CIS MFSK-16 XPB

CIS MFSK-16 XPB

Frequencies	10 MHz,20 MHz,4.4 MHz
Frequency Range	4.4 MHz - 20 MHz
Mode	USB
Modulation	MFSK
ACF	—
Emission Designator	—
Bandwidth	2.8 kHz
Location	Russia
Short Description	A digital mode used by Russian intelligence
I/Q Raw Recording	Download file
Audio Sample

Enigma designation XPB is a custom 16-tone MFSKMultiple Frequency Shift-Keying mode which is believed to be used by Russian intelligence.

The signal occupies about 2.8 kHzKiloHertz (kHz) 10^3 Hz of bandwidth, but the first tone is about 500 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). away from the designated transmission frequency, making the total bandwidth about 3.3 kHzKiloHertz (kHz) 10^3 Hz.

A 13-tone variant and slower transfer rate modes exist but it's not known if they use the same signal format or are used for the same purpose.

Frequencies

XPB transmissions occur on numerous frequencies between 10 MHzMegaHertz (MHz) 10^6 Hz and 20.1 MHzMegaHertz (MHz) 10^6 Hz. Frequencies between 4.4 MHzMegaHertz (MHz) 10^6 Hz and 10 MHzMegaHertz (MHz) 10^6 Hz have also been used, but it's not known if they are used since 2022.

Video Examples

• Video by Signal Phantom
• Video by OH8EFI

Additional Links

• XPB on Priyom.org, including schedule

Additional Images

Zoomed waterfall image XPB often looks like this if the waterfall is not carefully adjusted to reveal the individual MFSKMultiple Frequency Shift-Keying tones One or more tones are sometimes transmitted on the frequency before the actual XPB transmission begins Faint rattling signal can sometimes be detected before an XPB transmission begins. It may be caused by the transmitter idling and it isn't there after the transmission ends.