PK-232 MBX – OPERATING MANUAL PACTOR OPERATION
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CHAPTER 11 – PACTOR OPERATION
11.1 Overview
Pactor is a relatively new Amateur data communications mode. It was developed in Ger-
many by Hans-Peter Helfert, DL6MAA and Ulrich Strate, DF4KV. Pactor combines some of
the best features of both AMTOR and Packet as well as providing a few new features. Pactor
operates at 100 bps or 200 bps depending on radio conditions. Pactor also contains a 16 bit
CRC to provide near error-free operation as does Packet and can also selectively use a data
compression scheme (Huffman encoding) to increase the throughput when transmitting
text. Pactor uses an 8 bit word, allowing the use of the full ASCII character set.
When data blocks are repeated in the case of an error, the receiving unit can often combine
the information in the repeated blocks to provide a good block without the need of receiving
a perfect block. This scheme is called memory ARQ.
Like AMTOR and Packet, Pactor has two basic modes of operation, an ARQ mode (Automatic
ReQuest for reception) and a non-linked mode used for CQ calls and roundtable operation.
o ARQ Pactor is a handshaking protocol that allows two stations to communicate in a
near error-free fashion. When listening to an ARQ Pactor communication, you will
hear a 0.96 second burst of data from the information sending station followed by a
short burst from the data receiving station that is an acknowledge (ACK) or non-ac-
knowledge (NAK). The NAK is sent by the receiving station when the CRC indicates
an error in the data block. Like packet, Pactor is mark-space polarity independent.
The Pactor protocol alternates the data polarity with every transmission.
o The unproto(col) mode of operation is a non-linked type of operation. It is used for
roundtable operation or for calling CQ. The unproto mode repeats the data blocks a
selectable number of times and can use either 100 or 200 bps. It also uses the CRC
error check.
11.2 Where to Operate Pactor
Before you can operate Pactor, you must first know where the activity occurs. Most Pactor
operation occurs on the 20-meter amateur band between 14.065 and 14.085 MHz. Pactor
activity can be found on the other HF amateur bands as well and in most often located be-
tween 65 and 90 kHz up from the bottom of the band as it is on 20 meters. On 80 meters,
most Pactor will be found between 3660 and 3690 kHz. Pactor is not sensitive to the side-
band used, but we recommend using LSB as in RTTY and AMTOR operating modes.
11.3 PK-232 Pactor Parameter Settings
Pactor is a bit more complex than Baudot or ASCII operation. Pactor operation requires you
to have MYPTCALL or MYCALL entered before you can operate. If you do not enter MYPT-
CALL, the call in MYCALL will be used as the default callsign. Pactor stations can't use the
SubStation XDentification number (SSID) in MYCALL.
11.3.1 Entering Your Callsign (MYPTCALL)
If you have not already done so, enter your call after the commnand prompt (cmd:) using
the MYPTCALL command. For example, if your call is WX5FAP, you would type:
cmd:MYPTCALL WXSFAP<Enter>
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