Ham Radio Digital Modes: COS Circuit Build (Ham Radio DIY)

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Published on September 24, 2025 2:03:38 PM ● Video Link: https://www.youtube.com/watch?v=dQeY9Dy-rWk

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We’ve reached the grand finale of the TOADs Digital Interface build series! 🎉 In this episode, I walk you through building the Carrier Operated Squelch (COS) circuit — the secret sauce that makes the entire interface come alive.

This project transforms any old radio into a modern digital modes machine with just a simple USB connection. Whether you’re into FT8, JS8Call, PSK31, or any other digital mode, this build will give you the tools to get on the air.

👉 If you missed the earlier videos in the series, check them out here:
• Part 1 – PTT Circuit    • Ham Radio Digital Modes: How a Tiny Transi...  
• Part 2 – Audio In Circuit    • Ham Radio Digital Modes: How Your Radio’s ...  
• Part 3 – Audio Out Circuit    • Ham Radio Digital Modes: Audio OUT Circuit...  
• Part 4 – (this video) COS Circuit    • Ham Radio Digital Modes:  COS Circuit Buil...  

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Works with ANY radio and YOUR imagination!
👉 Winlink
👉 Allstar
👉 APRS
👉 FT8
👉 JS8Call
👉 Packet Radio

📡 What you’ll learn in this video:
• How the COS circuit works and why it’s essential
• Step-by-step circuit build explained
• How to integrate it with your radio & computer
• Why this design makes TOADs Digital Interface unique

🔔 Don’t forget to like, subscribe, and hit the bell so you don’t miss upcoming ham radio projects and experiments!

#HamRadio #DIY #DigitalModes #AmateurRadio #RadioDIY #TOADsInterface

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