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  • Regular price $300.00
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The BCTX is a discreet surveillance transmitter that features an integrated PCB trace antenna, designed to match the board's specifications. With its 0201 SMD components, it offers excellent signal quality and microphone sensitivity by minimizing inductance and resistance, BCTX is slightly smaller than a standard business card. 

This transmitter is now available with a new extremely sensitive KNOWLES microphone, and a new high-powered crystal generating 20mW of RF power, ensuring superior frequency stability and delivering enhanced audio sensitivity. For custom power options to extend the operating time, please feel free to contact us for further assistance.

As a permanent, always-on "hot-microphone," the BCTX initiates live transmission of ambient and surrounding audio immediately upon battery insertion. It operates seamlessly on the Ultra High-Frequency band for a continuous duration of 12 hours.

In a cluttered urban environment, the BCTX broadcasts audio over a range of 200-500 meters, extending up to 700 meters in Line-of-Sight (LOS) conditions. It effectively transmits audio through obstacles such as concrete, drywall, and dense vegetation. The transmitter operates on two 7.9mm 1.55V button cell batteries.

Utilize the BCTX for discrete acoustic monitoring in areas of interest. Due to its slim profile, the transmitter can be covertly placed using double-sided adhesive, such as Alien tape or 3M adhesive.

For optimal performance, we recommend using any handheld UHF receiver capable of tuning into the standard frequency range of 400MHz-434MHz, which is supported by most UHF receivers. Our recommended handheld receiver is the Baofeng UV-5R. Your BCTX will arrive with its specific Tx/Rx frequency clearly indicated on its back.

Power Supply Options

2x 7.9 mm Button Cells (1.55V) 392/384: 12 Hours Of Continuous Operation.

Dimensions 3.5″x 2″

CUI: 100 Hz ~ 20 kHz Analog Microphone Electret Condenser Omnidirectional (-42dB ±3dB @ 94dB SPL)

KNOWLES BJ-21590: 300 Hz ~ 5 kHz Analog Microphone Magnetic Omnidirectional (-75.5dB ±3dB @ 74dB SPL)

Weight 4g
Output (RF) power   20mW
Antenna Alpha Wire 8 in. Micro Coaxial Cable 38 AWG 
Frequency Range

433 MHz-436 MHz, 2.5 kHz step.

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

In order to maintain its longevity, the BCTX is potted with a compound that seals all onboard components, only the microphone and the battery terminal pads are accessible and made visible.

We can design for your needs. TINYTX has designed and manufactured hidden and covertly disguised audio surveillance transmitters for several client projects and applications. Contact us for turnkey solutions.

If you're seeking something even smaller and equally capable, the V3TX is an excellent option, measuring a mere 13.9mm x 19.4mm x 0.8mm.