Editor Note: After the first of the new U.S. government fiscal year (1 Oct 2004), Ron Perron intercepted communications on the HF-GCS system which indicated that there have been changes to the Zulu Net. It is unknown at this time whether frequencies and designators have changed or just designators. I should also note that this network is no were near as robust in traffic as it was several years ago. Some have sid privately they believe that this is due to the E-6B platform communication suite being updated for the Looking Glass mission. It is quite eveident that they no longer have to rely on the HF network for communications. As always reports and observations are welcomed by those that monitor this system.Frequency/Designator Matrix (USB/frequencies in kHz)
Z100 3068.0
Z105 3116.0
Z110 3134.0 (tentative)
Z115 3143.0
Z120 3295.0
Z124 Unknown
Z125 4495.0
Z130 4472.0
Z135 4745.0
Z140 5026.0
Z145 5705.0
Z150 5800.0
Z155 5875.0
Z160 6715.0
Z165 6757.0
Z170 7831.0
Z174 Unknown
Z175 9016.0
Z180 9057.0
Z185 9809.0
Z190 10204.0
Z195 Unknown
Z200 11181.0
Z205 11494.0
Z210 11229.0
Z211 12070.0
Z215 13242.0
Z220 13245.0
Z225 13907.0
Z230 15046.0
Z235 15094.0
Z240 15097.0
Z245 Unknown
Z250 15962.0
Z255 17973.0
Z260 18006.0
Z265 18024.0
Z270 18027.0
Z275 18046.0 (tentative)
Z280 18387.0
Z285 Unknown
Z290 19665.0
Z295 19755.0
Z300 20167.0
Z305 20407.0
Z310 23337.0
Z315 23872.0
Z320 24828.0 (tentative)
Z325 24978.0 (tentative)
Z330 26532.0 (tentative)
Z335 26859.0
Z340 Unknown
Z345 Unknown
Z350 Unknown
Note: At 1805 UTC on December 16, 2003, monitored female opertor using a tactical call sign calling other tactical calls and IDed the frequency as Z-280/Z-230. A frequency, 7992.0 kHz was uncovered by Jeff Haverlah in Texas during a USSTRATCOM exercise on June 25, 2003. The frequency was being used by airborne command post participating in a STRATCOM communications exercise. No designator was monitored. Other notes on USSTRATCOM related communications / frequencies courtesy of Jeff Haverlah.
11244.0 kHz
This frequency is a special HF-GCS discrete that is used by *every* named HF-GCS station for Emergency Action Messages (EAM) and FOXTROT broadcast. In fact, it has been described as the "broadcast" frequency. Stations here do not respond to MAINSAIL general calls on this frequency.
This frequency is guarded by the Nightwatch 01 (US Air Force E-4 National Airborne Operations Center or NAOC) station (which uses daily changing callsign aliases) and is paired with 8992.0 kHz.
This frequency is used by the apparent USSTRATCOM Looking Glass mission aircraft for daily EAM transmissions at any time, and used for repeat EAM transmissions at H+25/H+55 mostly during North American daylight hours (and at any part of the day during exercises). Paired with 8992.0 kHz. Also guarded by the Glass mission and other U.S. Navy E-6 TACAMO aircraft when active.
The primary mission of the Looking Glass aircraft is the ability to command, control, and communicate with its nuclear forces. Its highly-trained crew and staff ensure there is always an aircraft ready to direct bombers and missiles from the air should ground-based command centers become inoperable. Looking Glass guarantees that U.S. strategic forces will act only in the precise manner dictated by the president. On Oct. 1, 1998 the Navy's E-6B Mercury aircraft replaced the USAF EC-135 in the Looking Glass mission.
Used by possible tanker aircraft (maybe on their SIOP mission) passing 4-element groups to "SkyMaster" (NAOC and TACAMO aircraft) during exercises and paired with 8992.0 kHz. The four element groups have been called "TID traffic" by SKYMASTER aircraft.
Used by other U.S. government stations (i.e. Federal Emergency Management Agency-FEMA, etc) including the static call "Blue Grass" (Mt. Weather, Virginia) as a frequency to pass "Hotel" messages. These messages are passed to each other and to the NAOC aircraft (using an alias separate from that particular day's callsign). This activity is usually during the third week of each month, is not paired with 8992.0 kHz, and many of the station's use callsigns begin with the letter "A" (i.e. Axle Rod, Army Ruler, etc).
Units here always identify the frequency as 11244.0 kHz and not with a tactical designator.
6697.0 kHz
This frequency is used by the TACAMO aircraft for daily evening/night (North America) EAM transmissions during the following time slots:
H+07/H+37 by a TACAMO LANT aircraft
H+14/H+44 by a TACAMO PAC aircraft
EAMs have been heard at any time during initial broadcast, simulcast on 8992.0, 11244.0 and on the USSTRATCOM Zulu net frequencies above.
This frequencies is also used by possible TACAMO aircraft to communicate with trigraph identifier stations during exercises (usually to receive 3-element group traffic from these trigraph stations.)
Also is used 24-hours a day by the United Kingdom's station MKL and their trigraphs (many of these thought to be Nimrod aircraft).
13155.0 kHz
This frequency is used by the TACAMO aircraft for daily daytime (North America) EAM transmissions during the following time slots:
H+07/H+37 by a TACAMO LANT aircraft
H+14/H+44 by a TACAMO PAC aircraft
EAMs have been heard at any time during initial broadcast, simulcast on 8992.0, 11244.0 and on the USSTRATCOM Zulu net frequencies above.
The activity on this frequency apparently moved here from 11267.0 kHz a few years ago. 11267.0 now seems to be quiet probably indicating that it is no longer used for this purpose.
Other U.S. Navy frequencies heard recently with EAM broadcasts by Jeff Haverlah and ye ole blog editor:
4515.0 4848.0 5680.0 6512.0 6666.0 6686.0 6720.0 6724.0 6778.0 6833.0 6903.0 7501.0 7589.0 8020.0 8971.0 9007.0 9010.0 9036.0 9283.0 10515.5 10805.0 10994.0 11187.0 11255.0 11271.0 13155.0 14698.0 15038.0 15049.0 16117.0 kHz
These and other old U.S. Navy HF HICOM (High Command) frequencies have been active in past with heavy EAM traffic. See HF-GCS post on this blogspot about the demise of the HF HICOM network (absorbed into the HF-GCS network).
