Last month was no exception. At the end of October, a signal was heard around the world on 6985 KHZ. It consisted of a mysterious warbling tone that sounded very much like a jammer. The signal stayed on 24 hours a day for about three days, starting on the 28th of October and ending on 31 October. Monitors all over the globe heard it, with listeners in eastern North America and Europe having strong (s9 or better) signals.

The purpose of the signal was as unclear as the transmitter location. It was speculated that the good signal strengths were due to the signal being transmitted from a satellite. It could have also been due to a transmitter putting out an incredibly high amount of power. HAARP (High-frequency Active Auroral Research Project) was considered as another possibility, however the HAARP facilities have been off the air for some time. The jammer theory was still a possible explanation for the signal, but was highly unlikely due to the fact that no signal was ever heard being jammed.

A possible explanation came on 31 October at 1900 UTC when the warbling signal stopped and was replaced by CW sending the callsign REA4 and a short 5F message. After the 5F groups, REA4 K was sent and was replaced by the warble. Similar transmissions occurred at 2140 and 2240 UTC. The signal disappeared not too long after and hasn't been heard since.

If the callsign is valid, the signal would have a Russian origin. It would appear that the warbling signal was some sort of a channel marker used to mark the frequency until time to send the messages. The format is very similar to the Single-Letter High Frequency Markers (SLHFM's) that continuously repeat a single letter in Morse code. My guess as to the user would be the Russian military, probably navy. Some of the messages sent by SLHFM's have been prefaced by the callsign RMP, which belongs to Russian Naval headquarters in Moscow. The strong signal strengths heard in Europe and eastern North America could be due to using a high-power transmitter located near the arctic in northern Russia. The messages could have been sent to numerous receiving stations spread out over a wide area such as ships.

This signal had the utility monitoring community intrigued for a couple days, then disappeared. I hope it comes back.

Now let's take a look at some loggings:
5435 - Unid high-speed data burst xsmissions at 0550, also on 6353. (TS)
6840//9130 - EZI, Mossad/E10 in USB at 0100 w/ (40)HBFVI. (JM)
6985 - Unid warbling signal in USB at 0704, sounds like an alarm siren. (TS)
8060 - OTH radar w/ CW "O" at 0820. (TS)
8137 - Cuban CW cut # stn at 0816. (TS)
8190 - CW stn at 0702 w/ 5F msgs for 127 & 801, signed down w/ 000. (TS)
8300 - "New Star" YL/CC 4F msg in AM at 0801. (TS)
10046 - 4XZ, M22 in CW at 0100 in tfc. (JM)
10248//12075//14931 - 8BY, M16 in CW from 0145-0200 rptng 057/532. (JM)
12475 - Unid stn K6 in CW at 1456 wking ZJ w/ 5F msg in cut #'s (1-0=AU34567DNT). (TS)
16303 - US military SIGINT operator training station in Sitor-B, ASCII 75/170, & CW w/ various coded msgs. (TS)
18086 - Unid 8-channel digital signal in USB at 2321, sounded like running water. (TS)
22108 - E3a in USB at 0000 rptg 38234. (JM)

Contributors: JM - John Maky, AR; TS - Tom Sevart, KS.

I want to wish all my readers a happy holiday season and see you next year.