FM Transmitters For Churches – What FM Transmitters Are Legal For License-Free Use?

Drive-in church services performed with the help of FM transmitters existed long before the outbreak of COVID-19, but the pandemic made these services much more popular than before. Consequently, the number of FM transmitter sales increased significantly over the past two years. 

The problem with the FM transmitter market in the US is that most of the transmitters sold on eBay and Amazon in the past two years are not legal for use in the US. 

You see, the US has very strict federal laws regarding AM and FM transmissions. These laws limit the licensed and unlicensed use of FM transmitters, and you have to obey these laws to stay out of trouble. The fines for unlicensed use of long-range FM transmitters can be astronomical. You can even end up in jail

This article’s goal is to list and analyze all the laws and requirements you must comply with when using FM transmitters in the US. I will also explain what’s considered legal (and illegal) FM transmission, and offer you some legal suggestions that don’t require licensing. 

I’m aware that the title says FM transmitters for churches, but all the FM transmitters I am about to recommend are suitable and legal for personal use, parking lots, drive-in theaters, schools, shopping malls, etc.  

FM Transmitters For Churches

Here’s a short breakdown of my selection of FM transmitters for churches:

FM TransmitterInputsFCC Part 15 ComplianceRange
BV AXS-FMTD3.5mm x1 - Digital COAX x1 - Optical TOSLINK x1YesUp to 300ft
Progressive Concepts ACC100RCA x1Yes50-300ft
BaseWish CZE-05B3.5mm AUX x1 - MIC x1YesUp to 980ft
CCrane Digital FM Transmitter 33.5mm x1YesUp to 50ft
Whole House FM Transmitter 3.03.5mm AUX x1 - 2.5mm MIC x1YesUp to 150ft
Topics Covered

Best FM Transmitters for Churches – AudioGrounds’ Favorites

FM transmission is a delicate and highly regulated matter in the US. Using equipment that is not compliant with the FCC Part 15 regulations to transmit on FM bands can get you in serious trouble. 

So, I would advise you to stick to well-known reputable brands, preferably American brands. They know the laws and make their equipment in accordance with those laws. You can’t expect the same kind of professionalism from no-name Chinese brands. 

My top recommendations are BroadcastVision AXS-FMTD and Progressive Concepts ACC100. These FM transmitters are made by US-based manufacturers and are FCC Part 15 compliant. 

The only problem with the US-made FM transmitters is their price. They are significantly pricier than generic Chinese FM transmitters you can find on Amazon or eBay. 

The best Chinese FM transmitter compliant with FCC Part 15 is BaseWish CZE-05B. If you’re looking for a cheap alternative to those expensive US-made transmitters, BaseWish CZE-05B is the way to go. 

FM Transmission in the US – Legal Restrictions

When it comes to FM transmitters, especially transmitters for license-free use, knowing and understanding the legal regulations is the most important thing. Ignoring the law can get you in trouble, so make sure to read the following chapters. 

Title 47 Part 15

FCC’s Title 47 Part 15 is the most important literature you need to read before even thinking about buying an FM transmitter. All the prerequisites you must meet to transmit on FM and AM frequencies are listed in this document. For a simplified version that only deals with low-power non-licensed transmissions, check out this document.

I will now list the most important legal limitations from Title 47, Part 15. Since licensed FM transmission requires lots of paperwork. time, and money, I will concentrate on license-free FM transmissions. 

Non-licensed use of FM transmitters is regulated through sections 15.109, 15.209, 15.231, and 15.239. The most important section is 15.239.

This section defines that the intentional non-licensed broadcast on the FM band must be kept within the 200 kHz band, centered on the operating frequency. The whole 200 kHz band should be within the FM band (88 MHz – 108 MHz). So, your operating frequency cannot be 88 or 108 MHz. You can choose frequencies between 88.1 and 107.9 MHz. These are legal frequencies.

The second rule you must comply with is related to the FM transmitter’s field strength. The maximum allowed field strength of an FM transmitter measured at a 3m distance must not exceed 250µV (microvolts) per meter. 

Title 47, Part 15, Section 239

Title 47, Part 15, Section 239

Some sources suggest that non-licensed FM transmission is limited by the FM transmitter’s power. More specifically, you may hear people saying that the max allowed power is 100mW or 0.1W. This is not valid information.

Once again, Part 15 limits the field strength and not the power output. The field strength is partially affected by the power output of the transmitter, but it’s also affected by the antenna efficiency. 

The antenna length is not defined by Part 15. As long as your FM transmission field strength stays below 250 microvolts per meter, the antenna length doesn’t matter. 

In practice, Part 15 limitations mean that, without applying for a license, you can only use extremely low-power FM transmitters with a range of up to 200ft (or 61 meters). This is the only legal way to perform license-free FM transmissions. 

In addition to section 15.239, a few more sections limit the license-free FM transmission. More specifically, section 15.209 limits the field strength of the radiated transmissions outside your 200 kHz band where the operating frequency is located. The limit for radiated transmissions is 150 µV/m (measured at 3m)

In other words, your FM transmitter must be able to lock the transmission onto the selected operating frequency and prevent out-of-band transmissions. 

Section 15.231 also limits the field strength of periodic transmissions and intermittent control signals to 500 and 1,250 µV/m, measured at 3 meters.

 License-Free FM Transmission – Field Strength Limitations Defined by the CFR Title 47, Part 15

FM Transmission 88-108MHzMax. Field StrengthSection
Intermittent Control Signals1,250 µV/m (@3m)15.231
Periodic Transmissions500 µV/m (@3m)15.231
Any Transmission (within 200kHz band)250 µV/m (@3m)15.239
Any Transmission (outside 200kHz band)150 µV/m (@3m)15.209

Besides these limitations regarding the field strength of FM transmission, FCC also requires that you use FCC-approved FM transmitters. These transmitters must have a valid FCC ID. If they don’t have a valid FCC ID indicating they are compliant with Part 15, the use of such transmitters is technically considered illegal, even if you stay within the defined FM transmission limits. 

I will explain how to check whether an FM transmitter is approved by the FCC or not in one of the following sections. 

Licensed FM Transmissions – Commercial, Non-Commercial, and Low-Power FM Transmissions

If you want to achieve a range greater than 200ft, your only legal option is to apply for FM or Low-Power FM transmission license

The whole process of applying is quite time-consuming. It also requires lots of paperwork and lots of money, even if you want to get a relatively short range of just 3-5 miles. 

Applying for an LPFM (Low-Power FM) license is certainly easier than applying for a commercial long-range FM license, but it’s still not easy. Not at all. 

Below, I have listed CFR titles and sections regulating licensed FM transmission.

Type of FM TransmissionRegulations
Commercial FM BroadcastTitle 47, Part 73, sections 73.201-73.333

Title 47, Part 73, sections 73.1001-73.5009
Non-Commercial Educational FM BroadcastTitle 47, Part 73, sections 73.501-73.599

Title 47, Part 73, sections 73.1001-73.4280
Non-Commercial Low-Power FM TransmissionTitle 47, Part 73, sections 73.801–73.881

Title 47, Part 73, sections 73.1001-73.4280


In January 2020, the US Congress enacted the so-called PIRATE Act, which is supposed to improve enforcement capabilities regarding the prevention of illegal broadcasting on FM and AM frequencies. 

This law allows the FCC to enforce much higher penalties than before. The fines go from $100,000 per day to $2M in total.

The PIRATE Act also grants the FCC the authority to take enforcement actions against landlords and property owners if they knowingly and willfully allow pirate radio broadcasts on their properties.

FCC Statement Regarding Illegal Radio Stations

Pirate Radio: Unlicensed & Illegal Broadcasting

In March 2023, the FCC proposed the first PIRATE ACT fines against pirate radio broadcasters. The FCC proposed the highest possible penalty ($2,316,034) against a couple from Queens, NY who illegally operated a pirate radio called “Radio Impacto 2” for years.

$2M Fine for a NY-Based Pirate Radio

$2 Million Fines For New York City Radio Pirates

I’m not mentioning these fines because I want to scare you. I’m just trying to emphasize how serious transmitting illegally on AM or FM radio frequencies can be. Your transmission can interfere not just with legal radio stations but with many other services using radio waves (ambulance, fire department, and police communications, as well as airplane communications). THIS IS A SERIOUS THING. DO NOT BROADCAST ILLEGALLY.

The PIRATE Act doesn’t include unlicensed transmissions compliant with Part 15. People using Part 15 compliant (and certified) equipment for short-range transmissions will not be subject to the PIRATE Act. In other words, this kind of transmission is considered legal. 

How to Use an FM Transmitter?

Once you find the right kind of FM transmitter (the one compliant with the Part 15 regulations), using it should not be a huge hassle. 

Before turning on your FM transmitter, you need to examine and analyze the FM band in your area. You need to find empty frequencies and stay away from existing licensed transmissions.

Ideally, you will find an empty 200kHz gap and select the central frequency within that gap. If you manage to find a bigger gap, that’s great – select the frequency in the middle of that gap. That way you will minimize interference. 

Once you analyze the FM band in your area, you can connect all the equipment you want to use to your FM transmitter (phones, microphones, soundboards, etc.). 

Depending on the connections available on the transmitter, you may have to figure out some workarounds. If the outputs on your equipment don’t match the inputs on the transmitter, you will have to buy some additional audio cables and interconnects – you just need to find the right cable types for your setup.

After you set everything up, you can turn on your transmitter. Some FM transmitters will start to transmit the moment you plug them in. Others will have a power switch. When you turn it on, you need to tune it to an empty frequency – that’s why you had to analyze the FM band. 

If the FM transmitter has an adjustable RF power output, start with the lowest output and measure your range using a portable FM radio or the FM radio in your car. Increase the RF power output until you reach 200ft (that’s the legal limit). If the range is longer than 200ft, lower the output. 

When you set everything up, you can start transmitting legally using your Part 15 FM transmitter. 

Before we start with my FM transmitter suggestions, here’s a quick recap:

For unlicensed FM operations, you need an FM transmitter compliant with the FCC Part 15 regulations.

The transmitter should have a valid FCC ID

The max allowed field strength on the operating frequency is 250 µV/m (measured at 3m), while the max allowed field strength outside the 200kHz band where your operating frequency is located is 150 µV/m. The max allowed antenna length is not specified as long as you stay within the field strength limits. 

The max allowed RF power output of the FM transmitter is not specified by the FCC. However, in practice, the max allowed RF power output is approx. 0.1W

In practice, the max allowed range for license-free transmission is approx. 200ft (61m). This is not strictly specified by the FCC. The FCC only specifies the max allowed field strength. 

Causing interference to licensed radio stations, ambulance, fire department, and police communications, as well as airplane communications is considered illegal. Part 15 FM transmitters used for license-free operations should accept any interference coming from other legal and licensed FM transmissions. 

You are not allowed to transmit on frequencies 88MHz and 108MHz. The whole 200kHz band where your operating frequency is centered must be kept within the FM band. Your operating frequency can be any frequency between 88.1 and 107.9MHz. 

All Chinese FM Transmitters Reviewed

All Chinese FM Transmitters Reviewed

Best FM Transmitters for Churches

Best Overall – BroadcastVision AXS-FMTD


What I Liked About BroadcastVision AXS-FMTD

As you have seen, the legal regulations regarding the use of FM transmitters are very restrictive and are different for every country. So, it’s only natural to buy such equipment from a US-based manufacturer who knows all the federal laws and makes equipment in compliance with those laws. The FCC grant for the AXS-FMTD proves Part 15 compliance (see the image below).

AXS-FMTD – FCC Part 15 Compliance Grant

AXS-FMTD – FCC Part 15 Compliance Grant

The unit operates on frequencies between 88.1 and 107.9MHz, as required by the FCC. Unlike most other FM transmitters, this one has both analog and digital inputs. It features one 3.5mm AUX jack, one digital COAX input, and one optical input, which allows you to connect all kinds of equipment.

AXS-FMTD  inputs (image source – AXS-FMTD user manual)

AXS-FMTD  inputs (image source – AXS-FMTD user manual)

The transmitter easily locks onto the selected frequency and delivers stable FM transmission with a pretty impressive range. The sound quality is great and without any noise, even at 200ft. 

BV AXS-FMTD FM Transmitter – Introduction and How to Set Up and Use It

BVE AXS FMTD Digital / Analog FM Transmitter

Where BroadcastVision AXS-FMTD Should Improve

I didn’t have any problem with the power adapter, but I’ve read that other reviewers had issues with their power supplies. It’s only fair to warn you that the power supply may introduce noticeable noise on the operating frequency, even when you’re not transmitting any audio.

The unit doesn’t allow you to adjust RF power output, which seemed necessary in certain situations. This unit is FCC-approved, but I have noticed that the range of the unit can easily exceed 500ft, which is much more than the allowed 200ft. Some reviewers have even measured 1,000+ feet. 

Having this range in mind and the inability to adjust the power output, I would recommend being careful when using this FM transmitter. Always use empty frequency and, if possible, position the transmitter in a way that the FM signal doesn’t go outside your property.  


BroadcastVision AXS-FMTD is a great-performing little FM transmitter. It’s easy to use, offers versatile connectivity, and delivers a stable FM signal with amazing sound quality. 

This transmitter’s range can exceed the max allowed 200ft. It can actually be much greater than that, which technically makes certain applications illegal, even though the device is FCC-approved.

Best FM Transmitter Under $300 – Progressive Concepts ACC100

  • FCC ID: MBM-ACC100

What I Liked About Progressive Concepts ACC100

Like the previous FM transmitter, ACC100 is made in the US and compliant with Part 15 regulations. Progressive Concepts have four versions of this transmitter: Analog Mono FM Transmitter (ACC100), Analog Stereo FM transmitter (ACC100S), Digital Mono FM Transmitter (ACC100D), and Digital Stereo FM Transmitter (ACC100DS).

Regardless of the version you order, the package includes a fixed wire antenna and a 12V/100mA power supply. Analog versions will come with an RCA cable, while the versions with digital inputs don’t come with audio cables.

The analog mono version has a single RCA input, while the stereo version has dual RCA inputs. Digital versions feature only digital audio inputs – digital coax and TOSLINK.

Every transmitter version is packed inside a sturdy metal chassis.

Progressive Concepts ACC100 – FCC Part 15 Compliance Grant

Progressive Concepts ACC100 – FCC Part 15 Compliance Grant

ACC100 delivers a very stable transmission. Thanks to its PLL microcontroller, the transmitter can lock on to the selected frequency and reduce the emissions outside the operating frequency.

The noise during transmission is barely noticeable at a 200ft distance thanks to the built-in RF circuit and control circuit board. 

Depending on the conditions, this transmitter’s range can reach 300ft. On average, the range is around 200ft.

Where Progressive Concepts ACC100 Should Improve

Instead of four different versions with different inputs and output modes (mono and stereo), I would like to see one stereo unit featuring all the analog and digital inputs. 

I understand the price of the unit would have to be higher (probably more than $500), but it would make the transmitter more versatile and easier to use. I wouldn’t have to buy interconnects and figure out ways to connect different types of equipment to the transmitter.


I really liked this one. It is super-easy to use, delivers stable FM transmissions, and the sound quality is great. There’s practically no noise. Unlike the previous AXS-FMTD, ACC100 stays within the FCC limits for license-free FM transmissions most of the time. 

The only issue is poor versatility.

Best FM Transmitter Under $100 – BaseWish CZE-05B

  • FCC ID: 2ASVO-05B7CT200

I have already said that buying US-made equipment is a smarter solution because US-based manufacturers know the US laws and make equipment compliant with those laws. Also, I have said that most of the equipment sold on Amazon is actually illegal for use in the US. But not all. 

What I Liked About BaseWish CZE-05B

The biggest problem with US-made FM transmitters is their price – they are simply much more expensive than Chinese FM transmitters sold on Amazon. One particular FM transmitter from Amazon I’d like to recommend is the Basewish CZE-05B. Unlike many other transmitters made in China, this one is approved by the FCC and compliant with Part 15 regulations (see the image below). 

BaseWish CZE-05B – FCC Part 15 Compliance Grant

BaseWish CZE-05B – FCC Part 15 Compliance Grant

The unit comes with a detachable RF antenna, power brick, and a male-to-male 3.5mm audio cable. The chassis is made of aluminum alloy. 

On the front, there’s a large monochromatic display, two inputs (mic and 3.5mm) with volume controls, a power button, and UP/DOWN buttons for selecting the frequency and output mode. The controls are very intuitive, responsive, and easy to use.

CZE-05B features two power output modes – LOW (0.1W) and HIGH (0.5W). The HIGH mode gives you a better range, but I don’t think this kind of range is legal for license-free use. The advertised max range is 980ft. I would suggest changing the output mode to LOW before you start transmitting.

The range is good, even at the LOW setting. It may exceed 200ft occasionally, but it stays within the FCC limits most of the time. The transmission is stable and the sound quality is satisfying. 

BaseWish CZE-05B – Setup Instructions

CZE-05 FM STEREO TRANSMITTER - operation manual

Where BaseWish CZE-05B Should Improve

You may experience static noise occasionally. If that happens, try restarting the transmitter, relocating it, or selecting a different (empty) FM frequency. Some users have had issues with the power brick – they claimed the power brick was causing the noise. If this happens to you, try some alternative type of power supply. 


If you’re looking for a legal, Part 15-compliant FM transmitter for church services, this is your best option. The unit has its flaws, but it still offers great performance for the price. Just don’t forget to set the RF power output to LOW before using it. The range in HIGH mode exceeds the limits allowed by the FCC for license-free use.

Best Battery-Operated FM Transmitter – Digital FM Transmitter 3

  • FCC ID: YXEFT007

What I Liked About the CCrane Digital FM Transmitter 3

CCrane is another US-based company, famous for its radios, AM/FM/Wi-Fi antennas, Wi-Fi solutions, transmitters, and all kinds of audio gear. Their FM transmitters and other equipment are made in China, but they are still compliant with the FCC regulations.

CCrane’s portable, battery-operated FM transmitter named simply Digital FM transmitter 3 is one of my favorite portable solutions. It’s tiny, easy to use, and doesn’t require a complicated setup. This transmitter may not be as powerful as the previous three, but it’s still a good choice if you want to cover smaller areas (up to 50ft range). 

As always, the most important part is here – the unit is certified by the FCC and compliant with Part 15 regulations (see the image below). 

CCrane FM Transmitter – FCC Part 15 Compliance Grant

CCrane FM Transmitter – FCC Part 15 Compliance Grant

The transmitter can fit the palm of your hand. On the front, you have a tiny screen, a power button, and two tuning buttons. On the left side, there’s a single 3.5mm stereo input and a DC input. On the right, there’s an old-school volume dial. On the back, you will see a sticker with all the basic information and a battery compartment.

The unit runs on two AA batteries. If you don’t have the batteries or don’t want to use them, you can always plug in the supplied power adapter and use it like that. 

You can easily tune to an empty frequency and start transmitting. The transmitter locks on to the frequency you selected and doesn’t shift to adjacent frequencies, which guarantees stable transmission. The sound quality is satisfying if you stay within the advertised range (50ft). 

It’s also worth mentioning that the CCrane transmitter is fairly cheap (costs around $70).

CCrane FM Transmitter 3 – Setup and Operation Instructions

How to use the C. Crane FM Transmitter 2 for church services, parking lot concerts, or other events

Where CCrane Digital FM Transmitter 3 Should Improve

CCrane wanted to stay within the legal range limits and made it significantly shorter compared to other Part 15 FM transmitters. Extending the range to 150-200ft would make this transmitter even better. 


For the price, you can’t get a better portable Part 15 FM transmitter. The range is shorter compared to other Part 15 FM transmitters, but it’s still satisfying for the price. 

Most Feature-Rich Portable FM Transmitter – Whole House FM Transmitter 3.0


What I Liked About Whole House FM Transmitter 3.0

Like the CCrane transmitter, this is a portable FM transmitter. It has more features and delivers slightly better performance than the CCrane transmitter, but it also costs more.

It comes in a rich package with all kinds of equipment and audio cables.

You will get a charging adapter, micro USB charging cable, 3.5mm (M) to 3.5mm (M) audio cable, 3.5mm (M) to RCA (F) audio cable, and RCA (M) to 3.5mm (F) audio cable. You will also get a car adapter and two RF antennas – a detachable and adjustable SMA antenna (legal in the US), as well as a wire international antenna (not meant for use in the US).

The unit has a simple and intuitive button layout. On the front, there’s a display showing the frequency, MIC/LINE levels, battery status, and other info. Below, you have five buttons – 3 preset buttons, a CYCLE button, and a MUTE button. The CYCLE button is used to shift between various adjustable features (frequency, US/EU mode, power mode, MIC, and LINE levels). 

On the right side, you have + and – buttons. Once you select the feature you want to adjust using the CYCLE button, you will use these buttons to go up or down. On the left, there’s a micro USB port. 

On the top, you have two inputs – a 3.5mm LINE-LEVEL stereo input and a 2.5mm mic input (the mic is not included). The unit allows you to operate MIC and LINE-level inputs at the same time. The antenna connector and the power button are also located on the top.

On the back, you will see a battery compartment. The unit runs on three AA batteries, but you can also use the included adapter and power cable. On the back, you will also see the FCC ID proving that the unit is Part 15 compliant.

Whole House FM Transmitter 3.0 – FCC Part 15 Compliance Grant

Whole House FM Transmitter 3.0 – FCC Part 15 Compliance Grant

Whole House Transmitter 3.0 delivers decent performance between 50 and 100ft. You can hear the sound even at 150ft, but there’s lots of noise. 

The unit can operate in two modes – LOW POWER and HIGH POWER, but you won’t find any info about these two modes in the manual. When you switch from LOW (which is the default mode) to HIGH, you will get a much better signal and sound quality at 150ft, but I’m not sure if this is legal in the US. 

If you want to try the HIGH POWER mode, you can press the CYCLE and MUTE buttons simultaneously for a few seconds. You will see a tiny lightning symbol right above the operating frequency. 

Note that you’re doing this at your own risk! I can’t guarantee that operating in HIGH POWER mode is legal in the US.

Whole House FM Transmitter 3.0 – Review

Whole House 3.0 Part 15 FM Transmitter Review

Where Whole House FM Transmitter 3.0 Should Improve

The audio cables as well as the charger and charging cable that come with the transmitter are of poor quality. I would strongly recommend using higher-quality cables and adapters. The adapter that comes with the cable can also cause lots of noise during transmission.


This transmitter is a mixture of good and bad things. The range is adequate and the unit is FCC-certified. If you decide to use a higher-quality adapter and audio cables, you can even get a decent performance with minimal noise. However, the original equipment that comes with the transmitter is pretty bad. 

How to Check Whether an FM Transmitter Is Compliant with Part 15 Regulations?

You may think that everything you buy legally on Amazon or eBay is legal for use in the US, but sadly, that’s not the case. At one point during the pandemic, the Amazon was flooded with Chinese FM transmitters for churches, parking lots, and drive-in theaters. 

Most of these transmitters sold on Amazon were not approved by the FCC. Some sellers even faked the FCC ID to prove their transmitters’ legality. Luckily, you can easily check whether the transmitter is compliant with Part 15 or not. 

Option 1 – Check the Specs (Easy but Not So Reliable Option)

As discussed earlier, for legal FM transmission you need a transmitter with a max field strength of 250 µV/m, measured at 3m. Also, the field strength outside the 200 kHz band you’re locked onto, should be lower than 150 µV/m. If you can find the info about the field strength in the specs list, and if the values are higher than 250 µV/m, the transmitter is not compliant with Part 15

Since most manufacturers don’t publish field strength in the specs, you can try looking for the advertised range. Legal transmissions have a very short range not exceeding 200ft or 61 meters. If the advertised range is longer than 200ft, the transmitter is probably not compliant with Part 15. If the max range is a few miles or kilometers, the transmitter is definitely not compliant with Part 15. 

Finally, legal FM transmitters don’t have high output power. The max output power is usually equal to or lower than 0.1W. This doesn’t guarantee compliance with Part 15, but it can be a good indicator of an illegal transmitter. If the advertised power output is 5W, 7W, or 15W, the FM transmitter is definitely not legal for license-free FM transmissions.

An FM transmitter compliant with Part 15 can only operate on frequencies between 88.1MHz and 107.9MHz. If the range is larger than that (like 87-108MHz), it’s definitely not compliant with the Part 15 regulations

Finally, if the FCC ID is not engraved on the device or printed on the sticker and glued onto the transmitter, the transmitter is not compliant with the Part 15 regulations. Sometimes, you can find the FCC ID in the specs, as well. 

Example of an illegal transmitter’s specs – this transmitter is not compliant with the FCC’s Part 15 regulations

Example of an illegal transmitter’s specs – this transmitter is not compliant with the FCC’s Part 15 regulations

Option 2 – Check the FCC ID (Harder but Much More Reliable Option)

Besides checking the specs, you can check the FCC ID if you manage to find one in the specs. This is much more reliable than checking the specs. 

If you don’t find the FCC ID in the specs or if there’s no FCC ID engraved on the transmitter or printed on a sticker and then glued onto the transmitter, it’s safe to assume that a device is not compliant with Part 15 of the Title 47. 

If you find an FCC ID, you have to check it in the FCC database. Seeing a random string of letters and numbers named FCC ID doesn’t automatically mean that the ID number is valid. Some sellers or manufacturers actually used to fake the FCC ID in the past. 

I will guide through the whole process. 

First, visit the FCC ID search page on the official FCC website. An alternative webpage you can use to check the ID is

On the ID search page, you will have to enter the transmitter’s FCC ID (the one you found in the specs or on the device). Before entering the ID, read the instructions below the search form.

While an FCC ID is just one long string of numbers and letters, you will have to divide it into two parts – Grantee Code and Product Code

The Grantee Code consists of three or five letters and numbers. Grantee Codes that start with a letter, consist of three characters. Grantee codes that start with a number ranging from 2 to 9 consist of five characters. If the FCC ID you found starts with 0 or 1, you should know immediately that the code is fake

The remaining portion of characters following the Grantee Code is the Product Code. 

Enter the transmitter’s FCC ID on this page

Enter the transmitter’s FCC ID on this page

If the transmitter was actually certified by the FCC, after you click on the Search button, you will get search results similar to those in the image below. 

FCC ID Search Results

FCC ID Search Results

The search result will display all the essential information about the manufacturer and transmitter. To see the actual Grant issued by the FCC, click on Grant Display

FCC Grant – This proves the FM transmitter is compliant with the FCC’s Part 15

FCC Grant – This proves the FM transmitter is compliant with the FCC’s Part 15

WARNING: Some FM transmitters are certified by the FCC, but not for unlicensed use. If you enter their FCC ID, you will get similar results to those shown above, but when you open the Grant, you will see that they are not compliant with Part 15. Instead, they can be compliant with Part 73 (see the images below).
RETEKES TR510 – FCC-certified FM Transmitter

RETEKES TR510 – FCC-certified FM Transmitter

The transmitter is compliant with the FCC’s Part 73 regulations (not Part 15) – it can’t be used for license-free operations

The transmitter is compliant with the FCC’s Part 73 regulations (not Part 15) – it can’t be used for license-free operations

Can FM Transmitters Compliant with the Part 15 Be Operated Illegally?

Unfortunately, yes. Some FM transmitters have adjustable RF power output and can have a range longer than 200ft at max power output. They comply with the Part 15 regulations when used at lower power outputs. So, make sure to check the range and adjust the output before you start transmitting. 

I have also seen some reviews of US-made FM transmitters compliant with the Part 15 regulations that actually have a much longer range than the one defined by the FCC. For some transmitters, the range exceeded 1,500 feet, which is kind of amazing but also illegal. 

What About AM Transmission? Is AM Transmission a More Convenient Option?

As you have seen, license-free FM operations in the US are highly restricted. The situation is slightly (but not significantly) better with AM operations. 

Rules for license-free operation on the AM band are regulated by Part 15, Section 219. According to this section, the max allowed input power to the final radio frequency stage is 100mW, and the max allowed transmission line length is 3 meters. The transmission line length is the combined length of the antenna and the ground lead. 

Also, Section 15.219 requires 20dB attenuation below the level of the unmodulated carrier for all license-free emissions within the AM band. 

Like the FM Transmitters, AM transmitters used for license-free operations must accept any interference coming from other operations within the same band.

Section 15.219 of the Title 47

Section 15.219 of the Title 47

AM Transmitters compliant with Part 15 regulations can, under ideal conditions, have a much longer range than Part 15 FM transmitters. In some cases, the range can exceed 1 mile. Have in mind that the range depends on many factors including antenna, time of day, interference from adjacent channels, etc.

The biggest issue you may experience with AM transmitters is more noise compared to FM transmitters. They are more susceptible to noise induced by all kinds of electronic devices.

When looking for an AM transmitter, you also have to pay attention to the FCC certification. The transmitter must have an FCC ID and be compliant with Part 15 regulations. Most importantly, the transmitter should meet the requirements from section 15.219.

Some of the most popular AM transmitters for license-free use are ChezRadio Procaster and Rangemaster AM1000.

Frequently Asked Questions

  • Question: Is it legal to use an FM transmitter without a license? 
  • Answer: Yes, but the restrictions are significant. License-free use is regulated through sections 15.109, 15.209, 15.231, and 15.239. The max. allowed field strength for an unlicensed FM transmission is 250 µV/m. In practice, this means that the max allowed transmitting power output should be 0.1W or lower, while the max range should not exceed 200ft. 
  • Question: How far will a 1-watt FM transmitter go?
  • Answer: On average, a 1W FM signal can reach 1km (0.6 miles). The range can be even longer under ideal conditions. 
  • Question: How to increase the FM transmitter’s radio signal strength?
  • Answer: Some FM transmitters have adjustable RF power output allowing you to easily set the signal strength. If your FM transmitter doesn’t have adjustable power output, your only option is to modify it, but that would void the FCC certification and make the transmitter illegal for license-free use.
  • Question: How far will a 15W FM transmitter broadcast?
  • Answer: On average a 15W FM transmitter can have an amazing range of up to 5km (3.1 miles). The range can even be longer, depending on the conditions and interference. Such powerful FM transmitters are not allowed for license-free use. 
  • Question: How far will a 0.5W FM transmitter go?
  • Answer: The average range of a 0.5W FM transmitter is approx. 300 meters (980ft). Even 0.5W FM transmitters are not allowed for license-free use in the US because their range is significantly longer than the range of Part 15 transmitters (which is approx. 200ft). 


I hope this detailed guide helped you understand the legal regulations restricting the use of FM transmitters without applying for a license and find the best Part 15 FM transmitter for your church. 

If there’s something else you want to know about FM transmitters or legal regulations, or if you need a piece of advice regarding a specific FM transmitter setup for your church, feel free to leave a comment below.

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