This is one in a series of articles about trends in STLs for radio.
A few weeks ago, Josh Bohn visited a station still using a TFT 950 MHz STL transmitter that was made in 1988. “That’s before my wife was born,” Bohn remarked.
A lot has changed in 37 years. Bohn’s work as CEO of MaxxKonnect often focuses on delivering all kinds of audio and telemetry over IP — even across limited connections. That capability, he noted, is a relatively recent development.
The 400 kbps bandwidth that MicroMPX was originally designed to use works well over non-metered fiber, cable or DSL, Bohn said. That level of data usage would burn through over 400 GB per month. That translates into big dollars for data consumption.
“To say that’s a dealbreaker for 99% of customers would be putting it mildly,” he said.
That’s where the insight of Hans van Zutphen at Thimeo has proven important. Van Zutphen has continued to advance the MicroMPX compression algorithm, which now enables MPX delivery at much lower bitrates.
Bohn praised the work, noting that his parent entity Triple Helix Technologies has partnered with Thimeo to leverage the technology.
“The result is not needing a fiber link to support MPX over IP,” Bohn said, “thanks to compression that doesn’t compromise audio quality.”
Which flavor is for you?
With cloud-based air chains growing in popularity, Bohn emphasized that having multiple IP connections at a site will become the norm. As with anything, IP links can and will fail. For cloud-based operations, Bohn recommends a reliable backup, such as an LTE or robust satellite connection.
He practices what he preaches: He owns two stations in Alabama, 1490 WIEZ(AM) and 94.7 W234DN Decatur, and operates 1320 WENN(AM) Birmingham and its 92.3 translator (via an LMA) — both of which use internet-based IP STLs. These setups allow him to run codecs over different providers and services, with full visibility into camera and security systems.
“We’re using a mix of our MaxxKonnect Satellite internet, as well as MaxxKonnect LTE service for these sites. That way, if one of the diverse delivery methods fails, the other will still be up. You can’t get physical-site security data with a 950 MHz link,” he said. “There’s no return path.”
With his experience in the industry, Bohn is familiar with the myriad methods of air chain transport. More than one solution, naturally, can handle MPX.
He recently used a MicroMPX link between two PCs with the AudioScience U.192 MPX USB soundcard, which is capable of outputting analog and digital MPX audio to feed a transmitter. That’s attractive particularly to smaller stations.
“Everyone is looking for cost value at this point,” he said.
High-quality audio codecs can also get the job done, and MPX over IP codecs, including those supporting MicroMPX, are widely used.
The perfect slice of spectrum
In a Radio World interview in 2023 on the subject of STLs, Bohn estimated that he had sold only three point-to-point links in the two years prior.
Bohn preached in our recent conversation that radio must evolve, even after decades of success using traditional methods.
But just like the station he visited recently, he also realizes there are still many broadcasters in the U.S. — perhaps in the thousands — that have point-to-point 950 MHz STLs installed, either as their primary or as backup for delivering studio content to the transmitter.
“The 950 MHz range is the perfect band,” Bohn said. “It’s high enough in the spectrum to carry both audio and data, but also resilient in weather conditions like fog and rain. With a big enough antenna and enough height, you can get about 50 miles of range.”
In fact, MaxxKonnect recently released the UST/USR-950 analog STL system, which debuted at the NAB Show. Bohn believes it’s ideal for small- and medium-sized stations.
But in today’s environment, any STL solution needs to do more than just relay audio.
“The new UST transmitter and USR receiver has browser-based control on both ends,” Bohn said. “You can log into the transmitter and receiver remotely. It also supports SNMP and has email alerts for silence, squelch, forward-power failures and other parameters.
“These are all things analog STLs have never had,” he added.
While it’s unlikely that a cluster deep into an IP-based revamp would revert to legacy systems, Bohn sees the 950 MHz STL as a suitable backup even for stations with fiber or PTP IP systems.
“If your station has an existing 950 MHz license, why not use it?”
The plusses and minuses of satellite
For a long time, the industry avoided satellite-based IP delivery. But that’s changing.
Bohn said Starlink is often suitable for audio delivery. MaxxKonnect has a partnership with Starlink and ViaSat to provide high quality satellite-based IP service to broadcasters and other industries.
Some of these systems use the Ka band, which can experience weather-related signal fading. But Bohn said today’s dropouts aren’t nearly as disruptive as they once were.
“Everyone still remembers satellite TV from the early 2000s,” he said. “It’s not nearly that bad anymore.”
Starlink uses low-earth orbit, while ViaSat is geostationary, making Starlink somewhat less susceptible to weather interruptions. At one ViaSat-equipped client site using Ubiquiti Dream Machines, Bohn reports average speeds of 75 Mbps down and about 7 Mbps up.
“That’s plenty fast enough to deliver multiple audio streams,” he said.
Some stations have expressed concern about support with satellite services, particularly Starlink.
“If you buy Starlink directly, your only real support is an e-mail address,” Bohn noted. “But if you go through a partnered reseller like us, you’ve got a real support resource.”
One technical caveat: Starlink does not support IPv4 addresses, which are still vital in many broadcast applications for remote access.
“You better have someone who understands how to set up a robust VPN on a WAN — and it can’t rely on a public static IP address,” Bohn warned.
Security concerns around Starlink have also been raised. Still, there are plenty of success stories — such as Starlink deployments restoring connectivity after natural disasters in Asheville and Tampa last fall.
“That’s the biggest benefit to satellite: It’ll work pretty much anywhere you can see the sky, no matter how remote” Bohn said.
Radio-centric support
MaxxKonnect offers a bundled package that includes satellite and unlimited LTE failover at a fixed monthly rate. At one station in Houston, the satellite modem failed — but the staff didn’t even notice, Bohn said, as the system had automatically switched to LTE.
MaxxKonnect was able to dispatch support and replace the modem quickly.
Regardless of the delivery method, Bohn encourages broadcasters to work through broadcast knowledgeable providers.
“There are all these different ways to get connectivity to your sites,” he said, “but does anyone at those companies actually understand what you’re trying to do?”
Working directly with cellular carriers may introduce other complications. Many budget cellular options use “roaming SIMs” which often have IP addresses originating from other countries.
“If your IP address originates from Belgium, well, that can cause a problem — there’s a lot of geo-fencing and IP restriction going on due to security risks,” Bohn said.
With so many options, the array of audio delivery choices can feel overwhelming. But Bohn encourages broadcasters to start by evaluating their needs.
“The flexibility of IP control and monitoring is something everyone’s implementing now,” he said. “But the legacy 950 is still a well-built, reliable option — and we’re supporting it.”
