A radio lifeline, relied upon and enjoyed by generations of Southern trampers, hunters and emergency services, is set to fall silent at the end of this month (Jun 2023).

Canterbury Mountain Radio's (CMRS) 55-year-old South Island high frequency service will cease on Thursday (30 Jun).

The service's demise is blamed on dwindling sales, fewer volunteers and the preference for more mobile satellite technologies.

CMRS retailer and Fiordland Search and Rescue volunteer Stewart Burnby said his experience with mountain radio started about 30 years ago as a radio hire agent for firstly Southland Field Radios, then CMRS.

"I ended up with 49 radios for hiring out, which during the roar used to be all out," Burnby said.

Burnby said he had started broadcasting 8.30am skeds (amateur radio jargon for scheduled or prearranged contact) about 5-6 years ago, after the retirement of one of the service's regular operators.

The CMRS system had become quite sophisticated with some radios now able to make phone calls and also be monitored by computer, he said.

However, the increased preference for Personal Locator Beacons (PLB) and SEND satellite systems had seen mountain radio's popularity wane.

"In the last couple of years I'd be lucky if I had six radios hired out," Burnby said.

Southern Lakes Helicopters safety manager Richie Hunter said it was the end of an era and it was sad to see it close.

He said Mountain Radio had been the key link for Search and Rescue and had given a huge amount to the outdoor community.

"It was the only way for calling for help or getting a message out," Hunter said.

"It worked very well and probably ultimately, it's responsible for saving a lot of lives."

Hunter said it also used to be fun with everyone crowding around the mountain radio, running out the aerial and turning it on and listening to the broadcast of the weather above the static noise.

"If you hung in there long enough, you'd actually hear all the other field parties and you'd hear what other people were up to."

"And you know, you'd get to know what people were doing."

Hunter said the implementation of a personal locator beacon was now the quickest, fastest response and most accurate for an emergency.

He also said they were seeing a lot more hunting parties using SEND devices, like the Garmin inReach, which allowed communication through text message or email or a satellite link.

However Hunter said that while the advanced SEND technology was good, reliable and user friendly, there were still times where they didn't work.

"There are times when there might be delays of multiple hours, and in some cases, we may not necessarily receive every single message that the person transmits."

Hunter said there could sometimes be room for confusion with text messages so it was always important that every text message received was positively responded to.

He said he also found satellite phones good when he was in the field "because when I talk to you, I know that you understand what I'm saying".

"[However] the issue of the satellite phone call, is that they cut out. And depending on where you are, what terrain is obscuring your coverage and the way the satellites work, it might take me multiple phone calls to to get my message across to you," he said.

Burnby and Hunter recommend carrying both a PLB and SEND device.

Stewart Burnby will make the final broadcast on South Island mountain radio at 8.30am, Friday 30th June.