REA4 is the callsign of Russia's Long Range Aviation, and one of the callsigns used on its one-way Morse code strategic broadcast. It is present in both western and eastern Russia, transmitting simultaneously from Moscow and Khabarovsk.
The Moscow broadcast uses on-off keyed CW, with 100 Hz dots serving as a channel marker.
|5293 kHz||?||5293 kHz||4649 kHz
The Khabarovsk broadcast uses frequency-shift keyed CW with a shift of 1000 Hz, with 100 Bd reversals serving as a channel marker.
|10653 kHz||?||10653 kHz||10981 kHz
|5853 kHz||?||5853 kHz||6087 kHz
"Monolith" type messages
Like other strategic networks of the Russian military, REA4 airs "Monolith" type messages of the standard format. The callsigns used include 1QRF, 7XMF, JUE4, JZLB, MJUR, MSK7, PABA, HA57, L9XC, QMCK, RLO92, and REA4 itself.
REA4 transmits hourly weather bulletins at 40 minutes past. The format used is a variation of SYNOP.
Not all groups may be present in a given message. The time consists only of the hours; midnight is represented as "24", not "00"; the timezone given can range from UTC-2 to UTC+3, although UTC-1 is the most common. The temperature is given in degrees Celsius, and is encoded as a 4-digit value as follows: "0" or "1" for positive and negative values respectively, followed by the 2-digit temperature, and then by a single decimal as the last digit.
REA4 covers six different airfields using the IDs noted below. Log pages for traffic analysis are linked from each ID and air base information from each name.
On November 19th 2018 we have received traffic for a 7th ID, 23746, for which no airfield location has yet been pinpointed. On December 15th 2018 an 8th ID has appeared, 23767, we have not yet deduced to which airfield this ID belongs. These two previously unknown IDs oddly share their first three digits and transmit in the same timeframe as one another.
- 20069 (Soltsy-2)
- 22212 (Belaya)
- 23672 (Dyagilevo)
- 23746 (Unconfirmed)
- 23767 (Unconfirmed)
- 27627 (Engels-2)
- 62596 (Ukrainka)
- 73842 (Shaykovka)
A typical REA4 hourly weather bulletin with translation;
20100 99900 19150 27627 81997 21702 10014 21015 70300 82031 912//
20100 - 20th of the month at 10am, wind type in estimated
99900 - standard weather broadcast type
19150 - 19th of the month at 3pm, start of observation period
27627 - airfield identifier
81997 - manned weather station, weather group included, cloudbase above 2500m, visibility 10km
21702 - 2/8ths total cloud cover, 170° wind direction, 2m/s windspeed
10014 - +1.4°C temperature
21015 - -1.5°C dewpoint
70300 - clouds developing from previously clear skies
82031 - mid-level altocumulus translucidous and high-level cirrus fibratus
912// - observation made in 12th hour local time, minutes ommitted