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Apr 9 09 2:04 PM

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Click the link below to listen to and choose from all the digital mode samples below



Digital Modes Samples

Click on a digital mode below to hear a brief sample of the sound these modes make. Hopefully this page will help you identify a mode you've heard (or help me identify ones others have heard!). Many folks have submitted excellent quality, lengthy files which are no trouble for me to accept, but I do generally drop the sampling rate and length to make them more reasonable to download over a slower line. The intent here is more for recognition by ear than for signal analysis. My page focuses on what hams call "Utility" modes or "Utes". Additional amateur radio mode links are at the bottom of the page.
Send me your .wav files of digital modes not featured and I'll happily add it, paying credit where due. High sample rates and large files are encouraged. Please include frequency and user info to help ID your sample. Your comments or clarifications are always welcome. Send mail to .
Send mail to: garyhahn@wi.rr.com 3/31/2009 Uncompressed files link - good luck

Sound Acronym Description Common Freqs Links Special Thanks
CW 20 wpm Continuous Wave Continous Wave is technically a modulation scheme, but the term CW is often used interchangeably with Morse Code. This sample is keyed at 20 words per minute. Many repeaters ID in Morse Code. More info
JT65A Weak signal mode used to make contacts all over the world with 10-15 watts of power. 14075 KHz USB WSJT John KC0BMF, Bob VE2HAR
RTTY 45 baud Radio TeleTYpe Sends text as 5 bit characters with no error correction. 45 baud is the Amateur standard. 14075 KHz USB More info
RTTY 75 baud Radio TeleTYpe Same as above, except faster. Commonly used in weather data transfer. 10536 kHz USB
SITOR-A Simplex Telex Over Radio Sends data in a two frequency mode, one for sending and one for receiving an acknowledge. The brief pause you hear in this sample is where the receiving station sends the acknowledge burst. Automatic Repeat reQuest guarantees delivery.
AMTOR ARQ Amateur Teletype Over Radio As above.
SITOR-B Simplex Telex Over Radio In this case using Forward Error Correction mode, minimizing errors. Identical format used in SITOR - SImplex Teletype Over Radio, and NAVTEX - NAVigational TEleX. 14070, 6330, 518 kHz, respectively
AMTOR FEC Amateur Teletype Over Radio As above.
ROU-FEC 164.5/218.3 bd Roumanian FEC See above for FEC explanation. HF band Unknown
SWED-ARQ Swedish ARQ As above. HF band
PSK-31 Phase Shift Keyed Currently, a quite popular amateur mode providing highly readable teletext over great distances on low power on narrow bandwidth. HF band
MFSK Multi-Frequency Shift Keying Sequential multi-tone data mode near 64bps. HF band More info Van Lanphear
VFT Voice Frequency Telegraphy An older USAF RTTY-like data mode. a.k.a. VFCT - Voice Frequency Carrier Telegraphy HF band Mike McRoberts
Hyperfix A military data or sounding mode. HF band
Hyperfix As above. HF band
ALE Automatic Link Establishment Propagation sounding and messaging used by the military. HF band More info
SSTV Slow Scan TeleVision Amateur recipe mode carries images one scan line at a time by using a frequency shift for each pixel. 14230 kHz USB More info Pic from Mir on 145.985
WeFax Weather Fax Used to send weather maps and photos primarily to ships at sea and operates similarly to SSTV 8080 kHz USB
Packet 300 baud Amateur Packet radio sends data in bursts at 300 baud, and waits for an acknowledge packet from the other end before sending the next packet. 14105 kHz USB More info
Packet 1200 baud As above, but faster. 144.39 NFM, 145.030 NFM
Bell 103 modem 300 baud Used by WB9AGH weather wire in a Chicago suburb for transmission of weather info. Can be decoded with a telephone modem. 147.060 NFM Scott, Jerry in IL
EMWIN Emergency Managers Weather Information Network 1200bd and 9600bd datastreams. Not sure which one this is. Recording is via microphone, so the hollow tonality is not likely what you'll hear. Bob W0NXN. Could use a better recording.
Pactor A sort of combination of Packet and AMTOR used by ships and Amateur Radio on HF. HF band
5/6 tone paging Used for simple tone or voice pagers or ANI. This sample has 2 sequences reading 0-123456 when decoded, the first set use an optional preamble. Add'l sample from UP Railroad in CA. Steve Donnell, David Curlee
Golay Named after a mathematician Golay is a 300/600 baud paging signal developed by Motorola. Addressing and overhead is 300bd, while data is 600bd. Also, Motorola DPL uses the same protocol format as a subaudible tone set of a 23 bit repeated word sent at a 134.5 Hz rate. Gary Gray, Dan Karg
POCSAG 512 baud Post Office Code Standarisation Advisory Group A paging format originating in the UK, used widely in the US. 152, 454, 929, and 931 MHz US
POCSAG 1200 baud As above, only faster.
POCSAG 2400 baud As above, faster yet.
FLEX Another paging format common in the US. 2 or 4 level signalling as 1600, 3200, or 6400bd rates. 929 and 931 MHz US More info
ReFLEX 2-way paging (outbound sample) Reflex 50 on 940.220 Skytel, Reflex 25 on 940.8625 US Mobility. Replies from pagers are on 901-902MHz. 940MHz US. There are 4 10kHz channels embedded at 940.21, .22, .23, .24. EJ Caylor, Dan Karg, Mike Candell
ERMES European Radio MEssage System 6250 baud paging format used in Europe 169MHz in France, Hungary, Malaysia More info
AFSK Paging Link Audio Frequency Shift Keyed At the paging Tx site, this AFSK is decoded into the "digital" FSK format (e.g, POCSAG). 72-75 MHz US, also old mobile phone freqs and 928MHz Steve D.
BPL Broadband over Power Line As heard on an HF freq. BPL components are scattered about the 1-30MHz band where implemented. (sample from Australia) Andreas, Borynski
Glenayre Paging Link QAM;Quadrature Amplitude Modulation Links from paging head end to pager transmitter sites. Glenayre C2100/C2000 model control systems are likely in use. As used on what used to be an Ameritech IMTS frequency 152.54 Chuck Huffman, Mike Candell
Speedcall DTMF Dual Tone Multi Frequency Yep, just like telephone dial, but quite rapid. This particular use is for water utility telemetry. Also used for other signalling and over the air device activation. About anywhere, as DTMF falls in the passband of most transceivers anonymous in CA
MODAT Used as ANI or status indicator, precedes or follows voice. Lindsay Blanton
GE-Star Used as ANI or status indicator, precedes or follows voice. 155.445 WI State Patrol D1 Lindsay Blanton, Jake Guild
MDC1200 Used as ANI or status indicator, precedes or follows voice. 154.130 Milw FD Jake Guild
MDC1800 Used as ANI or status indicator, precedes or follows voice. Heard here with preamble and post-transmission ID Kevin H
MDC4800 Mobile Data Terminals (MDTs) used in Police squads. 858.2625, 855.7375 in Milwaukee, WI
MDC4800 (ARDIS ) Slightly different in sound, Ardis, now Motient, is a packet switched data network for two-way data transfer. formerly 854.8375 in Milwaukee
MDC4800 (ARDIS at 855.8375) Somewhat different yet in sound. 855.8375 in Milwaukee
MDC4800? SAPOL - South Australian Police 868.7625 MHz Jon in Australia
RD-LAP 9600 baud Radio Data - Link Access Protocol ? As used by a power utility in Wisconsin. Not fully verified, note similarity to 19.2k variety. 938.9375 in WI by WEPCo
RD-LAP 19200 baud Radio Data - Link Access Protocol ? Mobile Data Terminals (MDTs) used in Police squads. 856.7375, 857.2625 in Milwaukee, also ARDIS now 854.8375
DataRadioIP Mobile Data Terminals (MDTs) used in Police squads. Uses IP as addressing system and allows Voice Over IP 857.2625 Sheboygan Co, WI More info Mike Mannchen
MMP-4800 (MDI) Mobile Data Terminals (MDTs) used in Police squads and FedEx. Created by a company called Mobile Data International, which was purchased by Motorola. Charles Guerin, Eric Hoefert
Gandalf Mobile Dispatch Licensed to American United Cab in Milwaukee area, evidence of MDT usage. 152.42 in Milwaukee, WI Sean Douglas, anonymous
DDS 4800bd QPSK Digital Dispatch Systems Licensed to Yellow Cab in Milwaukee area, evidence of MDT usage, credit, GPS. 152.33 in Milwaukee, but any NFM poss More info Bob Brown
IP MobileNet 19.2kbps MDT system. TDMA voice capable using INVADR (formerly Electrocom) ( likely 4-level FSK with FEC, native IP communications) 139.375 by the WI State Patrol, 852.6125 Rock Co, WI? More Info Barry W, Jim Korth
ATCS Spec200 Automatic Train Control System 4800 baud data system somewhat similar to MDC4800. US Nationwide license to American bacon'n of Railroads (AAR) Standard 6 base and 6 mobile freqs allocated nationwide US in 935-940 band. More info Dave Huoy
EOTD End of Train Device Used to monitor and control air pressure, etc on US trains. AAR standard 1200bd FSK protocol. 457.9375, 452.9375 More info 1200/1800Hz Mark/Space
ARES Railroad Telemetry Used by the BNSF railroad. Data transmission protocol is same as ACARS, datagrams same as ATCS. 2400bd 161.325, 160.365 Northern IL More info Dave Huoy
Harmon MCS-1/2 base As used on the CP railroad in WI on the 952MHz band, base side for signal and track control. 300bd 952.28125 in Jefferson Co, WI Erik Coleman
Harmon MCS-1/2 wayside As used on the CP railroad in WI on the 928MHz band, wayside for signal and track indication. 300bd 928.28125 in Jefferson Co, WI 1186 Mark, 970 space, 300 baud, 8, E, 1. Erik Coleman
Mobile Data Systems MDS9710 - RR Base Encoded with Harmon HP-1 As used on the CN railroad on the ex-IC Dubuque Sub on the 941MHz band, base side for signal and track control. 9600bd 932.34375 at Freeport, IL
Mobile Data Systems MDS9710 - RR Wayside Encoded with Harmon HP-1 As used on the CN railroad on the ex-IC Dubuque Sub on the 932MHz band, base side for signal and track control. 9600bd 941.34375 at Freeport, IL
Union Switch & Signal 550 Flexicode base As used on the UP railroad on the 952MHz band, wayside for signal and track control. 150bd 952.13125 on the UP at Ellis, IL Doug Nipper (sample) Anonymous (ID)
Union Switch & Signal 550 Flexicode wayside As used on the UP railroad on the 928MHz band, wayside for signal and track indication. 50 bd 928.13125 on the UP at Ellis, IL Doug Nipper (sample) Anonymous (ID)
Harmon HP-1 Railroad Codeline Base 201C 2400bd As used on the CN/IC railroad on the 952MHz band, wayside for signal and track control 952.18125 on CN/IC at Tolono, IL Doug Nipper
Harmon HP-1 Railroad Codeline Wayside 201C 2400bd As used on the CN/IC railroad on the 928MHz band, wayside for signal and track control 928.18125 on CN/IC at Tolono, IL Doug Nipper
Meteor BNSF RR HLCS(HyRail Limits Compliance System) and ETMS (Electronic Train Management System) As used on the BNSF railroad nearly system-wide for vehicle location reporting, detectors, and other statuses. Also used for the West Texas MesoNet weather sensors on 44.48MHz FM. 9600bd 44.58 FM (recording is from open-squelch USB and compressed) KC9DRX
FEC RR Telemetry unknown protocol As used by Florida East Coast railroad for signal and track control. Said to sound like Motorola Intrac. 600bd. 160.455 and 161.190 FM
SEAR Used by various US railroads for grade crossing status reporting. 1200bd protocol. Some packets demodulate to ASCII printable messages. US AAR railroad VHF band
LLWAS Windshear telemetry Low Level Windshear Alert System As used at the Madison airport for a type of weather conditions monitoring system. 6 bursts from different transmitters, with about a 20 second pause between cycles. 162.275 in Madison, WI Description Chris Carter
Mobitex As used in US by RAM mobile data. 935-940 MHz band US anonymous from UK
CDPD Cellular Digital Packet Data Typically uses vacant cellular voice channels to transmit 19200 baud data. Steve Donnell
Paknet This is another British commercial data system. It uses an X.25 access system. 164 MHz UK anonymous from UK
NMT-450 Nordic Mobile Telephones control channel It is a very primitive network (first generation) and uses analog FM with 25 KHz spacing. Similar is NMT-900. 463-470 in Sweden Alex Skafidas, John Kristian Snekvik, anonymous
LoJack downlink Not sure what protocol this is, but it is used to direction find stolen vehicles and/or disable ignition. 1200bd, Binary 0 = 1.5 cycles @ 1800Hz, Binary 1 = 1 cycle @ 1200Hz 173.075 nationwide US
Cognito This is another British commercial data system 178 MHz UK anonymous from UK
IMTS idle tone Improved Mobile Telephone System Heard from a distance, a constant tone. Last system in North America decommissioned in 2002. IMTS was the predecessor to the modern cell phone. VHF and UHF allocation in the US More info Robert Johnson
GSM digital cellular Global System for Mobile This form of digital voice transmission is very common in North America, Europe, and the Middle East 890-915 MHz EU? More info
D-AMPS Cellular voice Digital-Advanced Mobile Phone Service The TDMA based digital standard for the legacy 800MHz cellular system in the US, allowing for 3 conversations per 30kHz channel. 879-881 MHz US
AMPS Cellular Control Channel Advanced Mobile Phone Service This channel tells cell phones what channel to use for voice, and other information. 879-881 MHz US More info
Motorola Type 1 (old) Trunking Control Channel This 3600 baud channel is used to tell mobile radios which voice frequency to use. 851-869 MHz band US, others More info
Motorola Type 1 (newer) or Type 2 Trunking Control Channel As above, but the sound here is nearly the same for newer Type 1, and all flavors of Type 2, except networked systems. 851-869 MHz band US, others More info
Motorola Networked Trunking Control Channel As above, Networked, or "Smartzone" systems use Type 2 style IDs, which can span across many distinct transmitter sites over a wide area. 851-869 MHz band US, others More info
Motorola ASTRO APCO-25 Trunking Control Channel This 9600 baud channel is used to tell mobile radios which voice frequency to use. ASTRO is a digital/analog voice trunked radio system. APCO P25 makes it industry standards compliant for smooth interaction with neighboring systems. 851-869 MHz band US, others More info
Motorola IMBE (ASTRO APCO-P25 Trunked) Digital Voice Improved Multi-Band Excitation - Project 25 This is to be the Common Air Interface (CAI) specified by the APCO Project 25 or P25 standard. State of MI State Police, also on a 400 MHz military TRS. The military system is not using a 9600bd control channel, but seems to be using the same voice format. More info
Motorola IMBE APCO P25 (non-trunked) Digital Voice Another variation of the CAI, like in trunked systems, but apparently the pre/post-amble is handled a bit differently. Todd Hartzel
MOTOTRBO AMBE++ ETSI-TS 102 361-1, -2, -3 Motorola's foray into digital voice for the commercial market? More info Terry Green
EDACS (Ericsson) Trunking Control Channel This 9600 baud channel is used to tell mobile radios which voice frequency to use. 851-869 MHz band US, others More info
EDACS (Ericsson) Narrowband Trunking Control Channel This 4800 baud channel is used to tell mobile radios which voice frequency to use. NIPSCO, the northern Indiana power utility has a multi-site networked system. 935-940 MHz band US More info
ProVoice (EDACS) Digital voice format incorporated into EDACS trunked systems. Warren Whitby, Peter Laws
Aegis Digital Voice (Ericsson) Digital voice format incorporated into EDACS trunked systems. More info Charles Guerin
VSLEP Digital Voice Digital voice format as used by Motorola radios prior to IMBE format. Rich Carlson
OTAR Over The Air Re-key Transmitted to DES capable radios to update encryption key. 160MHz Fed Band US Lindsay Blanton
DES Encryption Digital Encryption System? Probably the most common encrypted digital voice format. Commonly heard on same freqs as analog voice. Most prominent feature is the high pitch end of transmission tone. 160MHz Fed Band US, various PDs
DES Encryption - Trunked Same as DES, but on a Motorola trunked system. Note lack of high pitch at end of transmission Motorola TRS
KY57/58 Encryption Military Voice encryption standard, heard on aircraft/base comms here UHF air band 376.1 AM Mike Hein, others
Racal Cougar Voice Encryption Voice Encryption used by military and special law enforement units. Mostly UK. Bob
Voice Inversion Scrambling Simple voice inversion scrambling. Not digital, per se, but interesting. F1 Scanner Group Bob
TETRA Control Channel Trans-European Trunked RAdio Digital trunked radio, primarily European 390.2375 NFM in Spain; TETRA Emergency Services
­ 380-383 MHz and 390-393 MHz
­ 383-385 MHz and 393-395 MHz (if required)

TETRA Civil Systems
­ 410-430 MHz
­ 870-876 MHz / 915-921 MHz
­ 450-470 MHz
­ 385-390 MHz / 395-400 MHz Miquel in Spain, Rickey Stein, Charles Guerin, and anonymous. Need TETRA voice sample
EFJ LTR Trunking Control subaudible Logic Trunked Radio EF Johnson trunking format. This subaudible tone sequence is used to tell mobile radios which voice frequency to use. You will need a set of HEADPHONES or speakers/amplifier with plenty of bass response to hear anything as these tones are "SUBAUDIBLE". The audible tones you hear is just a telephone ring. 851-869 MHz band US, others Bruce in Colorado
M/A-Com - OpenSky Voice is a 2 slot TDMA AMBE CODEC from DVSI. Recorded from the PA state system. FedEx uses OpenSky nationwide - in Chicago it's on 860.8625 and other freqs. 851-869 MHz band Pennsylvania state system More info Ben Russell
M/A-Com - P25/IP control channel M/A-COM's P25 trunked radio system control channel. Sounds different from Motorola's breed, but apparently P25 scanners can track the control channel. as recorded from the 2008 democratic convention temporary system in Denver, CO More info thanks, anonymous!
220 MHz SEA LTR Trunking Control pilot tone Logic Trunked Radio As heard in NFM, but actually uses ACSB (similar to SSB) for voice comms. The pilot tone is transmitted about every 10 seconds. In Milwaukee, 220.0125 is one frequency, but you may have to tune up or down a bit to hear it. Sorry for the scratchy copy, I'll work on a better sample. 220-222 MHz ACSB
GE MARC-V Trunking A trunking system which does not use a control channel. No longer implemented in the US, some systems linger. More info Isidoro Hernandez, Carolina, Puerto Rico. Also Matthew Sadler.
Midland CMS Trunking Control In Jasper, IN area, also in Ottawa, Ont. David confirmed the type. 857.0875Mhz in Jasper, IN Chris in IN, David Harris in Ont
MPT 1327 Trunking Control Channel Ministry of Post and Telecom This format is very common in European countries, Australia, and South Africa. Might be commonly referred to as TaitNet. This channel is used to tell mobile radios which voice frequency to use. More info More info anonymous from UK
MPT1317 A data format found in the UK. It is a variant of MPT1327. Said to be 1200bd MPT1327 in time share mode with other sites on same freq. 86.5875 MHz UK anonymous from UK, Adam Willis
Motorola iDen (Nextel) A digital modulation scheme used by the Nextel digital cellular system. 851-869 MHz band US More info
Kenwood Nexedge Kenwood Nexedge A trunking system control channel proprietary to Kenwood. (Supports the NXDN digital voice mode.) Sounds similar to Motorola Type 2 control channel. NFM modulated bands More info anonymous from Wisconsin.
Kenwood NXDN Kenwood NXDN A digital voice modulation proprietary to Kenwood. 6.25kHz wide using DVSI AMBE++ vocoder. NFM modulated bands Analog/digital comparison using NXDN Rich Dunajewski, by David Sterrett, N1DAS
Rolling Code Inversion Voice scrambling. Possibly called "Midian". Radios by Transcrypt International? Data burst at the start is the scrambling sync required to descramble. 410-420Mhz in Quebec. Thierry Juan, anonymous
ACARS Aircraft Communications And Reporting System Used to transmit aircraft waypoint, temperature, performance, and other data between to and from the ground station. 131.55 MHz AM More info
SCADA telemetry Supervisory Control And Data Acquisition Technically this isn't a mode, but a generic term for a data acquistion means. Some of possible data protocols are SC-1801, Harris 5000/6000/XA-21, Telegyr 8979, TRW-9550, and PERT 26/31. This particular signal is heard in the Milwaukee, Wisconsin area. It is a wide signal spanning 952.250 thru 952.750 MHz with this audio being recorded from the center of 952.500 MHz WFM. I have observed directional 900MHz antennas in use at various utility shacks, so I suppose it could be monitoring or control telemetry from these. 952.50625 MHz WEPCo anonymous local
SSR Secondary Surveillance Radar used to transmit an aircraft's ID number and altitude to ground controllers. It is otherwise known as a transponder and the transmissions are referred to as "squawks". Aircraft squawk on 1090 MHz when interrogated by ground radar. Listen in SSB or AM mode. 1030, 1090 MHz
DMB Data Marker Buoy US Coast Guard drops these beacons to pinpoint Search And Rescue positions and monitor drift of wreckage. Continuous tones. This one was set to 242.65 MHz. I'm told ELT's on 121.5 sound the same. 243, 121.5 MHz AM
EAS Emergency Alert System tone sequence which has replaced the old EBS annoying tone. These new tones will be used on commercial and National Weather Service radio stations and carry location-specific emergency messages (SAME). 162.4-162.55 MHz FM, bcast radio
CompuLert FSK-FM Frequency Shift Keying Low speed FSK telemetry to monitor and sound warning sirens. Milw. Co. Emergency Management uses it for tornado siren telemetry. Voice is also on this freq. 453.375 Milwaukee, WI More info
Zetron Model 6/26 1200 baud FSK telemetry for fire station alerting. 154.175 Waukesha, WI More info Frank Monaco
Radionics Safecom Alarm system telemetry. ? Jon in Australia
LaCrosse Technology Weather Sensor FSK Used by consumer remote weather sensors to indoor displays. 433.92MHz from a RR3-433 hybrid board. "Bit Four" requests additional protocol info
Tone Controlled Remote Base Station Signals a transmitter to unkey. Audible residue of wired direct connection to repeater/transmitter site. (listen to the end of this sample to hear it) Dan Morley, thanks to Mike I for info, John bacon
GPS RTK Global Positioning Satellite Real-Time Kinematics Not sure if this is a standard protocol, but the signal is definitely being transmitted from a GPS survey unit to improve accuracy, as close as 1 cm various More Info
TAG CTX330 F1 Telemetry Formula 1 Grand Prix car to pit F1 Scanner Group Bob
Magneti Marelli F1 Telemetry Formula 1 Grand Prix car to pit F1 Scanner Group Bob
Magneti Marelli F1 Telemetry Formula 1 Grand Prix car to pit F1 Scanner Group Bob
Magneti Marelli F1 Telemetry Formula 1 Grand Prix car to pit F1 Scanner Group Bob
Pi Research Pi96 Fq Telemetry Formula 1 Grand Prix car to pit F1 Scanner Group Bob
Pi Research Pi96 Fq Telemetry Formula 1 Grand Prix car to pit F1 Scanner Group Bob
Pi Research Pi96 Fq Telemetry Formula 1 Grand Prix car to pit F1 Scanner Group Bob
TAG CTX400 F1 Telemetry Formula 1 Grand Prix car to pit F1 Scanner Group Bob
TAG CTX400 F1 Telemetry Formula 1 Grand Prix car to pit F1 Scanner Group Bob
Magneti Marelli Step 9 ECU Engine Control Unit Formula 1 Grand Prix car to pit 400.825 in Canada Charles in Montreal, Bob
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Mysteries! Heard from home or as noted.
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Mystery MDT Denmark national rescue service As used in Denmark Martin in Denmark
Mystery USAF As heard on 294.8MHz normally used by USAF for air refueling over Europe. Tigger in UK
Mystery As used by West Midlands Fire Service (UK) Paul in Birmingham
Mystery Yellow Cab As heard in Memphis, TN 152.3MHz in 2004 Adam Myrow
Mystery Inmarsat Digi Inmarsat is a commercial satellite phone provider primarily created for ship use. This was heard on one of the channels in 2004, very continuous. AOR-East 1537.8690 MHz USB Barney Hamlin
Mystery Telemetry 866.0625 in Montreal Patrice Coulombe
Mystery HF 3606 kHz 3605.82 kHz Justin KJ4EPQ
Mystery HF 3644 kHz As heard from NW Ohio. Sounds like an AMTOR-like mode to me. Mike WW8MM
Mystery HF 3831 kHz As heard from France. Bob Brown
Mystery Railroad Codeline As formerly used on the P&L RR in Kentucy for signal and track control. 4800bd 160.455 on the P&L Chris Dees
Mystery 864.0875 As used on an LTR trunked system in Milwaukee, probably an MDT of sorts.
Mystery Telemetry Possibly siren activation telemetry in Suffolk Co, NY. Possibly 46.46 MHz David Morgan
Mystery Telemetry Probably utility telemetry/SCADA on a 6.25kHz offset channel near 941.275 in NE TX. Grady Whitney
Mystery 466.175 Australia Used by United Water International Pty in Adelaide, Australia with emissions desi 16K0F1D. 466.175 AU License Mark Jessop
Mystery 154.46375 Power/water utility telemetry, at least in Northern IL, is used to control "power line caps (capacitors)" which compensate for load varitions in the power grid. 154.45635, 154.46375, 154.47135, 154.47885 US allocations anonymous in IL, please remind me what the "name" of the protocol or mode is.
Mystery 154.4x Similar to the power/water utility stuff above, on the same freq. This one from Ridgeland, MS water system. Roughly 100bd? 154.45635, 154.46375, 154.47135, 154.47885 US allocations Brian Williams
Mystery 467.9 Data from survey equipment as used by Edgerton Contractors levelling a grade, hand-held style radio visible attached to portable unit
Mystery QuickSilver QuickSilver Couriers MDTs on 864.7375 and others on an LTR trunked system in Milwaukee.
Mystery MCTS Milwaukee County Transit System uses this data for AVL fixes and misc MDT stuff.
Mystery VSELP? Pretty sure this is VSELP (Vector Sum Excited Linear Prediction) digital voice. Used in conventional mode on a MI gas utility on 451.075 and reported as used by the Secret Service in PA. Michael in PA
Mystery MDT Licensed and confirmed to Wisconsin Gas in Milwaukee area, evidence of MDT usage.
Mystery RD-LAP? Licensed to MI Gas in Grand Rapids area. Sounds like RD-LAP at an odd bit rate.
Mystery MDT Licensed to John Aegerter in Milwaukee area, evidence of MDT usage, possibly Butler, WI PD. Possibly Cerulean brand Packet-Cluster MDT service, maybe transported by a DataRadio RF modem. 152.69 in Milwaukee, WI, others More info Bob Brown
Mystery MDT Believed to be a Motorola MDT format. 453.1 in Hidalgo Co, TX T. in TX
Mystery Telemetry? In Jasper, IN area. Chris in IN
Mystery digital voice Formula 1 Grand Prix car to pit 414.175 in Canada Charles in Montreal
Mystery telem/voice Formula 1 Grand Prix car to pit, possibly scrambled, possible interspersed telemetry 457.275 in Canada Charles in Montreal
Mystery telemetry Possible survey data from local municipality. 452.825 in Milwaukee, WI
Mystery status box As used by a cement truck firm. 452.25 in Milwaukee, WI
Ontario Provincial Police Trunking VHF Modat trunking based on MDC1200 As heard in Canada. Marker channel. System phasing out in favor of ASTRO trunked. 141.450 in Canada recording in AM? Paulo Lima in Canada, David Harris
Mystery telemetry BC Forest Service weather telemetry 402.0375 in Salmo, BC Neil Walker in BC
Mystery Utility telemetry Utilicorp Canada 155.325 in Trail, BC Neil Walker in BC
Mystery telemetry Teck-Cominco 457.0125 in Trail, BC Neil Walker in BC
Mystery MDT Used by police in Netherlands Huub Roem
Mystery Possible hospital paging, sent every minute 29.9 NFM in Norway John Kristian Snekvik
Mystery Possible security company freq 142.425 NFM in Norway John Kristian Snekvik
Mystery (ISS?) Possible xmission from International Space Station's Russian Zvezda module 143.625 NFM in Norway John Kristian Snekvik
Mystery telemetry Possible power plant telem (Trondheim?) 166.250 NFM in Norway John Kristian Snekvik
Mystery Trunked Radio System Norwegian Railways - Possible trunked system? 467.700 NFM in Norway John Kristian Snekvik, Martin Kristiansen
Mystery Skytrain Skytrain in Vancouver uses this 410.7875 Jason in Vancouver
Mystery Skytrain Skytrain in Vancouver uses this 410.9375 Jason in Vancouver
Mystery Possible trunked system 834.025 NFM in Norway John Kristian Snekvik
Mystery Military in Netherlands? 455 MHz band in Netherlands Hans
Mystery Something in Canada? 424.3125 heard from Niagara Falls area Mike Trank
Mystery Fire Dispatch Used over an EDACS trunked talkgroup for FD station dispatch data. Sounds like AX.25 but does not decode. Hartford, CT EDACS system Chris Gordon
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Links! Yep, other folks are warped enough to do this too!
Amateur Radio Modes WB8NUT
Amateur Radio Modes G4UCJ
MT Utility World Brought to you Monitoring Times
UXDF Requires membership. A Yahoo group dedicated to Utility stations monitoring. With digi modes sound files.
Class C Telemetry Requires membership. A Yahoo group dedicated to CB band gadgets. With digi modes sound files.
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