Jump to content

PACTOR

From Wikipedia, the free encyclopedia

PACTOR is a radio modulation mode used by amateur radio operators,[1] marine radio stations,[2] military or government users such as the United States Department of Homeland Security & its cybersecurity agency CISA,[3][4] and radio stations in isolated areas to send and receive digital information via radio.[5]

PACTOR is an evolution of both AMTOR and packet radio;[6] its name is a portmanteau of these two technologies' names. PACTOR uses a combination of simple FSK modulation, and the ARQ protocol for error detection and data throughput.[7] Generational improvements to PACTOR include PACTOR II, PACTOR III, and PACTOR IV which are capable of higher speed transmission. As PACTOR was designed to operate as a shortwave HF band radio, it commonly operates at frequencies between 3 MHz and 30 MHz.[8]

History

[edit]

PACTOR (Latin: The mediator) was developed by Special Communications Systems GmbH (SCS) and released to the public in 1991.[6]

PACTOR was developed in order to improve the reception of digital data when the received signal was weak or noisy.[6] It combines the bandwidth efficiency of packet radio with the error-correction (CRC) and automatic repeat request (ARQ) of AMTOR.[7] Amateur radio operators were instrumental in developing and implementing these digital modes.[9]

Current uses

[edit]

PACTOR radio equipment consists of an HF transceiver, a computer and a terminal node controller.[2] Software running on the computer drives the terminal node controller.[2][10] The most commonly used amateur program for this purpose is Airmail.[2][8]

PACTOR is used by Amateur Bulletin board system operators to exchange public messages, and open conversations across the world.[2] It is also used by the NTSD (digital) portion of the ARRL's National Traffic System (NTS) to pass digital ARRL Radiograms.[11] Newer PACTOR modes are used to transfer large binary data files and Internet e-mail, particularly via the Winlink global e-mail system.[2][8]

The SailMail network transfers e-mail on behalf of marine stations.[12]

Technical characteristics

[edit]

PACTOR is a set of standardized modes used by radio operators for FSK radioteletype transfer of digital information over shortwave bands.[13][7]

Effective radio-frequency communications over long distances over hostile radio paths require that special attention be paid to the rate at which data is repeated and error correction.[14]

To reduce the amount of data sent, on-line data compression is utilized, along with memory ARQ error correction.[15]

PACTOR utilizes time-division duplexing for bidirectional, half-duplex communication. To do this, it utilizes a single frequency to send and receive data by alternating transmission time, usually with 1.25 to 1.4-second cycles; this is opposed to using separate frequencies for sending and receiving data (Frequency-division duplexing).[7][16]

Depending on the version of PACTOR protocol used and the radio-frequency conditions, PACTOR transmission speeds range from 20 to 5200 bits per second (bit/s; net rate) or 9000 bit/s gross rate utilizing speed 10 (32-QAM).[17][18]

The International Telecommunication Union (ITU) emission designators:

  • Pactor I is 340HJ2D or 440HJ2D (at a symbol rate up to 200 symbols per second).[19]
  • Pactor II is 450HJ2D (at a symbol rate of 100 symbols per second).[19][14][20]
  • Pactor III is 2K20J2D (at a symbol rate of 100 symbols per second).[19][21][22]
  • Pactor IV is 2K20J2D or 2K40J2D (at a symbol rate up to 1800 symbols per second).[19][23][18]

Availability and monitoring

[edit]

A robust network of PACTOR stations has been established to transfer data between radio stations and the Internet, extending Internet access to sea-based and other isolated users, led by volunteers involved with Winlink, under the auspicies of ARSFI (a Florida-based non-profit organization).[24]

Pactor modes other than level 1 (P1) are not open source,[25][26] but are publicly documented[27] and can be monitored and decoded easily over the air by third parties using free Raspberry Pi software ("PMON for Raspberry Pi")[28] or PMON utility on the modem itself.[29]

See also

[edit]

References

[edit]
  1. ^ Bateman, Richard; Loveridge, Ben (21 April 2025). "3". HamStudy Technician License HamBook (2022-2026 ed.). HamStudy. p. 3.6. ISBN 978-1967466009. Retrieved 11 April 2026.
  2. ^ a b c d e f Corenman, Jim (6 April 2020). "PACTOR/SSB Installation". SnailMail. Retrieved 11 April 2026.
  3. ^ "SHAred RESources (SHARES) High Frequency (HF) Radio Program". Cybersecurity and Infrastructure Security Agency. United States Department of Homeland Security. Retrieved 11 April 2026.
  4. ^ Wood, Gary; Chua, Ken. "SCS Pactor Modems Homeland Security and Emergency Services Organizations Discount Policy" (PDF). Farallon.us. Farallon Electronics. Retrieved 11 April 2026.
  5. ^ "SCS DR-9400 Review: PACTOR Modem for Reliable Off-Grid & Maritime Communication" (Video & Text). Ham Radio Therapy. No. Ham radio articles. 7 January 2026. Retrieved 11 April 2026.
  6. ^ a b c Helfert, Hans-Peter (October 1991). "PACTOR—Radioteletype with Memory ARQ and Data Compression". QEX Magazine: 3–6.
  7. ^ a b c d "PACTOR". ARRL. The National Association for Amateur Radio. Retrieved 11 April 2026.
  8. ^ a b c "PACTOR: WHEN COMMUNICATION MATTERS, RELIABILITY IS THE ONLY THING THAT COUNTS". WIMO. WiMo Antennen und Elektronik GmbH, Inc. Retrieved 11 April 2026.
  9. ^ Anderson, Eric (28 February 2023). "Amateur Radio Contributions Advance Radio Technology". Morse Nexus. PreppComm. Retrieved 11 April 2026.
  10. ^ "PTC Plus - The PACTOR Controller" (PDF). SCS. 95 SCS GmbH. 1994. pp. 2–3, 5. Retrieved 11 April 2026.
  11. ^ "What is the National Traffic System (NTS)?" (PDF). ARRL. American Radio Relay League (ARRL®). Retrieved 11 April 2026.
  12. ^ "Sail-mail e-mail service for yachts via Iridium, Inmarsat, or SSB". Sail Mail. Retrieved 1 September 2010.
  13. ^ "PACTOR Packet Teleprinting Over Radio" (PDF). Wavecom. WAVECOM ELEKTRONIK AG. Retrieved 29 May 2021.
  14. ^ a b The PACTOR-2 Protocol (PDF). SCS Spezielle Communications Systeme GmbH.
  15. ^ PACTOR-2/3/4 Advanced Data Compression (PDF). SCS Spezielle Communications Systeme GmbH.
  16. ^ Bakare, B.I.; Godwin, J.E. (23 December 2021). "X-Raying Time Division Duplexing (TDD) in Long Term Evolution (LTE)" (PDF). American Journal of Engineering Research. 10 (12). AJER: 89–97. ISSN 2320-0847. Retrieved 11 April 2026.
  17. ^ "More on comparisons of digital HF modes". News. PACTOR. Retrieved 1 September 2010.
  18. ^ a b "Technical details on the Pactor-IV protocol". p4dragon.com. PACTOR IV. Archived from the original on 23 October 2015. Retrieved 25 November 2022.
  19. ^ a b c d "Summary on SCS Waveforms" (PDF). SCS. Spezielle Communications Systeme GmbH & Co. KG. Retrieved 1 June 2021.
  20. ^ "Characteristics of systems operating in the amateur and amateur-satellite services for use in sharing studies" (PDF). International Telecommunication Union. 2017. ITU-R M.1732-2.
  21. ^ The PACTOR-3 Protocol (PDF). Spezielle Communications Systeme GmbH.
  22. ^ "Characteristics of HF radio equipment for the exchange of digital data and electronic mail in the maritime mobile service" (PDF). International Telecommunication Union. 2021. ITU-R M.1798-2.
  23. ^ The PACTOR-4 Protocol (PDF). Spezielle Communications Systeme GmbH.
  24. ^ "Original request to FCC for Pactor I in Amateur Radio by ARRL". 1995.
  25. ^ "Pactor I open source published in QEX, TAPR, 1994". Archived from the original on 9 November 2015. Retrieved 25 November 2022.
  26. ^ "Downloads". www.scs-ptc.com. Archived from the original on 25 March 2018. Retrieved 25 November 2022.
  27. ^ "PMON". www.scs-ptc.com. Retrieved 28 November 2024.
  28. ^ "Update Info DR7X00 vers. 1.17". p4dragon.com. Archived from the original (PDF) on 14 June 2020. Retrieved 25 November 2022.
[edit]
Retrieved from "https://en.wikipedia.org/w/index.php?title=PACTOR&oldid=1348197678"