HFU HF Underground
Technical Topics => Part 15 AM and FM Station Operation => Topic started by: ThaDood on April 04, 2025, 1543 UTC
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One project that I've wanted to do for a long time, in 42 years of doing the Part 15 thang, (Since March 1983.), is to have some sort of an affordable Emergency Alert System, (EAS). Granted, Part 15'ers are not required to have an EAS, compared to their licensed counterparts. Sometime, just before the COVID-19 buddafiasco, it was brought to my attention that someone on https://www.part15.org/ blogged that someone in the FCC griped about Part 15 stations not having an EAS. Still, can't afford even a used unit, so how about building one? https://archive.org/details/yepoormanseasrev2.1/Ye%20Poor%20Man%27s%20EAS%2C%20Diagram%2C%20rev%202.1%2C%203-8-2020/ Took a while to get that together, but using an affordable Weather Radio, and a circuit using a relayed RC Time Constance, a prototype was slapped together and put in-line to my AM station in January 2020. And, it's been rocking flawlessly since. Does it look impressive? Um, no... The relayed RC Time Constance is on a pine board, the Weather Radio is wall-mounted, and I had to make an external VHF High Band Antenna, with a TV RF preamp, to make it all work. But, it does... Are there other ways to do this? Certainly, but this used an inexpensive Midland Weather Radio and parts that I had on-hand. Lately, it's been going off gangbusters with this crazy T-storms, tornadoes, and all this flooding here in West Virginia. It, hasn't failed in 5 years of test operation. (I don't think that's a bad record.) One big advantage? No software updates, like you have to do with commercial EAS units routinely. Not just Weather Alerts, but Ambre Alerts, Environmental Disaster Warnings, (And, that's happened in the WV Chemical Valley.), and the newer alert for missing seniors. Also, weekly NWS testing and even test-drills have toned-out. Operation and circuit description is described on that Archive link. One thing that Part 15'ers have a bit of freedom to do, if you can't afford it, build it. BTW, while you're there, check-out what else is on my Archive page. Found something you like, just download and use. https://archive.org/details/@thadood
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Have you seen this on youtube? I wonder if he followed your plans..
EAS Alerts on Part 15 Transmitters: A SCARY Simple Guide!
"This video demonstrates how to setup the EAS on transmitters that comply with Title 47 Part 15 of the U.S.C by adding a device that complies with Title 47 Part 11 of the U.S.C. This will allow you to send EAS to unlicensed transmitters..."
https://youtu.be/A-wQ0gT_aQY?si=FkitpWEl1UXFvz2n
I cant really understand half of what he says, but whatever it is he goes into great detail.
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Interesting.... No, I haven't seen that one. I don't hit-up Youtube as much these days, unless someone brings a neat link to my attention. However, from what I can gather, this dude is using that same model Midland Weather Radio and using the plug-in LED alert jack to trigger a change going on to something in a computer. So, my guess is that his station is using automation software, and the weather radio triggers, and interrupts, the normal scheduled programming. That's my guess. As you said, hard to understand this dude, due to his thick accent. Geez... He kind of like what I was doing when I was around 12. Nothing soldered, everything temporarily taped-up as connections, cables everywhere, etc. Hey, ya gotta' start somewhere. That's how ya learn this. BTW, he appeared to be using an FM transmitter. So, what he's got doesn't look like permissible Part 15 ops. Then again, I have no idea what country he's doing this from. One more thing, about different ways of doing a DIY EAS, Somewhere, I heard about another dude using a Kenwood car stereo, with built-in Weather Alert function, and tapping that. Sure.... Again, more than one way to do this. THANKS, for sharing!