IRA-ARQ

IRA-ARQ

Frequencies	3 MHz,30 MHz
Frequency Range	3 MHz - 30 MHz
Mode	USB
Modulation	FSK
ACF	—
Emission Designator	—
Bandwidth	650 Hz,1.35 kHz
Location	Worldwide
Short Description	IRA-ARQ, also known as BULG-ASCII and ASCII-ARQ, is a high data rate ARQ FSK system used by Bulgarian, Slovakian, and Czech diplomatic stations. The maximum speed of this mode has been seen to reach 1200 bd. Not seen much much nowadays
I/Q Raw Recording	—
Audio Sample

IRA-ARQAutomatic Repeat reQuestAutomatic Repeat Query, also known as BULG-ASCII and ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, is a high data rate ARQAutomatic Repeat reQuestAutomatic Repeat Query FSKFrequency-Shift Keying system used by Bulgarian, Slovakian, and Czech diplomatic stations. The maximum speed of this mode has been seen to reach 1200 bdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second.. IRA-ARQAutomatic Repeat reQuestAutomatic Repeat Query uses the ASCII (ITA-5 or IRA) alphabet charset. Some transmissions of IRA-ARQAutomatic Repeat reQuestAutomatic Repeat Query can be decoded using an ASCII decoder.

This mode is typically found with baudBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second. rates of 75, 100, 110, 150, 180, 200, 240, 300 or 600 bdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second.. Faster baudBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second. rates have also been seen.

Samples

300Bd 500Hz Shift	600Bd 600Hz Shift

800Bd 800Hz Shift	1000Bd 1000Hz Shift

Log

DX log from 1990's

Y/M/D
960205 0734 0734  8008.00 ???                 Czech MFA, Prague           300.4bd/400 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, crypto fm "Praha" to "PARIZ,LISABON,STRASB"    
961017 2121 2121  8065.30 DOR***              Bulgarian MFA, Sofia        300bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc                                              
971218 1848 1848  8068.20 DOR***              Bulgarian MFA, Sofia        300.2bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc                                            
970211 1843 1843  9068.30 ???                 Bulgarian Diplo, ???        300bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc                                              
951227 1359 1359  9276.00 DOR***              Bulgarian MFA, Sofia        300bd/500 ASCII ARQAutomatic Repeat reQuestAutomatic Repeat Query System                                            
960215 0759 0759  9288.00 ???                 Czech/Slovak/Bulgarian E    300bd/400 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, crypto tfc                                       
960229 0729 0729  9942.14 ???                 Czech/Slovak MFA, ???       300.5bd/200 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, crypto                                         
960401 0649 0649 10154.30 DOR***              Bulgarian MFA, Sofia        75bd/500 Baudot, Call-up "olg olg olg qap"  then into ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query       
951229 1242 1242 10705.00 ???                 ???, ???                    300bd/425 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query System, crypto                                    
991214 0332 0332 10875.80 AG7L                US Mil, ???                 75bd/165 ASCII, 5LGs and 5FGs tfc                                     
961227 0846 0846 11146.77 DOR***              Bulgarian MFA, Sofia        300bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, sync, burst, ACFAutoCorrelation Function=11                              
981015 2113 2113 11153.20 DOR***              Bulgarian MFA, Sofia        300.3bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc                                            
960618 2059 2059 11164.30 DOR***              Bulgarian MFA, Sofia        300bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, Call-up in 75bd/500 Baudot to "PMO" Washington   
981015 2236 2236 11664.00 ???                 ???, ???                    300.3bd/700 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc                                            
960826 0827 0827 12204.75 DOR***              Bulgarian MFA, Sofia        362.4bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, ACFAutoCorrelation Function=10                                         
970402 1352 1352 12207.95 ???                 ???, ???                    212.8bd/400 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, opchat "je tu obcas"                           
951128 1433 1433 12219.04 OMZ?                Slovak MFA?, Bratislava?    300bd/400/E ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, MSG to Athens, ends "cau++"                    
970509 0747 0747 12221.00 ???                 Czech/Slovak Diplo, ???     300.5bd/400 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, Crypto                                         
961228 1318 1318 13426.30 DOR***              Bulgarian MFA, Sofia        272.74bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc                                           
970123 0821 0821 13456.00 DOR***              Bulgarian MFA, Sofia        300bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc with filename RA_001.AIN                     
970222 1347 1347 13838.00 COY851***           Russian Intel, Havana       300.5bd/500 ASCII, 5LGs to YFC QSX 14417kHz                           
981015 2035 2035 13932.00 DOR***              Bulgarian MFA, Sofia        300.1bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc                                            
961227 0903 0903 13933.30 DOR***              Bulgarian MFA, Sofia        362.3bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, ACFAutoCorrelation Function=11                                         
960826 1124 1124 14479.00 ???                 ???, ???                    300.6bd/420 ASCII ARQAutomatic Repeat reQuestAutomatic Repeat Query, ACFAutoCorrelation Function=11 on tfc, opchat in 300bd ASCII           
970402 1408 1408 14760.24 ???                 Bulgarian Diplo, ???        300bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, Call-up in 75bd/500 Baudot                       
961229 1444 1444 14830.27 DOR***              Bulgarian MFA, Sofia        300bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc after "zar 300" in 75bd RTTYRadio TeleTYpe                 
970402 1251 1251 14871.30 DOR***              Bulgarian MFA, Sofia        600bd/600 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, Uuencode-like tfc                                
991105 1223 1223 15937.90 ???                 Czech/Slovak Diplo, ???     212.5bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, crypto                                         
990514 2025 2025 16015.25 DOR***              Bulgarian MFA, Sofia        210.3bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, MSG ends "73 88 sk"                            
980825 2140 2140 16303.60 Y7YOD***            US SIGINT Training, ???     75bd/170 ASCII, "ryryryry 4FGs elbf de y7yod pse kkk"                 
970406 1446 1446 16312.30 DOR***              Bulgarian MFA, Sofia        150bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc                                              
980907 2030 2030 16320.20 ???                 Czech/Bulgarian Diplo, ???  210.3bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc                                            
981216 1329 1329 16353.00 OMZ66               Slovakian MFA, Bratislava   212.8bd/550 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc                                            
991207 1415 1415 18318.00 OMZ66               Slovak MFA, Bratislava      212.5bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc                                            
961231 0949 0949 19060.27 LZV2                Bulgarian Embassy, ???      300bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, crypto to DOR on QSX 20362.3kHz                  
981127 1425 1425 23108.30 ???                 Czech/Bulgarian Diplo, ???  362.3bd/500 ASCII-ARQAutomatic Repeat reQuestAutomatic Repeat Query, tfc

Video Examples

• IRA-ARQ Analysis and decoding signals

Decoding Software

Hobby Level Software

• Sorcerer

Professional Equipment/Software

• go2DECODE
• go2MONITOR
• Hoka Code 300-32
• Wavecom W-Code
• Wavecom W-Spectra
• Rohde&Schwarz CA100

Additional Links

• shoc Database: BULG-ASCII
• WAVECOM Database: BULG-ASCII
• NumberOddities.NL Page 8 and 20, IRA-ARQ info
• Scancat info
• Percoms info
• Lief Dehio's FSK modes