u/ElectroMast

Look. My ears aren’t steaming yet, but the pressure is building and the fuse is lit. I am trying to set up a legal, solo, compliant FM broadcast right here in Orem, UT. I do NOT want a non-compliant, uncertified piece of junk from Amazon being shipped to a locker. I want a setup that strictly respects the FCC’s uV/m at 3 meters limit (120 uV/m at 1 meter absolute minimum before it's just static). I am trying to avoid an NAL while actually getting full-quieting operation within a tight 10-20 foot radius.

Because LPFM is completely locked down for individuals and families, Part 15 is the only legal cliff I have left to hang onto.

I need TECHNICAL HELP ONLY. No lectures on how hard Part 15 FM is compared to AM. No unsolicited advice telling me to just give up and buy an illegal import.

The Ultimatum: You have exactly until the first firework explodes over the Utah Valley on July 4th. If there are two or fewer legitimate technical comments on this thread by then, the terrestrial experiment is dead. I will pull the plug, rage-quit the airwaves, and take my audio strictly to the internet.

Don't waste my time. And DO NOT make me block you! Give me actual engineering solutions for a compliant solo FM setup. Go!

Remember that I’ll check my Reddit notifications and this thread on my profile on July 4th when the fireworks start!

Hopefully no FCC fleet of black or white direction-finding vans pull over in front of our house to file an NAL due to a complaint from a neighbor.

I am at my absolute wits' end. I have exactly 50 days left on my personal countdown clock going on 49 at 12 PM before I completely lose my mind and pull the plug on this entire operation.

I am planning to lock down a rock-solid, solo FM broadcast setup right here in Orem, Utah when the Fourth of July fireworks start. I don’t want a lecture on the FCC. I don't want a sermon on LPFM licensing. I need cold, hard, raw technical advice on optimizing the transmitter signal chain I’m going for and the antenna array I’m gonna buy soon for a localized footprint before I smash that gear with a hammer.

Worst of all the whole Orem FM dial is crowded!! NOT just the 88-108 MHz part!!!

HERE IS MY ULTIMATUM: If I do not get definitive, actionable technical comments on how to fix my signal propagation by the exact millisecond the first Fourth of July firework hits the sky over Utah Valley this year, I AM DONE.

I will rage-quit the terrestrial airwaves permanently. I’ll rip down the antenna, pack up the transmitter, and route my entire radio audio feed strictly to my internal home network like a digital hermit.

The fuse is lit. 50 days. Almost 49. Give me the technical specs on FM tuning/attenuation for a solo operator or watch me walk away and go dark forever. What do I need to know? Clock starts now.

I will check when the Fourth of July fireworks start!

Heya there everyone (pirates included)!!

I’m on a bit of a mission to get a solo, ultra-local FM broadcast back up and running here in Orem, Utah, and my Reddit deep-dives have officially begun! I was actually reading some awesome RF engineering math dropped by u/No_Coffee4280, who mentioned a theoretical minimum of ~77 dB attenuation, with a "safe" engineering margin sitting around 80–90 dB total attenuation.

If I'm reading that math right, it feels like the whole Orem FM dial is just way too crowded for standard -40 dB attenuation in the eyes of the FCC—and not just the usual 88 to 108 MHz pocket.
I want to make sure I am doing this entirely right, but my brain is hitting a bit of a wall with the engineering math required to navigate a crowded dial like ours. Could any of you RF gurus break down what kind of filtering or math I need to look at to keep things perfectly clean?
My absolute dream is to have this dialed in, tested, and ready to go just as the very first Fourth of July firework hits the summer sky. 🎆
To get there, I need some hardware help. I'm looking for a solid, extremely low-priced FM transmitter recommendation to anchor the setup. The only major catch: I strictly want to avoid the generic Chinese models (the ones known for splattering messy harmonics all over the dial and causing problems). I'd love something budget-friendly but cleanly engineered.
Any advice on the math, the Orem dial dynamics, or transmitter recommendations would make my day. Thank you all so much for being such a welcoming community!

Heya there everyone!!

I need to vent for a second because looking for a compliant FM transmitter is driving me absolutely insane. It feels like every single thing you can buy online right now—especially the cheap stuff shipped to an Amazon Locker—is an illegal, overpowered Chinese model that will immediately turn you into an accidental pirate. Unless you have an ancient phone with a headphone jack for a tiny dollar-store dongle, finding a legitimate, out-of-the-box Part 15 FM device is basically impossible.

Okay... deep breath. I'm calm now! 😅

I genuinely want to do this right. I am planning a solo, one-person FM broadcast out here in Orem, Utah, and I am entirely committed to staying within the legal limits.

Instead of using those sketchy uncertified transmitters, I’m looking at building a controlled setup: a Veronica 1-watt exciter, routed through a step attenuator, into a dummy load/antenna combo.

For the RF experts here: How many dB of attenuation am I going to need to chain together to reliably clamp a 1-watt signal down to the strict Part 15 limit (250 uV/m at 3 meters)?
Are there specific local frequencies in the Utah Valley area I should look at to ensure I don't bleed into a commercial station's guard bands?

If there are no comments by the time the first Fourth of July firework hits the sky this summer I’ll rage-quit the airwaves and stream the audio out to the internet and based off of Reddit’s Content Policy I don’t wanna do that so I really appreciate any technical guidance or sanity checks you can offer. Thanks in advance!

I am at my absolute wits' end. I’m trying to do the right thing in Orem, UT, but the market is flooded with these '7-watt' Amazon specials that are basically FCC-bait. I don't want to be a 'persona,' I don't want to be a pirate, and I CERTAINLY DO NOT want a visit from the Denver field office because a 'Part 15' device decided to blast a signal 3 miles instead of 200 feet.

I know the rules: FM is field strength (250uV/m @ 3 meters), not the 10-foot antenna/100mW rule AM gets. But every 'legal' FM dongle has the range of a wet noodle (10 feet), and every 'hobbyist' kit is a felony waiting to happen.

Does anyone actually sell a certified, high-quality FM transmitter that is physically incapable of exceeding Part 15 limits via Amazon? Or do I have to become a literal electrical engineer just to broadcast to my own backyard without looking over my shoulder for a white van? Please, no 'just stream it' or 'just do AM'—I've heard it all. I want FM to work, ESPECIALLY before Summer arrives! I want it legal, and I want to stop worrying about Rachana and Amazon lockers shipping my dad 'illegal' power levels I didn't ask for.

PLEASE HELP!1!

What equipment and procedure do I need to verify my micro-transmitter setup does not exceed 250 volts per meter at 3 meters per 47 CFR 15.239?

First: What are the legal requirements for a transmitter to be FCC Type Accepted for solo use?

Second: When does the next LPFM filing window open?