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PACTOR is a radio modulation mode for sending digital data via radio waves. It is most commonly used on frequencies between 1 MHz and 30 MHz. Image File history File links Broom_icon. ... For other uses, see Digital (disambiguation). ... A megahertz (MHz) is one million (106) hertz, a measure of frequency. ... A megahertz (MHz) is one million (106) hertz, a measure of frequency. ...

History

PACTOR (Latin for: The mediator) is a Frequency Shift Keyed (FSK) modulation developed by Special Communications Systems GmbH (SCS) and released to the public in 1991. PACTOR is an evolution of both AMTOR and packet radio, hence the name PACTOR. It was developed in order to improve the reception of digital data when the received signal was weak or noisy. PACTOR combines the bandwidth efficiency of packet radio with the error-correction (CRC) and automatic repeat request (ARQ) of AMTOR. Amateur (Ham) radio operators were instrumental in developing and implementing these (new) digital modes. Frequency-shift keying (FSK) is frequency modulation in which the modulating signal shifts the output frequency between predetermined values. ... In telecommunications, modulation is the process of varying a periodic waveform, i. ... AMTOR is a specialised form of RTTY. The term is an acronym for AMateur Teleprinting Over Radio and is derived from the commercial SITOR system (Simplex Telex Over radio) developed primarily for Maritime use in the 1970s. ... Packet radio is a form of digital data transmission used in amateur radio to construct wireless computer networks. ... Bandwidth is the difference between the upper and lower cutoff frequencies of, for example, a filter, a communication channel, or a signal spectrum, and is typically measured in hertz. ... Packet radio is a form of digital data transmission used in amateur radio to construct wireless computer networks. ... In computer science and information theory, error correction consists of using methods to detect and/or correct errors in the transmission or storage of data by the use of some amount of redundant data and (in the case of transmission) the selective retransmission of incorrect segments of the data. ... AMTOR is a specialised form of RTTY. The term is an acronym for AMateur Teleprinting Over Radio and is derived from the commercial SITOR system (Simplex Telex Over radio) developed primarily for Maritime use in the 1970s. ...

Characteristics

Other forms of PACTOR include PACTOR2 and PACTOR3, mostly used by amateur radio operators to transfer large binary data files, and to accomplish internet E-mail access over shortwave radio. PACTOR is also used by the commercial sailmail network for commercial E-mail transfer over FCC assigned Marine radio frequencies. Due to the closed and proprietary nature of PACTOR2 and PACTOR3, there has been some speculation that these modes may be used on shortwave to conceal the nature of the transmission. This article is about an album. ... // History of SailMail Stan Honey WA6IVA organized the SailMail Association, obtained the necessary FCC licenses, begged, borrowed, and bought the necessary equipment, wrote the internet gateway/multiple-station synchronization software, and assembled and installed the initial SailMail radio stations. ... The abbreviation FCC can refer to: Face-centered cubic (usually fcc), a crystallographic structure Federal Communications Commission, a US government organization Farm Credit Corporation/Farm Credit Canada, a Canadian government organization Families with Children from China, an adoption support organization Florida Christian College, a college in central Florida Fresno City...

Pactor level 1 has established itself in the last decade as the new standard for FSK radio teletype on shortwave amateur radio. For the first time it is possible to utilize the possibilities of an almost ideal combination of simple FSK modulation and ARQ protocol, for robust error detection and data throughput.

Amateur radio operators and Marine (non-Ham) operators use the same equipment to send and receive e-mails (to and from the internet) using the Pactor digital mode. The equipment consists of a HF transceiver, a computer and a modem that connects between the computer and the transceiver and controls the transceiver during send / receive operations. A program called "Airmail", a free download, controls the entire process, including the modem. In the Winlink ham e-mail forwarding system, base stations located all over the world accept connections from mobile (or fixed) stations and accept e-mail formated messages and place them on the internet to be delivered as normal e-mail. They also receive and hold e-mails addressed to the mobile stations and forward those messages to them when they make a connection. All the Winlink stations are networked together so the entire operation is coordinated. The mobile (user) stations have no direct access to the internet. Using Pactor-1 and a good connection, this paragraph could be sent in 4 or 5 minutes of "on the air" time. Using Pactor-2 or the even faster Pactor-3, transmission time would be reduced to 1 or 2 minutes. Basic HF radio tuning skills are required to make a successful connection.

Power efficiency

HF data transmission by radio amateurs uses medium power (100 watts) over long distances (100 to 4000 km). Such long distances over hostile radio paths require that special attention be paid to the rate at which data is repeated, and error correction. To reduce the amount of data sent, online data compression is utilized, along with a form of error correction called "memory ARQ", in which the last data packet received is held in memory and compared to the next. If BOTH are corrupt, an attempt is made to repair the original packet by combining the two. By combining these open technologies, pactor achieves a power efficiency much greater than that of packet, AMTOR, or RTTY. In information technology, a packet is a formatted block of information carried by a computer network. ... AMTOR is a specialised form of RTTY. The term is an acronym for AMateur Teleprinting Over Radio and is derived from the commercial SITOR system (Simplex Telex Over radio) developed primarily for Maritime use in the 1970s. ... RadioTeleType (RTTY) is a telecommunications system consisting of two teleprinters linked by a radio link. ...

Waveform

PACTOR has a very narrow waveform and occupies the same bandspace as analog 300 baud H.F. Packet.

Image File history File links MT63_Packet_RTTY-comparason. ...

Current users

PACTOR is used by amateur radio operators for the open interchange of data, communications, and personal text. It is differentiated from pactor2 and pactor3 which is used by marine entities to access email using the commercial Sailmail network and by amateur radio operators using the free volunteer built and operated Winlink network. Cost is an important consideration when choosing Pactor equipment. Pactor-1 (Pactor Classic) is open technology and modems can be purchased in the $50-$150 price range and are in ample supply. The two "enhanced" modes, Pactor-2 and Pactor-3 use proprietary technology controlled by one German company, SCS Corp. Their prices discourage many potential users. As wireless internet connections, including satellite internet service providers become commonplace, potential users are finding other ways to communicate. Pactor-2 and pactor-3 are the preferred modes because they are 3 or 4 times faster than the original Pactor-1. The new technology SCS modems are fairly simple to set up and operate and they operate well under difficult conditions. The older Pactor-1 modems can be daunting to set up and operate successfully. In the Winlink Ham E-Mail system, many PMBO's, fixed location base stations, now refuse or limit the slower Pactor-1 connections. This mode is still used by many operators, mostly cruising sailors and those living "off the grid" in remote locations who can master the technical challenges and need low-cost communication. // History of SailMail Stan Honey WA6IVA organized the SailMail Association, obtained the necessary FCC licenses, begged, borrowed, and bought the necessary equipment, wrote the internet gateway/multiple-station synchronization software, and assembled and installed the initial SailMail radio stations. ... Amateur radio station with modern solid-state transceiver featuring LCD and DSP capabilities Amateur radio, often called ham radio, is both a hobby and a service that uses various types of radio communications equipment to communicate with other radio amateurs for public service, recreation and self-training. ... Winlink, also known as the Winlink 2000 Network, is a worldwide radio messaging system that mixes internet technology and appropriate amateur radio technologies to deliver advantages not possible with each alone. ...

See also

• shortwave
• radioteletype
• Hellschreiber

A solid-state, analog shortwave receiver Shortwave radio operates between the frequencies of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz) [1] and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than... RadioTeleType (RTTY) is a telecommunications system consisting of two teleprinters linked by a radio link. ... The Hellschreiber or Feldhellschreiber was a facsimile-based teleprinter invented by Rudolf Hell. ...

External links

• http://www.scs-ptc.com/pactor.html

Sources referenced

• History of Amateur Radio, by Thierry, ON4SKY