Pacific Weekdays Network

This network consists of a group of transmissions over the Pacific area taking place on every weekday, successively based at the top of the hour, involving several stations of the Russian 6 operator, representing all of its digital, voice and Morse modes. The transmissions involved are organized as follows:

• F01 Pacific Weekdays from 00:00 UTC on, and then 01:00 UTC on
• F06 ID 60146 from 02:00 UTC on, and then 03:00 UTC on
• S06 ID 480 from 04:00 UTC on
• M14 ID 952 from 05:00 UTC on

Each of F01, F06, S06 and M14 sends one, different, new message every day (repeating their respective messages across all their respective transmissions that day). On rare occasions, M14 has been seen repeating S06's message of that day. S06 uses a faster pace than normal; M14 uses ICW modulation.

This network is believed to be transmitted from the area of Khabarovsk in the Russian Far East. The transmissions span over several hours during the daytime over the Pacific area, on frequencies that are compatible with propagation over it. The same set of frequencies is always used, all year round. This network transmits through the daytime from Monday to Friday, but doesn't transmit during at least these Russian holidays, and associated bridge holidays:

• All days from January 1 to January 8 inclusive
• February 23 (Defender of the Fatherland Day)
• March 8 (Women's Day)
• May 1 (Labor Day)
• May 9 (Victory Day)
• June 12 (Russia Day)
• November 4 (Unity Day)

Moreover, this network doesn't follow some operational habits of this family, such as next-day message retransmission scheduling, or occasional slight frequency changes to avoid interfering signals (in particular for S06 ID 480, transmitting in broadcast bands); as well, F06 ID 60146 diverges from normal F06 metadata behaviors, and its headers suggest atypical message encryption.

Another remarkable trait of this network at least since 2021, is its very sloppy operations, and frequent mishaps and mistakes. Too often, transmissions suffer from late starts, callup mistakes, dozens of seconds of silence after the callup and before the preamble and message follow, wrong group counts or serial numbers in the headers, wrong messages sent, missing 00000 outro groups, or transmissions simply not happening at all; tuning errors or forgetting to retune to the next frequency between repeats, digital modem setting errors such as wrong FSK shift or Baud rate, M14 using FSK-CW or inverted ICW instead of ICW; and transmitter issues such as signal suffering from cutting in and out or failing prematurely, weak power, or distortion - this facility apparently operates several transmitters, one of which suffers from severely audible distortion. S06 may be transmitted using either H3E or J3E USB mode, contrary to the Russian 6 all-H3E voice habit.

Overall, the specificities of this network, including its seemingly noncritical nature, and combined with the amount and spread of the traffic, could point to an unknown particular purpose for it, with possibilities ranging from some kind of utility broadcast network, to dummy operations.

History

The history of this network is marked by a previous period of activity, prior to March 2019 and going back at least several years before that. It used to follow a similar but different schedule, more streamlined with less repeat transmissions, and using different frequencies:

Former schedule until March 2019

The network also followed additional particular habits. Foremost, messages always used the same group counts: 245 for digital modes F01 and F06, and either 50, 55 or 60 for analog modes S06 and M14. S06 and M14 followed particular rules for repeating digits in their message ID header field, and F06 ID 60146 featured no serial-GC postamble.

Starting on March 12, 2019, it was noticed that the network's habits had started to change: messages with slightly different group counts than normal were being sent, and message ID digit rules were relaxed. Then two weeks later, all transmissions on this network stopped: the last transmissions were observed on March 26, 2019.

However, from March 2021 on, this network was progressively rediscovered: F06 ID 60146 transmissions were first observed again, then others from there. The network's general structure was still the same, but it used different frequencies, and featured more typical transmission repeat slots, yet as were never observed on the network before: three transmissions spaced by 10 minutes for digital modes, and one repeat 20 minutes afterwards for analog modes. The restarted network picked up the new changed habits from its last days in 2019, and also saw new changes, such as F06 ID 60146 gaining a more typical serial-GC postamble.

It is unclear when this network's activity actually restarted, or whether it was all restarted as a whole at the same time, due to monitoring challenges and the new frequencies it used - some widely different from what could be expected, several MHz higher or lower than in the network's previous iteration. TDoA multilateration at that time allowed to tentatively locate the transmission site near Khabarovsk, which is consistent with observations prior to 2019 and was probably its location all along.

In April 2021, during a few days, this network briefly featured transmissions of F06 ID 70103 instead of 60146, as well as appearances of S06 ID 105 and M14 ID 105 (rediscovery was still partial at the time). ID 70103 is believed to correspond to Havana, Cuba as a recipient; the transmissions were indeed operated on frequencies up to several MHz higher than those normally scheduled, which supports a temporary change of target further away from Khabarovsk.