Wednesday, December 08, 2021

Russian Mystery Military Station - The Air Horn

Transmitting on 3510 kHz. the Russian Air Horn is another Western Military District frequency marker that was first heard in Feb 2017. This station does not send any message traffic, instead, this station is used for testing technical equipment and other audio tests. Video of this station on our YT channel  at

More Russian Mysterious Military Stations on HF

Since I posted my earlier article on Russian Mysterious Military HF Stations I have added two more Russians to my YouTube video channel. First is The Alarm on 4770 kHz and you can view it at The second I just posted to the channel is The Goose on 3243 kHz. That video is at I have a few more to post in this series and you can follow that on either my Twitter feed or by subscribing to my YouTube channel where I am building a library of videos for non-broadcast stations aka Utes in HF and above.

Tuesday, December 07, 2021

Another Russian Mystery Military Station - The Alarm

Have just posted a video of another Russian HF military mystery station transmitting on 4770 kHz USB to my YouTube "From the static channel.  Like the rest of its Ruskie mystery mil cousins, no idea what it is used for. See video at be sure to subscribe to our YT channel as more video is on the way.

The World of Strange Military Stations - The Russians

Note: This column originally appeared in the January 2021 issue of Spectrum Monitor magazine. Copyright 2021 by the author and Teak Publishing. The full column is available for $3 in pdf format at one-year sub is only US$24.

Mysteries are always fun. In fact, I am a huge fan of the various Masterpiece Mystery series on Sunday evenings broadcast on our local PBS station. My favorite is Masterpiece’s Endeavor. They even did a show that featured a shortwave radio spy numbers plot in Season 5, Episode 5. You got to love a good mystery. But there are even more mysteries in the world of military communications than even Inspector Endeavor Morse can solve on an episode of Masterpiece’s Endeavor

Probably no other country has as many as Russia. Yes, our old Cold War enemy still has some interesting military stations on the air that qualify as bona fide mysteries. What are they and where are they located? What are they broadcasting? Why are they even on the air?

Maybe we need to call in Endeavor’s partner Inspector Thursday to help us explore some of these Milcom Mysteries. Sorry, I could not resist using the analogy; I like the show.

The Buzzer (Enigma S28)

A Russian military station, nicknamed by radio hobbyists "The Buzzer," is an HF station that broadcasts on a frequency of 4625.0 kHz. First reported in the 1970s, the station transmits using AM with a suppressed lower sideband (USB modulation), but it has also used full double-sideband AM. The signal consists of a short, monotonous buzzer-sounding tone that repeats at a rate of approximately 21 to 30 plus tones per minute, 24 hours per day. 

Sometimes the buzzing sound is interrupted, and a voice message in Russian is broadcast by either a male or female announcer. These messages are usually transmitted live and they do follow a fixed format. Most of the station’s messages are sent weekdays during local daytime (Moscow Time UTC+3).

The traffic sent on this station is simultaneously transmitted in Morse code on multiple other frequencies. Because this station uses old equipment that is prone to failure, channel separation issues have occasionally allowed those Morse code simulcasts to be heard on the voice station.

During these live voice messages, distant conversations and other background noises have frequently been heard behind the buzzer. Some suggest that this means the buzzing tones are not generated internally but are transmitted from a device placed behind a live and constantly open microphone.

Until 2010, the station identified itself as UVB-76, which was a bad mistranscription of the actual call sign UZB76, and it is still often referred to by the media and others by this name. Since then the station operators have used a wide variety of call signs and call words to identify the station.

Speculation over the purpose of this military-controlled station has quite honestly been all over the map. Everything from keeping military communication operators alert to a propagation/channel marker. One theory, described in a BBC article, stated that the tower was connected to the Russian 'Perimeter' missile system. The station was transmitting a “Dead Hand” signal that would trigger a nuclear retaliatory response if the signal is interrupted due to a nuclear attack against Russia. Since the station has been noted off the air at various times in the past, I think we can pretty much put that theory to bed.

There are reports that The Buzzer is controlled by the Russian Sudak communication hub ("Agalatovo"). It is widely believed to have several transmitter sites, which are switched between often. Some of the identified ones include the 69th Communication Hub ("Iskra") and the 60th Communication Hub ("Irtysh"). This station is a Russian military command network that serves the Western Military District. 

The Buzzer is not the only Russian military station mystery. There are two other Russian stations that follow a similar format, nicknamed “The Pip” and “The Squeaky Wheel”. Like the Buzzer, these stations transmit a signature sound that is repeated constantly but is occasionally interrupted to relay coded voice messages.

The Pip (Enigma S30)

Nicknamed “The Pip,” by radio listeners, this Russian military station broadcasts on 5448.0 kHz (day), and 3756.0 kHz (night). It broadcasts continuous short, repeated beeps at a rate of around 50 per minute. Like the Buzzer described above, the beep signal is occasionally interrupted by voice messages in Russian sent by both male and female announcers. The Pip has been active since around 1985 when its distinctive beeping sound was first recorded by listeners. The station's format resembles, in many ways, that of its presumed sister station “The Buzzer.” 

The times at which the station switches from the day to the night frequency or vice versa are changed over the course of the year, presumably to match the changing lengths of day and night. Higher frequencies have better propagation characteristics during the day, while lower frequencies do better in darkness.

The website reports that The Pip usually multicasts traffic, without the channel marker, on either 6913.0, 6922.0, or 7056.0 kHz during daytime with 7126.0 kHz being observed as of December 2019, and on 3371.0 kHz during nighttime. Some of these frequencies also carry exclusive traffic. Transmissions on 6922.0 kHz sometimes leak conversations from within the radio room via an open microphone. Sound familiar?

Like the Buzzer, the purpose of The Pip is not known, although there are many hypotheses. It is often suggested that The Pip is part of a larger radio relay or control system that includes The Buzzer and The Squeaky Wheel stations, which both follow similar formats. 

In fact, activity on The Pip often used to be followed a few minutes later by a voice message on The Squeaky Wheel, suggesting that both were being operated by the same organization and shared the same purpose. On one occasion, The Pip's characteristic beeping sound could be heard in the background while a message was being transmitted on the Squeaky Wheel's frequency, which could indicate that both stations were even operated from within the same building or room. However, these activities have since ceased.

The Pip is transmitting from Rostov-on-Don, Russia. It is also a military command network that serves the Russian Southern Military District. 

Squeaky Wheel (Enigma S32)

The third of our mysterious Russian military stations are known as “The Squeaky Wheel,” another nickname given by the radio hobby community. From around 2000 until 2008 the station's attention tone was a high-pitched two-tone signal that vaguely resembled a squeaky wheel. From 2008 the channel marker changed to two different tones in a short sequence repeated with a short silent gap. This station transmits voice on 3828.0 kHz (nights) with CW on 3895.0 kHz, and 5473.0 kHz (day) voice with CW on 5361.0 kHz.

Since this station appears to be associated with the other two, we may have an indication the true mission of the stations by traffic that has been intercepted from the Squeaky Wheel. There have been several times that voice messages in the format of Russian Military Strategic Flash Messages have been reported by this station. 

The exact transmitter site is unknown but like the “Pip” it is thought to be near Rostov-on-Don, Russia, which would indicate a Southern Military District network station. It has been noted by some regular monitors of this station that the signal strength is not very good in Central Europe and the signal sometimes even disappears for days in the noise.

The Pip/Squeaky Wheel connection

There have been instances of transmission from Squeaky Wheel with clearly audible Pip channel marker in the background having been picked up by the operator's microphone. This implies that the Squeaky Wheel operator is clearly monitoring the Pip. As can be deduced from the complete lack of follow-on message from Pip after a Squeaky Wheel transmission and having never observed Squeaky Wheel channel marker bleeding into Pip transmissions, it seems that Pip does not need to monitor Squeaky Wheel.

Finally, reported that on May 9, 2019, the Squeaky Wheel accidentally began reading a message transmitted from Pip several minutes prior before the operator corrected herself and continued with the appropriate/correct message, definitively proving that Squeaky Wheel indeed copies transmissions from Pip.

Who or what are these stations?

Here is what we believe. Are they Russian? Yes. Are they military? Yes. In fact, based on the Russian military order of battle and who we think is transmitting these broadcasts it looks like we are dealing with some Russian army ground forces HF networks.

Several in our radio hobby believe that the HF radio presence of these Russian Ground Forces consists of many interconnected subnetworks and that the ones I have discussed here are just three of them. 

In these networks, the callsigns are made of either a word and 2 digits (in voice only), or a 4-character combination of letters and sometimes digits. A callsign may refer to either a single unit or a group of units. In some cases, some of the messaging appear to be relaying the same strategic flash messages used by the Russian Supreme High Command (Verkhovnoe glavnokomandovanie--VGK). Yes, the same organization I mentioned last month that sends out strategic submarine flash override messages in VLF and on various other HF radio frequencies.

Priyon,org has a list of Russian ground forces HF networks that you can explore at These include the following listed below:

Russian Southern Military District: The Pip (5448.0/3756.0 kHz), The Squeaky Wheel 
(5473.0/3828.0 kHz), Vega (5372.0 kHz), Baron-78 (3850.0/4940.0 kHz).

Russian Western Military District: The Buzzer (4625.0 kHz), D marker (5292.0 kHz), T 
marker (4182.0 kHz), The Air Horn (3510.0 kHz), The Goose (4310.0/3243.0 kHz), The 
Alarm (4770.0 kHz), and Katok-65 (4224.0/3218.5 kHz).

Given the proximity of the two areas to eastern Europe, these stations may be part of some early warning nets that are operated by the Russian army ground forces. Their purpose may be to sound the alarm of any potential attack by NATO/U.S. ground forces that threaten Mother Russia (Matushka Rosa). So maybe on the Russian side of the border, if these stations are any indication, Perestroika did not change everything within the Russian military and its posture towards the West.

The Single Letter CW Beacons (Enigma MX)

The Russian Army is not the only player with mystery stations in the HF spectrum. While they do not have cute radio hobbyist nicknames like the army stations do, the Russian Navy has operated a mysterious network of single-letter CW stations since the early 1960s.

My first exposure to these mysterious stations came from a book that was published by Tab in 1981 by the legendry radio monitor and author Harry Helms W5HLH (SK) titled How to tune the secret shortwave spectrum.

In 1978 Harry and several others noted a CW station sending the letter "W" continuously on 3584.0 kHz, in the 80-meter ham band. There was indirect evidence using greyline propagation techniques that this transmitter was in Cuba. He theorized that it may have had something to do with the Russian/Cuban military services. This started a chain of events that elevated the attention of the radio monitoring community to this  “W’ CW station and to other CW beacons in the HF spectrum like it.

In 1982 there were also reports, supposedly based on HF direction finding by the U.S. military, that a station was transmitting the CW letter "K" on 9043.0 kHz it was located near the city of Khabarovsk in the then USSR. This was reported again in 1984 by an anonymous source in the old SPEEDX Reference Guide, and to me by Donald W. Schimmel (SK), a Monitoring Times colleague, in private correspondence. 

Don also indicated that in 1986 the Federal Communications Commission (FCC) released the HF direction finding results for several single letter beacons or what he wanted them called “markers,” and all were DFed to locations in Russia. So in this column to honor Don’s wishes back then, I will call them what he wanted them known as – Single Letter HF Markers or SLHFM. You will probably see others still using the term beacons.

A few years later William (Bill) I Orr W6SAI (SK), in Popular Communications magazine, suggested that the "K" marker was, in fact, located at Petropavlovsk on the Russian Kamchatka Peninsula and the "U" markers were located somewhere along the Barents Sea coast, between Murmansk and Amderma.

Today these Single Letter HF Markers are still active nearly 60 years after their original discovery. My friend and fellow ute monitor Ary Boender, the driving force behind the UDXF/N&O, published definitive locations for most of these stations in 2006.

The single-letter HF markers can be classified into two groups, "cluster markers" and "solitary markers." It should be noted that a "P" marker exists in both groups. 

The Clusters

This group of radio markers with single-letter identifiers (C, D, M, S, P, A, M and K) have been regularly reported centered on 3594.0, 4558.0, 5154.0, 7039.0, 8495.0, 10872.0, 13528.0, 16332.0 and 20048.0 kHz. The term "cluster markers (beacons)" is frequently used for them, as they transmit in parallel on frequencies only 0.1 kHz apart. These beacons transmit only their single-letter identifier in standard Morse code and are located at Russian Naval Bases.

D  RCV Sevastopol, Ukraine  3593.7  4557.7  5153.7  7038.7  8494.7  10871.7  13527.7  
16331.7  20047.7

P  RMP Kaliningrad, Russia  3593.8  4557.8  5153.8  7038.8  8494.8  10871.8  13527.8  16331.8  20047.8

S  RIT Severomorsk, Russia  3593.9  4557.9  5153.9  7038.9  8494.9  10871.9  13527.9  16331.9  20047.9

C  RIW Moscow, Russia 3594.0  4558.0  5154.0  7039.0  8495.0  10872.0  13528.0  16332.0  20048.0

A  Astrakhan, Russia (tentative)  3595.1  4558.1  5154.1  7039.1  8495.1  10872.1  13528.1  16332.1  20048.1

F  RJS Vladivostok, Russia 3595.2  4558.2  5154.2  7039.2  8495.2  10872.2  13528.2  16332.2  20048.2 

K  RCC Petropavlovsk-Kamchatsky, Russia  5154.3  7039.3  8495.3  10872.3  13528.3  16332.3

M  RTS Magadan, Russia  4558.4  5154.4  7039.4  8495.4  10872.4  13528.4  16332.4  20048.4

Monitor reports in the Numbers and Oddities (N&O) bulletin have shown that some cluster markers (especially "F" and "M") have been transmitting on frequencies different from their regular frequencies for short periods.

The Solitaries

The second family of letter markers includes all of those that operate outside the clusters. For this reason, they are often called "solitary markers" or "solitaires". They also transmit their single-letter identifier in standard using Morse code.

A few solitary markers, like "R" on 4325.9 and 5465.9 kHz, operate exactly like the cluster beacons, sending only their single-letter identifier and nothing else.

Most of the solitaries, most notably "P" on various MF and HF frequencies, in addition to their single-letter identifier, send brief messages using high-speed CW or in an FSK digital mode. There is no evidence that the cluster marker "P" and the solitary marker "P" are directly related.

It was reported in Numbers and Oddities, issue 142, that a marker “C” transmitting on 8000 kHz also sent messages using it international call sign RIW, which is allocated to a Russian naval communication station in Khiva, Uzbekistan. 

There are also a few oddities transmitting signals with poor modulation and irregular timing, like the "V" marker listed below. The "P" marker transmissions also carry Russian Navy flash priority Morse code messages with the call signs RPM and RD.

Here is a known list of the solitaries recently reported to the UDXF forum.

R  Izhevsk (Ustinov), Russia  4325.9  5465.9

V  Khiva, Uzbekistan  3658.0  5141.0  5342.0 (irregular)  6430.7 (irregular)  6809.0  7027.5  8103.5  10202.0

P  Kaliningrad, Russia  420.0  583.0 (MW in December 2007)  3167.0  3291.0  3327.0  3699.5  3837.0  4031.0  4043.0  4079.0

C  RIW Khiva, Uzbekistan  8000.0

Who or what are these stations?

According to ENIGMA, these SLHFM stations are used by the Russian navy (especially its submarine branch) to find the most suitable radiofrequency for contact based on current radio propagation conditions.

The purpose of the letter beacons is not yet known with any certainty. Like their Russian Army counterparts, their many theories, but none is based on any documentary evidence. They have been postulated to be radio propagation beacons, channel markers, or beacons used in tracking satellites, or for civil defense purposes. Some stations of this family of stations, in particular the "U" beacon, have been implicated in deliberate jamming.