz down to DC Note In DATA operating mode the TX VOICE analog input ATX J1 pin n 9 is not disabled Signal on ATX input must be avoi...

Page 10: ...operation on default channel n 1 Serial mode programming software is available for the BK7XX transceiver for further details contact the STE sales office TABLE 1 CHANNEL CHD CHC CHB CHA 1 1 1 1 1 2 1...

Page 11: ...exchanged between the radio and the PC as ASCII characters programs such as HyperTerminal can be used to send and receive the ASCII strings of characters Serial protocol format 9600 Baud 8 data bit 1...

Page 12: ...ERATION MODE ASWER FORMAT XXXX CR LF RADIO STATUS T TRANSMISSION R RECEPTION RADIO MODE V VOICE D DATA SELECTED CHANNEL HEX FORMAT 0 TO F X 4 HEX DIGITS NT OR RT NUMBER CR CARRIAGE RETURN ASCII CODE 0...

Page 13: ...o this a 0 bit must be inserted as n 6 bit into the calculated NT and NR binary numbers A NT calculation 1 nT number nT TX FREQ KHz 12 5 2 Write down nT in binary format 16 bit 3 Insert a 0 into nT as...

Page 14: ...2 433 2625 L 0EA5 0135 4 3 433 2875 L 0EA7 0137 5 4 433 3125 L 0EA9 0139 6 5 433 3375 L 0EAB 013B 7 6 433 3625 L 0EAD 013D 8 7 433 3875 L 0EAF 013F 9 8 434 3125 L 0F39 0209 10 9 434 3375 L 0F3B 020B...

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