Decode PACTOR-I with an SDR

Group

HF utility

In the mode list

HF ARQ, 14.080 MHz

What PACTOR-I is

PACTOR-I monitor, receive only and (no real recording was available): 100 and 200 baud FSK with 200 Hz shift found automatically (tone pair, speed, shift polarity and timing), the 1.25 s ARQ cycle of both stations of a link, packets checked with their CRC-16, connect packets with the called callsign, control signals CS1 - CS4, changeovers and QRT, plain ASCII and Huffman text, repeats and….

Frequencies and settings

OnAir takes any frequency you type; the numbers above are the mode's starting point and the range its table describes. In the app the shortcut label is HF ARQ, 14.080 MHz.

What OnAir shows

PACTOR-I monitor, receive only and (no real recording was available): 100 and 200 baud FSK with 200 Hz shift found automatically (tone pair, speed, shift polarity and timing), the 1.25 s ARQ cycle of both stations of a link, packets checked with their CRC-16, connect packets with the called callsign, control signals CS1 - CS4, changeovers and QRT, plain ASCII and Huffman text, repeats and unproto / FEC broadcasts, memory ARQ (bad copies are added up). PACTOR-II, -III and -IV are proprietary (SCS) and are not supported.

Limits and what it was checked with

Checked with generated signals and impairments; recordings of real signals welcome.

Which radio you need

This is a shortwave mode, so the radio has to tune HF. An SDRplay, Airspy HF+ or an RTL-SDR in direct-sampling mode do that directly; with a HackRF an HF upconverter or a direct-sampling receiver is the usual route. A long wire or loop antenna matters more than the radio.

Receiving and the law

Questions about PACTOR-I

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