Introduction
With uprisings taking over the streets of cities and towns, effective communication for protesters and dissenters is critical. Internet tech like Signal is good for secure communication between groups, but don’t scale to tens of thousands. PAs and loudspeakers are used on site at protests to provide information and encourage unity, but can be difficult to hear clearly in crowds, even a short distance from speakers.
Free radio is a powerful tool that can supplement existing communications to provide instantaneous information and advisories across a wide area, inexpensively. Anything that might be communicated over a PA can be sent over an FM signal a greater distance with greater clarity. While the signal itself is not secure, it is also untagged – listeners cannot be identified.
For these reasons, there is a long history of protest movements using free radio. These stations were instrumental at the 1999 WTO protests and the anti-globalization protests that followed in the 2000s. Even though cell phones were available, smartphones and mobile internet were not. And, then as now, local cell networks can become saturated with traffic or tampered with by authorities.
Even recently free radio was used in car protests in the Bay Area since loudspeakers can’t reach thousands of vehicles and most cars are still equipped with pretty good FM radios.
Though the rise of mobile networks has replaced broadcast radio for many, the irony is that powerful FM transmitters have become cheaper and easier to obtain than ever before. A quick order on Ebay or Amazon can get a mobile-ready transmitter into your hands in days, whereas in 2000 you likely had to either build a kit or order a bespoke transmitter from overseas that might take weeks to arrive.
A Few Notes To Get Started
This guide is intended to help activists engaged in direct action quickly put radio to use, with basic equipment recommendations and technical advice. This is not a full primer on broadcast engineering.
We’re not providing a guide to sound production or setting up a studio. There are plenty of guides online for this, and if you’ve already got a PA then you probably already know everything you need. Since these skills have become so much more common it’s quite likely someone in your trusted circle can help.
Be advised that broadcasting on the FM dial without a license is illegal in the United States and most countries.
The advise given here is specific to the US, and regardless of where you live you should make yourself aware of the risks.
In the US you might hear about “LPFM” or low-power FM broadcasting. That’s a licensed service in the US, which requires FCC authorization, and is a whole other topic. If you’re following this guide, then you’re not setting up a real LPFM.
You may also find advice or forums on the ’net which claim you can be a “legal unlicensed LPFM” as long as you just use a few watts of power, often claiming you can do it with the equipment we list here. That’s not true, and you should know that. It is true you can broadcast without a license using a tiny FM transmitter, like the kind that plug directly into your car’s cigarette lighter. They work, but they won’t fit the bill for broadcasting to an audience outside your car.
Why should you trust this guide?
Obviously, that’s up to you. It was written by folks with decades of experience in free radio and supporting direct action with radio. We’ve become aware of many protest actions where tactical free radio could be useful, but it appears that this knowledge hasn’t necessarily been passed down to the new generation. And, while many guides to free radio have been written in that time, we noticed that most haven’t been updated for the equipment that is now widely available. Everything here is verifiable, and we encourage everyone to educate themselves.
This guide is public domain, and you are encouraged to duplicate and share widely.
Uses for an FM Transmitter
On-site Protest Communication
Used liked a PA or along side a PA, broadcast speeches, songs, chants and information to anyone with an FM radio. Encourage participants to bring portable receivers and boomboxes, or even listen on some Android phones. 5 to 15 watt transmitters can be powered easily from cars, an AC outlet or even larger lithium ion batteries.Off-site Communications
Set up a station on higher ground, possibly with higher power, to provide information to people on their way to an action, or keep friends, families and allies who can’t be there informed. Can also relay information that’s hard to monitor on-site from online sources and police scanners.Positive Messaging
Provide news, information, culture and positive vibes outside or at times in between actions, countering the dominant media messaging. Keep community members in the loop in their cars or other places where they can’t be glued to a screen.These, of course, are just a few uses. You are certain to find more of your own.
Buy a Transmitter
For at least the last five years inexpensive and reasonably well-built transmitters have been imported from China and are easily available on eBay and Amazon. That’s what we’ll recommend here because they are so easy to get and operate.That said, they do vary widely in quality control, though it appears that most come from the same one, or maybe two factories, sold under an array of brand names. A radio engineer might scoff at them, and we’d agree that they’re not suitable for a licensed station or 24/7 broadcasting (but we don’t recommend that anyway). Still, they are quite reliable and good-sounding enough for tactical, pop-up broadcasting.
Be aware that regardless of what the listing says, these transmitters are not actually authorized to be used on the air in the US, whether you have a license to broadcast or not (even if you can buy one on Amazon). Often they’ll be advertised for use at churches or outdoor venues, which is not permitted under the law. Even the cute tiny ones with just a 1/10 watt are not permitted. However, it’s not illegal to buy or own one of these transmitters, and as we note below, using them really is not much of a risk these days if you take precautions. Nevertheless, this is something you should know going in.
Because these transmitters are not strictly authorized, there’s a chance they could become less available or disappear entirely from the US market. This hasn’t seemed to be a priority for the FCC, but you never know when the sleeping giant will awaken.
For On-Site Action and Mobile Broadcasting: 15 Watt Transmitter
Model numbers and/or brands: ST–15B, Niorfnio, HLLY CZH–15, Signstek ST–05B, Retekess
Cost: $50 - $150 +shipping
Size: 4“ w, 2.5” h, 5.5" deep
Power requirements: 12volts DC, 3 amps, positive-tip EIAJ–04 barrel plug
Range: .5 - 3 miles, depending on height of antenna
Purchase from Ebay:
If you search “15w transmitter” (for some reason “15w” works better than “15 watt”) on you’ll see at least a couple dozen listings for pretty much the same transmitter at a variety of different pricing. They’re small and light, but in a sturdy aluminum case.
As of June 2020 it seems like all the sellers are in China, which adds some additional cost and time for shipping. However, these days delivery time can be as little as a week to the west coast.
Purchase from Amazon:
On Amazon a similar search of “15 watt fm transmitter” turns up several models, all pretty much identical to each other and the ones on Ebay. You’ll pay more on Amazon (and help line Jeff Bezos’ pockets), but you may also get it quicker, from a US warehouse (or even Prime!?). Just be sure it says 15 watts – there are a number of identical looking transmitter that only put out 1/2 (.5) watts. They’re less useful.
What to Look for
Look for a package that comes with a 1/4 wave stick antenna and magnetic mount. The antenna can attach directly to the transmitter, but you’ll get better performance with the magnetic mount which is perfect for putting on the roof of a vehicle or any magnetic metal surface, which can help you get it above a crowd easily (bodies block radio waves).
Some might be packaged with what is called a “1/4 wave ground plane antenna.” These are more efficient, but require a proper antenna mast and cable, and so are more appropriate for a fixed location, and not great for mobile or use at an action.
Other Info
They all have a 1/8“ microphone input, which is adequate in a pinch, but it’s better to use the 1/8” stereo line input, which can come out of your mixer or PA. Some have a Bluetooth input, but these tend to be noisy and buggy.
The power supply is a brick similar to what you’d use with a small laptop, with a standard barrel plug power input on the transmitter itself. In a vehicle you should be able to power it from the cigarette lighter using a simple adapter that has a center-positive barrel plug on it, such as this.
15 watts is a good starting point because it’s a relatively safe amount of power – you’re not going to get burned if you accidentally touch the antenna while broadcasting – but it’s enough to cover many city blocks.
For Off-Site and Fixed Location Broadcasting: 30+ Watt Transmitter
There’s a lot more variety in models and brands in this class of transmitter, which makes it seem like a lot of these were actually designed for quasi-broadcast operations rather than the hobbyist uses the 15 watt transmitters are made for. As a result this advice is a little less precise.
Also, you won’t find these on Amazon. Ebay (or other China-direct sources) are your best bet.
Note that you can certainly use the 15 watt transmitters listed above at a more fixed location. However, the supplied antenna is going to be a limitation, especially since you want to get your antenna outdoors and as high as you can. That’s where a 1/4 wave ground-plane antenna is a better bet.
30 Watt Transmitter
Model numbers and/or brands: HLLY TX–30S
Cost: $200 - $350 +shipping
Size: Size: 19“w x 4”h x 12" deep
Power requirements: 12.8volts, 7 amps, positive-tip EIAJ–04 barrel plug
Range: 2 - 5 miles, depending on height of antenna
A big step up in power doesn’t necessarily double your broadcast distance, but it helps a lot. You also get more reliable RCA connectors for audio, instead of just a 1/8" jack. There won’t be a direct microphone input, so you’ll want to use a mixer with a mic input.
You might be best off looking for a package that includes a 1/4-wave ground-plane antenna, just to keep things simple, though you can buy one separately. With this, you’ll also need to mount the antenna to a mast of some kind, outdoors, as high as you can, but away from any power lines. More advice below.
50 Watt Transmitter
Model numbers and/or brands: Warner RF FMT5.0, NIO-T50M,
Cost: $500 - $700 +shipping
Size: Size: 19"w rack mount
Power requirements: 120/240VAC
Range: 3 - 10 miles, depending on height of antenna
These definitely look more like pro broadcast transmitters, and the two models listed above are definitely from different manufacturers. Like the above, they’re only on Ebay and only delivered direct from China.
With 50 watts you’re playing with more serious power, and again you might want to look for one packaged with an antenna. Search “50w fm antenna” to find those specifically.
The size of a rack component and running of AC power they’re less suited to portable use. Though you could certainly fit one in a flight case if that’s your thing. If you don’t know what that is, then it’s not your thing.
More than 50 Watts: Not Recommended
We really don’t recommend going above 50 watts unless you know what you’re doing. You need to take more care with citing your antenna and it’s easier to accidentally fry your transmitter. Plus, you also increase the possibility of messing with your neighbors' radios, TVs and other RF appliances, which isn’t nice, and also increases the chance of complaints.
This guide isn’t prepared to give you that extra knowledge to handle higher powers, and if you do know what you’re doing, then you don’t need us to help you.
Alternate Source: Free Radio Berkeley
Folks in the Bay Area may have the opportunity to build their own transmitter with Free Radio Berkeley, which has been supporting free radio for several decades. However, their website is only sporadically updated, and all indications are that you have to go to their physical location in Berkeley, CA. Your best bet is to contact them directly.
Find a Frequency
If you want your broadcast to be heard, then you need to find an open frequency. While it may sound exciting to interfere with your local conservative racist blowhards, you’ll be a flea going up against a flamethrower, and your signal won’t go far enough to be useful.If you don’t mind being on the left end of the dial 87.9 FM is a good place to start – but still follow the steps below. By and large the FCC does not license stations for this frequency, but most radios can still receive it.
Step One: Tune the Dial
One simply way to start the process is to tune a good car radio around the dial nearby where you want to broadcast from. Look for a frequency that is mostly static, that’s at least .4 mHz from another station. That is, if you find clear station (mostly static) at 95.5 FM, make sure there isn’t another strong signal at 95.3 or 95.7. Stations at 95.1 or 95.9 are OK. This way your signal won’t get much interference, and you won’t interfere with other stations (increasing your hassle). Try this both during the day and at night.
If you don’t have access to a car, try to find a very high quality portable radio with a digital tuner.
Step Two: Verify Your Results
If you think you’ve found an open frequency, verify it online. Radio Locator is a very cool tool that lists out all the stations that are potentially receivable in a given city, zip code or location. Keep in mind that it locates every station, even if it really isn’t easy to receive.
Luckily Radio Locator helps you figure that out with a little Vu meter graphic. If you see a station listed with the needle to the left 
and you can’t hear it at all, then you’re probably safe.
Note that their database is working from stations that should be on air, and that there’s a chance that the frequency that you’d like to use is claimed by a station that is not broadcasting right now. So if you see a station listed that you just can’t receive, look into its situation. Especially check out local radio message boards. If you can’t find the station elsewhere online or someone says they’re off-air, then you’re probably good-to-go.
Also, Radio Locator will help you find unused frequencies. The same caveat applies, so in most major cities the tool will probably tell you “no vacant channels on the FM dial,” which may be technically true. However, it will probably still recommend a few other frequencies as best or next best. Definitely check those out.
Finally, it’s good to get into the habit of tuning in to your frequency before turning on your transmitter, just to be sure. There’s a chance that another free radio station might be there, too, and you may not want to interfere (but that’s up to you).
If you’re in an area where your dial is so crowded that there is no truly clear frequency, then may we suggest that you try not to occupy the frequency of a college, community or even public radio station, even if it’s distant.
Broadcast!
This part’s simple, just do these things in order:
- Tune your antenna – shorten or lengthen it for your desired frequency according to the instructions provided
- Site your antenna where you want it to be
- Plug your antenna into your transmitter
- Plug your audio source into your transmitter
- Plug the power source into your transmitter
- Turn it on and select your frequency
- Broadcast!
Note that antennas work best outdoors, mounted as high as possible, away from obstructions like buildings, trees and (especially) power lines. Remember, antennas conduct electricity well, so really do stay away from power lines and don't broadcast during electrical storms unless you've properly grounded your antenna. And try not to touch your antenna while broadcasting – especially for transmitters with more than 15 watts
There's no perfection here. It's more important to broadcast than to have the perfect broadcast. So do your best to find a good location and go.
The Ethic of Free Radio For All
Radio stations don’t need to broadcast 24/7. Too many stations–commercial and non-commercial–just fill time with automated jukeboxes, with no humans involved. Instead more voices can be heard when we share the airwaves.
We want to hear dozens or hundreds of stations take to the air in the cracks in the sidewalk, the frequencies where the voices of the many can be squeezed in between the voices of the few. That’s why we encourage you to use a frequency when it’s needed, and then go off-air when you don’t so that another station can. Share this knowledge and share the resource.
As a practical matter, broadcasting without a license is more sustainable when it’s intermittent. The FCC has few resources to hunt down unlicensed operators, and playing cat and mouse is surprisingly effective (more on that below).
Precautions
Yes, yes, broadcasting without a license on the FM dial is technically against the law. However, so is speeding 5 MPH over the limit, or jaywalking, yet people do those things all the time. Sure, once in a while someone gets caught. But most of the time, not. Free radio is just like that.
Just like speeding, a little bit of caution and forethought goes a long way. The FCC aren’t cops and they’re not patrolling the airwaves looking for pirates. Instead, they act on complaints, and are very slow to respond. Make yourself hard to identify and find and you’ll have a very good chance you’ll never be caught.
First thing, don’t broadcast 24/7. It’s not just a nice way to give others a chance to broadcast, it also means it’s less like the FCC will find your station. It’s simple: if you’re not broadcasting when the FCC goes looking, then you can’t be found.
Budget cuts mean the FCC has fewer enforcement personnel, especially outside the biggest metro areas, which means that they might need to travel from hours away to snoop out a suspected pirate. Plus even local FCC staff don’t want to work outside business hours if they don’t have to, so broadcasting after 5 PM and on weekends makes you more of a pain to track down. Also, the more unpredictable your broadcasts are, the harder they are to track down, too.
Change locations or go mobile. Broadcasting from different locations means more work for anyone who wants to find you. All of these transmitters we mentioned above run on 12V DC which and so they can be easily adapted to run from your car’s 12V outlet. Or you can get a 12v mobile battery like the ones made to jump car batteries if you don’t want to be tied to a car.
Be thoughtful with publicity. When supporting direct action you’ll likely want to let participants know the frequency in advance, and know to bring radios. That’s fine, as long as you keep in mind that the cops will likely find out and tune in, too. With a few notable exceptions, local cops don’t enforce broadcast laws.
That said, more wide publicity increases the chances of complaints to the FCC, and that’s what’s most likely to lead to action from them. Therefore we suggest using the tactics of security culture. Use pseudonyms and stay anonymous on-air. If you’re broadcasting from a fixed location on a semi-regular basis keep that location a secret. It doesn’t make sense to try to operate an open-studio community-style radio station without a license (that’s what LPFM is for).
Also, don’t talk to the press. It may seem like a great idea to have the local alternative weekly spread the word, even if they promise anonymity. But don’t think for a second that article won’t land right on the desk of the local FCC office director making your station public enemy #1. Good publicity for you is bad publicity for the FCC, and will give them every incentive to step up efforts to find you and shut you down.
Use secure communications. You don’t need a website, but if you feel the need to set one up don’t use a Blogspot site associated with your Google or Gmail account. And sure as shit don’t use Facebook. That’s because it’s so hard to figure out what digital fingerprints you’ve left behind with these services. We use Neocities because it’s pretty clean and run by cool people. Same precautions go for email and other social media. For email we use ProtonMail because it was set up by Swiss scientists to be secure. Of course, we don’t trust our government, so we also access it using “incognito” mode in our browser over a VPN. For free/inexpensive solutions consider the Tor browser. Don’t put your station’s email on your primary smartphone, and while you’re at it, consider getting a burner phone to use for anything broadcast related, while keeping your primary phone turned off (or at least with GPS off and in airline mode) while broadcasting.
Don’t worry. Follow this advice and it’s unlikely you’ll come face to face with an employee of the FCC. Remember, they’re not cops. If someone comes to your door saying they’re from the FCC, don’t talk to them. Don’t let them in. Don’t answer their questions. They can’t arrest you. In the the most extreme cases they can get a warrant and show up with cops, but that only happens after they’ve made quite a few unsuccessful visits. When was the last time you heard about an “FCC raid” in your town? Right.
So in the unlikely event the FCC shows up to your broadcast location, and you’ve successfully kept your mouth shut and not let them in, after they go away shut down the transmitter and relocate your station. Maybe consider changing the name and frequency the next time you broadcast so that it seems like a whole new station. Keep the FCC playing Whack-a-Mole, because nobody ever wins that stupid game.
Extra warning for New York, New Jersey and Florida:
In all but three states local police do not enforce laws on unlicensed broadcasting. However, New York, New Jersey and Florida all have state laws on the books. They’re rarely enforced in New York and New Jersey, and somewhat more frequently enforced in Florida. We note this not to scare you off, but to keep this in mind. In these states we recommend making friends with local radio activists (often found in community radio) who might be able to give you the lowdown for your area.
You might also be interested in some advice for internet broadcasting in the spirit of free radio.