Client: Coromandel’s CFM (Radio Coromandel Ltd)
Location: Whitianga and the Coromandel Peninsula
Timeline: 2018 onwards: Whitianga studios 2018, mobile studio 2019, Wheatstone upgrade and Thames studio 2020, network and single frequency network 2021, ongoing development
Services: Studio design and build, Wheatstone systems, FM single frequency network (SFN) design, transmission, IP and microwave linking, network resilience, ongoing engineering support
Overview
The Coromandel Peninsula is one of the hardest places in New Zealand to cover with FM radio. Steep bush-clad ranges run down its spine, and its towns are scattered around a long, broken coastline. Conventional networks need a different frequency for almost every valley, and listeners driving the coast have to keep retuning.
CFM, Coromandel’s own local station, set out to do better. Working with CFM’s owners, John and Lynda Grant, Southern Broadcast has built CFM’s studios in Whitianga and Thames and engineered one of the most technically advanced regional radio networks in the country, including a synchronised single frequency network that covers the east coast of the peninsula on one frequency.
Stage one: the Whitianga studios (2018)
In August 2018 we began building CFM’s new studios in Whitianga, taking bare rooms back to the framing and rebuilding them as a purpose-built on-air studio and technical centre.
The technical rack brought together broadcast-grade processing, monitoring and distribution: a Wheatstone FM-55 multi-band processor, WorldCast APT IP codecs to feed the transmitter network, a Tieline codec for outside broadcasts, and DEVA off-air and silence monitoring with automatic backup audio, so the station stays on air even if the studio feed is lost.
By November 2018 the on-air studio was complete, built around an Audioarts AIR-4 console with Electro-Voice RE320 microphones on Yellowtec m!ka arms.
A studio on wheels (2019)
In 2019 we fitted out CFM’s caravan as a fully working mobile studio, with its own console, playout, microphone and network rack. It takes the station out to events around the peninsula and doubles as a backup studio: when the Whitianga technical centre was rebuilt in 2021, CFM’s live shows went to air from the caravan.
Stage two: Wheatstone IP-12 (2020)
In February 2020 the on-air studio was upgraded to a Wheatstone IP-12 digital console on the WheatNet-IP network, giving CFM a fully networked studio with every source available at the touch of a button.
The Thames studio (2020)
In March 2020 we built CFM’s second studio in Thames, giving the station a home on the western side of the peninsula. It follows the same approach as Whitianga: an Audioarts AIR-4 console, Electro-Voice RE320 microphones on Yellowtec m!ka arms, and a height-adjustable desk so presenters can work standing or seated, with guest positions around it. The studio is networked back to Whitianga and the transmission network, so shows can go to air from either town.
One frequency for the whole east coast
CFM’s transmission network is where the engineering really stands out. A competing network needs around a dozen frequencies to cover similar ground. CFM covers the entire east coast of the peninsula on a single frequency, 95.1 FM.
How it works. CFM’s Whitianga transmitter site is the primary site and the heart of the single frequency network (SFN). From there, programme is carried over CFM’s own IP and microwave network to transmitters at Pauanui South, McBeth Road and Tokatea, linking through the Tairua Lookout hub. Every site runs a WorldCast Ecreso FM transmitter fed by WorldCast APT codecs, with GPS timing keeping every transmitter precisely in step, so where their coverage overlaps listeners hear one seamless signal instead of interference.
The west coast too. On the west coast, where 95.1 couldn’t be used, the same programme goes out on 94.0 FM from Rataroa, fed by the same network. Every site also has a backup studio-to-transmitter link.
The result. No “mush zones” where signals clash, and no need to retune: listeners can drive the length of the coast and stay with CFM the whole way. WorldCast featured CFM’s network as a user story in Radio World’s 2022 Buyer’s Guide.
Building the transmission network
Several of CFM’s sites have been built from scratch on bare hilltops, from poles and huts to antennas, links and transmitters.
Rataroa (2019). In August 2019 we raised a new pole and site above the Hauraki Plains to carry CFM on 94.0 FM for the west coast, with the site completed in early 2020.
The Whitianga transmitter site (2020). The primary site is where the single frequency network originates. In May 2020 we carried out antenna work on the site’s pole. Its rack carries the station’s processing, RDS, monitoring and WorldCast APT codecs, feeding the synchronised transmitters around the coast.
Tokatea (2020). High in the ranges above Coromandel town, Tokatea carries CFM’s signal and links on a shared monopole.
McBeth Road (2021). In March 2021 we built a new site at McBeth Road to extend the single frequency network south, with a new pole, equipment hut, FM antennas and microwave link.
Built to stay on air (2021)
In March 2021 we rebuilt the Whitianga technical centre around a new network rack, with redundant firewalls and automatic failover between fibre, VDSL and 4G connections. The whole network is monitored and managed remotely, and it was designed with civil defence in mind: in a region prone to storms and road closures, CFM’s ability to stay on air matters.
Still growing
The network has kept evolving ever since. Southern Broadcast has continued to extend and upgrade it, from SFN codec and firmware upgrades to new transmitter sites and a new microwave link. In August 2026 we launched CFM on 92.2 FM in Waihi.
Key facts
- Purpose-built on-air studio and technical centre in Whitianga, 2018, upgraded to a Wheatstone IP-12 in 2020
- Caravan mobile studio for events and backup broadcasting, 2019
- Second studio in Thames, 2020
- Synchronised FM single frequency network covering the east coast on 95.1 FM from sites at Whitianga, Pauanui South, McBeth Road and Tokatea
- The same programme on 94.0 FM from Rataroa for the west coast, where 95.1 couldn’t be used
- Launched on 92.2 FM in Waihi in August 2026
- WorldCast Ecreso transmitters and APT codecs with GPS synchronisation at every site
- CFM’s own IP and microwave network, with backup studio-to-transmitter links
- Redundant firewalls and fibre, VDSL and 4G failover at the Whitianga studios
- Featured by WorldCast in Radio World’s 2022 Buyer’s Guide
Southern Broadcast Ltd is Wheatstone’s New Zealand partner and a broadcast engineering company providing studio, RF and transmission design, installation and support to broadcasters across New Zealand and the Pacific.
Want better coverage from fewer frequencies? Talk to Southern Broadcast about single frequency networks, transmission and studio design.