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  • Regular price $419.99


The surveillance card is our newest Covert Audio Surveillance Transmitter, with an integrated PCB trace antenna which has been designed in line with the board. This transmitter utilizes 0201 SMD components, significantly reducing inductance and resistance throughout, this offers excellent signal and microphone sensitivity.

A very small Knowles omnidirectional microphone offers excellent audio pickup, a very slim profile throughout, this transmitter measures slightly smaller than a business card.

This is a permanent, always-on "hot-microphone", once the batteries are inserted the CardTX will begin live transmission of ambient and surrounding audio without interruption on the Ultra High-Frequency band for 12 continuous hours.

The CardTX will broadcast audio over a distance of 200-500 meters in a cluttered urban environment, up to 700 metres with LOS, through concrete, drywall and thick bush to any UHF receiver, it operates on two 7.9mm 1.55V button cell batteries

Use this transmitter to remotely listen to an area of interest that requires discreet acoustic monitoring. Because of its slim profile, this transmitter is capable of covert placement using double-sided adhesive (Alien tape or 3M works best).

We recommend any handheld UHF receiver capable of tuning into the 400MHz-434MHz range, this is a standard range in most UHF receivers. Your CardTX will arrive with its specific Tx/Rx frequency noted on its back.

Power Supply 2x 7.9mm 1.55V Button Cells (3v) : ~12 Hrs Of Continuous Operation.
Dimensions 3.3 “ x 2 “ X .8mm

100Hz ~ 20kHz KNOWLES: Analog Microphone Electret Condenser. Directional Characteristic: Omni-Directional
Sensitivity: -7.0 ±4 (0 dB = fs/Pa@1kHz).
Signal to Noise Ratio: 78 dB Typ. at 1kHz.
Max Input Sound Level: 101 dB SPL Typ.

Weight Without Batteries: 11g | With Batteries: 11.3g
Output (RF) power  14mW
Antenna Integrated PCB Trace Antenna
Frequency Range

430MHz-439 MHz, 2.5 kHz step.

Effective Range 15m From Centre. 
Stability  Highly Stable. Crystal Referenced Phase-Locked Loop.
Crystal 00k/ASK Data Transmitter.

Obsidian's transmitters are easily paired with any compact hand-held transceiver. Any Two-Way UHF Radio will work.

In order to maintain its longevity, the CardTX comes potted with a compound that seals all onboard components. Only the microphone and the battery retainers are accessible and made visible.

Please check all local laws prior to deployment, or have permission to use.