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User Report: GatesAir Networking Supports All-Digital STL

Intraplex equipment helps overcome challenges from weather and atmospheric conditions

The author is president of NIA Broadcasting in Jacksonville, Fla.

NIA Broadcasting has long understood the value that HD Radio can bring to a broadcaster’s audience and brand. Following successful HD Radio launches at two of our FM stations, we turned our attention to WYKB(FM), a classic country radio station serving the greater Jacksonville market.

The WYKB HD Radio launch was part of a complete system upgrade covering the transmission facility and STL connectivity. For the latter, we transitioned from a pure analog microwave STL link to a hybrid GatesAir Intraplex networking system with a digitized microwave STL, IP codecs, and redundant streaming capabilities. The complete system also includes a new GatesAir air-cooled transmitter equipped with HD Radio Gen4 transport and processing systems.

The new STL architecture is built to withstand local atmospheric conditions that create unusual operating challenges. This includes tropospheric inversions, a rare temperature-related phenomenon that can create waveguide-like reactions within radio signals. Those reactions can cause the WYKB signal to suddenly be heard in markets far beyond our region.

While tropospheric inversions only happen several times each year, it is a problem that requires attention. We not only needed an STL system that could carry HD and FM program audio (as well as program-associated data), but one that also consistently problem-solved any negative inversion effects.

Working with GatesAir, we designed an interesting solution that addresses those two key requirements while adding greater redundancy and resiliency. And, we achieved this in a way that retained our existing Intraplex HD Link 950 MHz STL, leveraging its integrated IP channel option to carry HD Radio data.

GatesAir Intraplex IP Link MPXp
GatesAir Intraplex IP Link MPXp

The HD Link microwave connection is spliced with an Intraplex IP Link MPXp codec, using its digital AES192 transport functionality to transport HD and composite FM signals over the public internet. A GatesAir IP Connect device transports the E2X (exporter-to-exciter) data to the transmitter over this same connection, with all systems leveraging GatesAir’s Dynamic Stream Splicing software for redundancy. This software ensures that each connection can borrow packets from each other to repair streams, and is the secret sauce to the new system’s rock-solid reliability.

It’s important to stress that the two transport streams are active 24/7 and almost act as a single, combined primary link (versus main/backup), as the dual IP streams are technically spliced together. This is critical in a region like northern Florida, where long-term power and service outages are possible. There is also the very real possibility of wind-damaged STL dishes from hurricanes and tropical storms. If we have a hit on the STL or the public internet, the audience will not notice, supporting GatesAir’s claim as a “hitless” solution. There is no glitch, no on-air hiccup, and no switching between stream required.

This is also true when potential problems are self-made, such as when we recently changed IP addresses on our fiber line. Traditionally, that work would have taken place at 3 a.m. with the station off the air. With Dynamic Stream Splicing, we handled this in daylight with the station on the air — and with no audible effect on the listening experience.

Using this configuration, we can also maintain the highest possible audio quality. While the IP Link MPXp offers an analog composite MPX output, we opted for AES192 to keep everything purely digital and uncompressed. The HD Link is itself a broadband system that natively passes uncompressed audio. The upgrade effectively ends all analog program signal transport to the transmitter site.

GatesAir Intraplex HD Link digital STL
GatesAir Intraplex HD Link digital STL

As technical as the new system sounds on paper, the new Intraplex system was configured and functional within 24 hours. This includes new IP Link MPXp codecs and HD Link digital radios at the studio and transmitter sites, as well as the studio-based IP Connect device.

The IP Connect is vital to the operation, as it creates an IP path to reliably move HD Radio data from studio to transmitter over both systems. That data originates from GatesAir’s Flexiva FMXi 4g, an embedded HD Radio solution that combines the traditionally separate “Importer” and “Exporter” functions. The FMXi 4g also builds HD Radio diversity delay into its platform, so FM and HD time alignment is handled before all multiplexed digital signals leave the studio. At the transmitter site, the Flexiva FAX exciter amplifies all signals within the Flexiva FAX10 air-cooled transmitter, with HD Radio sidebands set to –14 dB.

GatesAir FMXI 4G Embedded HD Radio Program Importer/Exporter
GatesAir FMXI 4G Embedded HD Radio Program Importer/Exporter

The support from GatesAir continues to be top-notch. Like the Intraplex systems, they are always available and continue to respond quickly when we have questions months after the installation. That is clear evidence of their dedication to customer service.

Radio World User Reports are testimonial articles intended to help readers understand why a colleague chose a particular product to solve a technical situation.

For information, contact Keith Adams at GatesAir in Ohio at 1-513-459-3447 or visit