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SJD · Ultrasonic microphone jammer
Ultrasonic Microphone Jammer with Expandable Modules
A portable ultrasonic system for conversation privacy, with an included add-on module and support for up to four external ultrasonic units. Use ultrasound alone or add audible noise when needed.
- Ultrasonic microphone interference with optional audible noise.
- One additional ultrasonic module supplied.
- Supports up to four additional ultrasonic modules.
- Built-in rechargeable lithium battery: approximately 4–5 hours under ideal conditions; actual runtime varies with use.
Product code: SJD
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Product overview
Portable Privacy. Expandable Coverage.
Ultrasound or Combined Audio
Use ultrasonic output alone or add audible noise through the main unit’s separately controlled speaker.
Up to Four Add-On Modules
One ultrasonic module is supplied. Up to four additional units can be connected using an audio splitter.
Rechargeable Main Unit
The main unit weighs 0.3 kg including its battery. Runtime is approximately 4–5 hours under ideal conditions and varies with use.
Product details
Full description
Ultrasonic Interference for Microphone Privacy
SJD generates an ultrasonic signal using a proprietary algorithm to interfere with susceptible microphones in phones, voice recorders, and listening devices. It is intended for confidential meetings, interviews, and private business discussions.
Ultrasound-only mode is described for room and phone microphones. A separately controlled speaker adds audible noise across the speech-frequency range; the source recommends this combined mode for analog and laser-microphone scenarios. Results depend on the microphone, placement, and environment.
A Portable Main Unit with External Modules
The main unit has a built-in rechargeable lithium battery and supports mains operation through its power supply. Battery runtime is approximately 4–5 hours under ideal conditions. Actual runtime varies with use.
One additional ultrasonic module is included. Modules connect using a supplied jack-to-jack cable; an audio splitter supports up to four add-on units. Each external module requires its own supplied power adapter and does not run from the main unit’s battery.
Technical specifications
| Dimensions | 170 × 95 × 31 mm |
|---|---|
| Weight | 0.3 kg, including battery |
| Power input | 12–15 V; mains operation via power supply (220 V mains stated in the description) |
| Current draw | 0.35 A |
| Typical maximum range | 7 m |
| Typical effective range | 2 m |
| SPL at 1 m | 120 dB, as specified |
| Battery | Built-in rechargeable lithium battery |
| Battery rating | Source lists 1200 mA; capacity unit requires confirmation |
| Battery runtime | Approximately 4–5 hours under ideal conditions. Actual runtime varies with use. |
| Emission pattern | 30° overall; source describes 15° from the emission axis, with a varying pattern |
| Audio modes | Ultrasound only, or ultrasound plus audible noise with separate volume control |
| Dimensions | 95 × 55 × 23 mm |
|---|---|
| Weight | 0.08 kg |
| Power input | 12 V, using its own supplied adapter |
| Current draw | 0.25 A |
| SPL at 1 m | 120 dB, as specified |
| Included module | 1 additional ultrasonic unit |
| Expansion | Up to 4 additional ultrasonic modules via an audio splitter |
| Connection | Supplied jack-to-jack cable |
Applications and setup
Confidential Meetings and Interviews
Intended for business meetings, private conversations, and interviews where microphone recording is a concern. The source recommends facing the main transducers toward the suspected microphone location at less than 2 meters, with the add-on positioned laterally at approximately 1 meter.
Room reflections and microphone characteristics affect performance. Assess the setup in the intended space; coverage should not be treated as a guaranteed room-wide area.
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