446 MHz Mosque Audio Link

@hayteekeys

HI, KINDLY READ THROUGH MY PROPOSAL I will design the PMR446 radio set around the SA818S-U: one transmitter and two receivers, all on the same frequency and CTCSS, with a dead-quiet standby path and PAM8403 speaker drive. MY APPROACH ✅ SA818S-U UART config (channel, CTCSS, squelch) so RX stays silent until a valid tone ✅ Mute/squelch into PAM8403 + 3 W / 4 Ω speaker, rotary volume and power switch ✅ USB-C 5 V in, 3.3 V LDO for the module ✅ KiCad/EasyEDA, JLCPCB-ready Gerbers; firmware to init the SA818S DELIVERABLES - Bench demo: 1 TX + 2 RX - Schematic + Gerbers - BOM with part numbers and India (LCSC/Robu/etc.) links - UART init firmware/code QUESTIONS 1. Exact PMR446 channel and CTCSS tone? 2. TX board same form factor as RX, or handheld/simple carrier? 3. KiCad or EasyEDA preference? Ready to start as soon as channel/CTCSS and enclosure size are confirmed.

@hamzazayyad

Hello, I saw your project for a 446 MHz wireless audio broadcast system for mosque sound, using SA818S-U modules, auto-VOX, CTCSS, AGC, and dedicated home receivers. I loved the practical end-to-end design and focus on silent standby and instant audio. What do you think if I develop the complete transmitter/receiver electronics, firmware, and KiCad schematics/PCB? I have 15+ years of experience in embedded systems, STM32/ESP32 firmware, RF module integration, audio electronics, PCB design, power supplies, and product prototyping. I can handle: • SA818S-U UART initialization and configuration • 446.0562 MHz / CTCSS setup and reliable TX/RX control • MAX9814 audio conditioning and automatic VOX detection • Hardware squelch/mute for truly silent receiver standby • PAM8403 audio amplifier and volume control • 5V/3.3V power design and protection • Complete KiCad schematic, PCB and JLCPCB-ready Gerbers • BOM with verified components and documentation • Bench prototype testing with 1 transmitter and 2 receivers I can also optimize the audio path for clear speech, fast VOX response, and minimal noise. I understand the importance of RF grounding, 50-ohm routing, connector/cable considerations, and reliable embedded control. I would be glad to review your requirements and turn them into a working prototype. Best regards, Hamza

@cesur135

As a seasoned Electrical Engineer with significant experience in developing and designing systems, I am uniquely qualified for your mosque audio link project. From wastewater treatment plants to water treatment automation, I have taken charge of writing complex system software, scada programming and project management - skills which directly align with your project's requirements. My expertise extends to process automation and HES projects where I've controlled varied systems on different SCADA platforms. I can confidently assure you that my extensive experience with collaborating on diverse industrial automation projects will be invaluable to your endeavor. Previous projects have seen me work with Honeywell DCS C200 and WinCC SCADA programs to closely monitor and control equipment. Moreover, in dealing with manufacturing chocolate machines, I gained valuable insights on precision, reliable circuitry that will be useful in the transmitter and receiver aspects of this project. Furthermore, I possess strong skills in circuit design (Devre Tasarımı), Electronics (Elektronik), and Embedded Systems (Gömülü Sistemler), talents which are necessary for successfully completing your project. Additionally, my proficiency in KiCad and EasyEDA will greatly expedite the schematic and PCB design phase. Given the chance, I'm confident that my knowledge base

@alluankit01

I don’t recommend bidding on this project. The client requires both hardware engineering and physical validation, including: • 1 transmitter + 2 receiver bench prototypes • Live clear-audio test video • 446 MHz RF design and antenna integration • Audio AGC/VOX and squelch circuitry • PCB schematic/layout and Gerbers • Verified Indian sourcing/BOM • SA818S UART firmware • Real RF/audio testing after assembly This does not fit a software-only/remote-design scope because final acceptance depends on physically assembled and demonstrated hardware. There is also a regulatory issue with the requested RF configuration. The proposed 1 W transmitter and external high-gain antenna should be reviewed against current Indian WPC/DoT requirements before any design is built. I would save this bid for embedded firmware, PCB/EDA design with client-side testing, UART/protocol work, or other projects where no physical prototype demonstration is required. Best regards Ankit

@caodx

Hello, I have strong experience in RF hardware, embedded systems, and PCB design, and I am very interested in this PMR446 wireless audio broadcast project. I have worked with STM32, ESP32, audio processing circuits, RF modules, and production-ready PCB designs for commercial products. For this project, I can design the complete transmitter and receiver hardware based on the SA818S-U module, including the MAX9814 microphone front-end with AGC, VOX activation, UART configuration, audio amplification, power management, and optimized RF layout. I can also implement reliable mute and squelch control to ensure the receiver remains completely silent during standby while providing fast activation when audio is detected. My deliverables include schematic design, PCB layout, BOM, Gerber files, manufacturing support, and firmware for module configuration and control. I focus on practical, manufacturable designs and thorough testing to ensure stable operation and good audio quality. I would be happy to discuss coverage requirements, antenna selection, and system optimization before starting. Best regards, Phuc Cao

@hexabitzprojects

Hi, This project is a strong match for my **16 years of R&D experience in embedded hardware, RF, audio electronics and PCB design**. I have completed RF/wireless embedded projects, custom PCBs, signal-conditioning circuits and audio-related electronics. I can develop the complete **SA818S-U transmitter + receiver system**, including UART configuration, 446 MHz/CTCSS setup, audio conditioning, automatic VOX, squelch/mute and PAM8403 amplification. For the transmitter, I can implement MAX9814 AGC/audio leveling, reliable VOX/PTT control, power protection and a properly designed 50Ω RF path. For the receiver, the priority will be **silent standby with no audible hiss/static** and fast, clean audio activation when the correct signal is received. I can design the PCBs in **KiCad/EasyEDA**, prepare manufacturing-ready Gerbers and BOM, develop the SA818 UART initialization firmware and perform bench testing with **1 transmitter + 2 receivers**. I will also review RF grounding, antenna/cable interface, power supply and EMC considerations, and verify the proposed operating frequency/configuration against applicable Indian regulations before finalizing the design. Deliverables include schematics, Gerbers, BOM with Indian sourcing, firmware/code and prototype demonstration. Best regards, **Subhash Suman** RF | Embedded | Audio | PCB Design **16 Years R&D Experience**

@WasiGFX

Dear Client, I can design and prototype this 446 MHz wireless mosque audio system with the SA818S-U, MAX9814 AGC/VOX, silent hardware squelch, PAM8403 amplifier, and 5V power design. I can provide the complete transmitter + 2-receiver prototype, clear test video, KiCad/EasyEDA schematics and Gerbers, verified BOM with Indian sourcing, and UART firmware for SA818S-U initialization. I can start with the transmitter/receiver circuit design and RF/audio testing, then move to the PCB-ready files and prototype.

@namitad27

Hi there, I am a hardware technician and embedded developer based in India, ready to design and prototype your 446 MHz wireless audio broadcast system. I understand the critical need for a dead-silent receiver during standby and a reliable Auto-VOX trigger from the Ahuja PA system. Here is my execution plan: Hardware Design: I will design the schematics and PCBs (via EasyEDA for seamless JLCPCB manufacturing). The Tx will feature the MAX9814 for AGC and SA818S-U (1W) with surge protection. The Rx will integrate the SA818S, hardware squelch, PAM8403 amp, and USB-C power delivery with AMS1117-3.3V regulation. Prototyping: I will utilize my micro-soldering and electronics troubleshooting skills to assemble the bench prototype (1 Tx + 2 Rx), ensuring perfect hardware squelch and pristine audio without hiss. Firmware & UART: I will apply my C programming and serial control protocol skills to write the initialization code configuring the SA818S modules (446.0562 MHz + 67.0 Hz CTCSS) via UART. Sourcing: Being located in India, I will provide a highly accurate BOM with verified local sourcing links for all components. I will deliver the working prototype video, Gerber files, BOM, and firmware code as requested. Let's discuss the schematic details to get started. Best regards, Prince Das