CIS OFDM-121
 | |
|---|---|
| Frequencies | 4.454 MHz,20.866 MHz |
| Frequency Range | 4.454 MHz - 20.866 MHz |
| Mode | USB |
| Modulation | QPSK,OFDM |
| ACF | — |
| Emission Designator | — |
| Bandwidth | 3.1 kHz,2.7 kHz |
| Location | Russia |
| Short Description |
CIS OFDM-121 is an OFDM mode that uses OFDM bursts with 121 channels, spaced by two QPSK-like bursts. Not all of the 121 available channels of OFDM bursts are used and it's possible to note a different arrangement of the channels in different days. |
| I/Q Raw Recording | Download file |
| Audio Sample | |
CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 is an OFDMOrthogonal Frequency-Division Multiplexing mode that uses OFDMOrthogonal Frequency-Division Multiplexing bursts with 121 channels, spaced by two QPSKQuadrature Phase-Shift Keying (2 bits per symbol)-like bursts. Not all of the 121 available channels of OFDMOrthogonal Frequency-Division Multiplexing bursts are used and it's possible to note a different arrangement of the channels in different days.
Sometimes CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 transmission has only QPSKQuadrature Phase-Shift Keying (2 bits per symbol)-like bursts without OFDMOrthogonal Frequency-Division Multiplexing bursts, in such cases the QPSKQuadrature Phase-Shift Keying (2 bits per symbol)-like bursts are being transmitted in pairs (two QPSKQuadrature Phase-Shift Keying (2 bits per symbol)-like bursts, transmitted one after another), similar to regular transmission, the timing between transmission of each pair might be the same as during normal transmission with OFDMOrthogonal Frequency-Division Multiplexing bursts (long-spaced idle) or shorter (short-spaced idle). The transmissions without OFDMOrthogonal Frequency-Division Multiplexing bursts could mean that no traffic is being sent and CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 is in an idle state.
It was noticed that regular transmission (with OFDMOrthogonal Frequency-Division Multiplexing bursts) sometimes can have gaps - no OFDMOrthogonal Frequency-Division Multiplexing burst is being transmitted, despite OFDMOrthogonal Frequency-Division Multiplexing bursts were transmitted before and after the gap. There might be several gaps during the transmission, but in that case there should be at least one OFDMOrthogonal Frequency-Division Multiplexing burst before and after each gap (there might be two gaps in a row, but that's very rare). Sometimes QPSKQuadrature Phase-Shift Keying (2 bits per symbol)-like bursts might be transmitted one after another not in pairs up to 15 bursts in a row.
The origin of the signal is assumed to be Moscow, Russia.
Samples[edit]
Long signal recordings (USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)):
CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 regular transmission with OFDMOrthogonal Frequency-Division Multiplexing bursts (USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)):
CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 idle state (USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)):
Pairs of PSK4-like bursts with short transmission timing
Pairs of PSK4-like bursts with long transmission timing
Unknown PSK4-like repetitions (USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)):
Repetitions of eight pairs of PSK4-like bursts on 20.386 MHzMegaHertz (MHz) 10^6 Hz
Transition from "sounding mode" to regular transmission on 20.386 MHzMegaHertz (MHz) 10^6 Hz
Frequencies[edit]
The signal was noticed on frequencies from 4.454 MHzMegaHertz (MHz) 10^6 Hz up to 20.866 MHzMegaHertz (MHz) 10^6 Hz.
List of frequencies:
| Frequency | Verification |
|---|---|
| 20.866 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 20.392 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 20.390 MHzMegaHertz (MHz) 10^6 Hz | Observed one time. |
| 20.388 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 20.386 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 20.382 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 20.380 MHzMegaHertz (MHz) 10^6 Hz | Observed one time. |
| 19.870 MHzMegaHertz (MHz) 10^6 Hz | Observed one time. |
| 19.235 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 18.262 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 16.556 MHzMegaHertz (MHz) 10^6 Hz | Observed one time. |
| 14.468 MHzMegaHertz (MHz) 10^6 Hz | Observed one time. |
| 14.462 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 13.382 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. Observed by at least two people at different time and recieved in different locations |
| 11.087 MHzMegaHertz (MHz) 10^6 Hz | Observed one time. |
| 10.843 MHzMegaHertz (MHz) 10^6 Hz | Observed one time. |
| 9.240 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 9.077 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 8.071 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 6.878 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 5.112 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. |
| 4.454 MHzMegaHertz (MHz) 10^6 Hz | Observed several times. Observed by at least two people at different time and recieved in different locations |
Sometimes the frequency of transmission can suddenly change onto nearby frequency within 20 kHzKiloHertz (kHz) 10^3 Hz, but such hops are presumably rare.
It was noticed that CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 transmitted eight repetitions in idle state (eight pairs of PSK4-like bursts) on several frequencies across HFHigh Frequency (3-30 MHz) spectrum, one after another, from the lowest frequency to the highest, and then again and again for at least an hour and a half. It may be assumed that this is a sounding across several channels.
Video Examples[edit]
- CIS OFDM-121
- 4454 kHz 2400Bd PSK OFDM, Rus Diplo
- https://drive.google.com/file/d/1xGS-7eF0ZV60Is9XpsXYsA7kQhID2WRm/view?usp=sharing
Additional Links[edit]
Additional Images[edit]
CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 on 20.386 MHzMegaHertz (MHz) 10^6 Hz
CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 on 20.386 MHzMegaHertz (MHz) 10^6 Hz
CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 on 20.866 MHzMegaHertz (MHz) 10^6 Hz (up close)
CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 up close
CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 sounding in short-spaced idle state on 9.077 MHzMegaHertz (MHz) 10^6 Hz
CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 transmission hop from 20.386 MHzMegaHertz (MHz) 10^6 Hz to 20.390 MHzMegaHertz (MHz) 10^6 Hz
CISCommonwealth of Independent States (CIS), the former Soviet Republic OFDMOrthogonal Frequency-Division Multiplexing-121 on 20380 kHzKiloHertz (kHz) 10^3 Hz, with some selective fading
