Iranian number station

7910kHz USB: A New Signal of Interest for Shortwave Enthusiasts

Shortwave listeners across Europe have recently reported unusual activity on 7910 kHz USB, raising the possibility that a new Iranian numbers station may have appeared on the HF spectrum. While still unconfirmed, the signal’s characteristics, propagation behavior, and reception reports strongly suggest a Middle Eastern origin, making it a compelling subject for radio amateurs and HF monitoring enthusiasts.

The first logs of the 7910 kHz transmission emerged in early 2026, when listeners captured short voice messages consisting of structured numeric sequences. A recording published on YouTube documents a reception from France on March 1, 2026 at 18:11 UTC, identifying the signal as an “Iranian Number Station (Unconfirmed)” and noting a probable 10 kW transmitter located in Iran.

At the moment, the ENIGMA2000 group has not yet released a bulletin, and no Enigma designation exists. The transmission uses USB modulation, a choice consistent with modern numbers stations and military HF communications, offering better clarity and reduced detectability compared to AM.

Signal Characteristics Noted by SWLs

Radio amateurs monitoring the frequency have reported several recurring traits:

• Male voice, possibly synthetic or pre‑recorded
• Numeric groups delivered with consistent pacing
• Short, irregular bursts, typical of operational traffic
• Evening activity, matching Middle Eastern NVIS and long-path propagation windows
• Clear audio, suggesting a modern, well-maintained transmitter

These features align with known Iranian HF communication patterns, which often rely on structured voice messages for secure, one‑time‑pad‑based exchanges.

Why the Signal Is Likely Iranian

Although no official confirmation exists, several technical and propagation clues point toward Iran:

• Strongest reception occurs in Southern and Central Europe, consistent with a Middle Eastern source.
• Iran has a documented history of covert HF voice transmissions, including coded numeric messages.
• The 7.9 MHz region is commonly used for regional military and diplomatic communications in the Middle East.
• The cadence and timbre of the voice resemble other Iranian utility transmissions previously logged by the SWL community.

The YouTube recording explicitly labels the signal as Iranian and notes the likely transmitter location.

Why 7910 kHz Matters for HF Monitoring

For radio amateurs, 7910 kHz is an intriguing frequency for several reasons:

• It sits outside major broadcast bands, reducing interference.
• It offers stable nighttime propagation toward Europe.
• It is commonly used for utility, military, and diplomatic traffic.
• It is accessible even with modest equipment, making it ideal for SWL monitoring.

The fact that a portable receiver with a telescopic antenna successfully captured the signal in France highlights its significant transmission power and reach.

Recent Logs and Community Interest

Reception reports have surfaced from:

• Italy and France — clear USB reception
• Central Europe — intermittent but identifiable signals
• KiwiSDR receivers — consistent evening detections

The growing number of logs suggests that the station is not a one‑off event but part of a repeatable transmission pattern.

Technical Hypotheses from the Amateur Community

Radio amateurs analyzing the signal have proposed several possibilities:

• A new Iranian intelligence numbers station
• A military or diplomatic HF link using coded voice messages
• A regional encrypted communication channel activated due to geopolitical tensions

While speculative, these interpretations are consistent with historical patterns: HF coded transmissions often increase during periods of regional instability.

What Radio Amateurs Should Monitor Next

To better understand the nature of the 7910 kHz signal, experienced listeners are focusing on:

• Identifying message structure (3‑digit, 4‑digit, or 5‑digit groups)
• Tracking transmission schedules across multiple days
• Comparing voice samples with known Iranian HF signals
• Using direction‑finding (DF) techniques to triangulate the source
• Logging signal strength variations to estimate transmitter power

As more data becomes available, the 7910 kHz signal may soon be formally classified within the global catalog of numbers stations.