Fully Featured
COBALT  Low Power FM Transmitter
cobalt 300

Choose the best transmitter for your LPFM station.

As a smaller broadcaster, usually on a tight budget, making the wrong decision about what transmitter to buy could mean your LPFM station fails before it’s even got off the ground.

Aqua Broadcast is at the forefront of designing and manufacturing FM transmitters for broadcasters worldwide who are regularly choosing Aqua Broadcast for their FM Transmitters.

We have your back!

Whether you are starting a new LPFM in the application filing window in November 2023, or looking to update your older LPFM Transmitter, don’t make the wrong decision about what transmitter to buy, Aqua Broadcast can help you.


You can only use a transmitter that is certified for LPFM use which has an “FCC ID” label on the transmitter. If it does not have the FCC ID label on it, it can’t be used for LPFM. All Aqua Broadcast COBALT FM transmitters from 10W to 1000W have an FCC ID, they were all tested and verified by an FCC approved Lab and certified for use.

Cobalt c-300 LPFM transmitter

How will the COBALT C-300 ensure LPFM success?

It’s a 300W FM stereo transmitter obviously - but it’s so much more. It’s a fully featured LPFM broadcast solution DESIGNED FOR YOU! - With its unique Linux based operating system, and clean Digital Modulation (DDS) on all COBALT Transmitters that delivers consistent quality and low distortion.


More connections than ever

Inputs and outputs include 2 x MPX IN/OUT, Analog, AES/EBU, Digital MPX (AES192), ITU-R BS412.9 Limiter, Ethernet, USB, GPIO, GPS Sync with built in SFN capabilities.

Audio Processing - for FREE

The COBALT has got a 4-band processor built inside the transmitter. This 4 band FM digital audio processor has 21 Factory presets to get you sounding great right out of the box letting you make an impact in your market with the sound that the transmitter delivers. Still want to use your own favourite processor? No problem – the complete I/O package with routing internally easily allows for that too!

Cobalt c-300 LPFM transmitter board

Connect remotely - from anywhere!

The COBALT C-300’s web remote control provides ease of monitoring and with configurable email alerts, you’ll never not know if there is a problem with your transmission. RS232, Telnet and SNMP v1, v2c, and v3 give your technical guys legacy and modern communication protocols to keep them happy. SNMP v3 is the latest protocol, and COBALT Transmitters are the only ones available with this. The COBALT C-300’s configurable alarms and triggers allow a multitude of interfacing possibilities to other manufacturers’ products. The COBALT C-300’s connections future proof your investment.

Listen - from anywhere!

Need to monitor your audio remotely? We got you covered with that too, simply click the listen function and hear either the input OR the output of the Transmitter. This saves you a bunch of money, so you don’t need to be any external streamer, wherever you are, with any web enabled device – the COBALT is accessible.

Optional extras - do you want even more?

How about a second PSU for redundancy, that has its own AC input, run on the same line or even to a UPS on the second supply.

Add Dante / AES67 to your Transmitter with a simple module, compatible with all relevant 3rd party products that support the format.

Get the 5 Band Ultra processor for that wow factor, high performance and modern presets at a price that sends the competition reaching for the handrail.

MicroMPX is an STL (studio-to-transmitter link) codec that transports a full FM composite MPX signal, including pilot and RDS, at a bitrate of only 320 kbit/s, with perfect peak control. Using MicroMPX you can generate your signal completely in your studio (separate PC lisence required) and easily send it to COBALT transmitters.



We have you covered now and into the future. Right out the box with more than ever - we heard what you wanted and delivered!

DDS Modulator
Digital MPX (AES 192)
Linux O/S
MPX Limiter (BS.412.9)
RGB Screen
SFN Ready
4 Band Audio Processor
SNMP v1,v2c,v3
RDS Encoder
HTTP/S Ethernet


We have you covered now and into the future. Right out the box with more than ever - we heard what you wanted and delivered!

Dante / AES 67
5-band Audio Processor
Dual Power

Why do I need 300 watts for a 100 watt licensed LPFM station?

If you want to broadcast the best signal possible for your listeners (greater coverage) you’ll probably want to use a circular polarized antenna to enable you to broadcast in both horizontal and vertical planes. Without getting too technical, this helps listeners receive your broadcast better no matter where they are, including in their cars and homes. You can’t always control which way your listeners position their antennas so it’s always best to pick the right antenna to maximise performance for ALL your listeners.

When you want to connect an FM transmitter to a circular polarised, you’ll need to provide the antenna with double the RF power to get the same power broadcasted horizontally and vertically. The cables that connect the transmitter to the antenna will have losses (lose you RF power), so if you are serious about how well your signal broadcasts, and you really want to run at your full licensed power, you’ll need to be looking at a transmitter that can deliver at least 250 watts - no problem with the COBALT C-300 from Aqua Broadcast.

Support and care when you need it

We understand the importance of delivering comprehensive aftercare and support to our valued customers with always available and affordable parts prices.

Our responsibility extends well beyond your initial purchase, and we are dedicated to ensuring a seamless and satisfying ownership experience with our FM transmitters.

Let’s start with our team of knowledgeable and skilled professionals who live and breathe the intricacies of our FM transmitters. With fast and responsive communication, our customer support team is available to answer your questions, provide troubleshooting guidance, and offer personalized solutions tailored to you. From full repairs, software updates, comprehensive documentation, user manuals, and online resources to empower you with the knowledge needed to maximize the capabilities of your Aqua Broadcast FM transmitter.

Parts both sides of the pond.

We keep parts always available and at affordable prices both in the USA and at the factory – using fast shipping services. They are equipped with the technical expertise to assist you with any issues that may arise during the lifespan of your transmitter.

We also offer efficient issue resolution to minimize any disruptions to your broadcasting operations. Our streamlined processes and diligent support staff ensure that any technical problems are resolved swiftly and effectively, allowing you to resume your broadcasts with minimal downtime.

Free Software updates

Your broadcast adapts and evolves constantly. As we think of new and cool ways of doing things with our transmitters, we quickly add them and release firmware updates.

Cobalt c-300 LPFM transmitter screen

Full sales support in the United States

All Aqua Broadcast products are sold in the US by SCMS Inc out of North Carolina.

With 47 years of experience, there isn’t another company better placed to look for ALL of your LPFM equipment needs than SCMS. From the Transmitter, EAS system, Antennas, Studio products and everything in between, SCMS offers it all.

SCMS staff have without doubt the most experience with LPFM products out there. With full sales and support backup from the Aqua Broadcast factory.

If you need them to, they’ll assist you with studios, remotes, playout systems and much more.

Cobalt c-300 LPFM transmitter back