FCC Compliance on a Shoestring: A Foray into PCB Design
A number of years back, a friend of mine running a local high-school low-power FM (LPFM) radio station was transitioning from analog to digital broadcasting. He hit a massive roadblock: FCC compliance. To meet federal requirements, he needed a way to simultaneously interrupt all four of his new HD digital stations and split the signal from his Emergency Alert System (EAS) to broadcast alerts across all four channels.
Because HD radio was brand new at the time, budget-friendly commercial solutions simply didn’t exist. Having spent the previous seven years in Berlin, Germany working closely alongside electrical engineers, I decided to put that exposure to the test. I offered to help out and design and build a custom solution—a robust, reliable relay device that could plug directly into their existing equipment and solve the problem without breaking the school's budget.
Because HD radio was brand new at the time, budget-friendly commercial solutions simply didn’t exist. Having spent the previous seven years in Berlin, Germany working closely alongside electrical engineers, I decided to put that exposure to the test. I offered to help out and design and build a custom solution—a robust, reliable relay device that could plug directly into their existing equipment and solve the problem without breaking the school's budget.
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For my very first PCB layout, the final through-hole design turned out incredibly clean. Since the school was on a tight deadline, I spent a month diving headfirst into schematic capture and board layout. Fortunately, I had been working through The Art of Electronics workbook in my spare time, so I had already invested in an array of basic components and test equipment. I used Eagle CAD for the design and sent the Gerber files to Advanced Circuits in Colorado for fabrication.
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Every component was hand-soldered. Because this was a low-volume, one-off project, I opted for classic 63/37 eutectic solder rather than a lead-free alloy. The excellent flow characteristics and lower melting point gave me a good feel for through-hole soldering and ensured clean, reliable joints. Once fully populated, the board passed all bench testing with flying colors.
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I integrated classic, high-visibility through-hole LEDs for instant status monitoring. These provide a reliable, old-school visual reference for both power status and active emergency alert triggers, making it easy for the operator to verify system status at a glance.
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With the electronics finalized, I turned my attention to the enclosure. The station’s existing setup was a bit cobbled together with a lot of RCA cabling, so I wanted to design a rugged, professional housing that could stack seamlessly with their current gear. I modeled the custom enclosure in CAD, mapping out the tolerances to fit the PCB, and partnered with Protocase in Canada for the sheet metal fabrication. For a one-off prototype, their screen printing and build quality turned out exceptionally well.
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The Final Product: Rear Connectivity
A view of the back panel, showing the final input/output layout. I designed the rear interface specifically to accommodate the station's heavy use of RCA cabling, ensuring all four digital channels and the primary EAS line could be patched in securely, cleanly, and without clutter. |
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The Final Product: Front Panel
The fully assembled and finished unit, ready for installation. The custom-labeled front panel gives the device a polished, commercial-grade look. Most importantly, it successfully bridged the gap between analog and digital for a local high school, keeping them compliant, on-budget, and on the air. |