The rush is on to check if thousands of mobile phones and other electronic devices embedded in farm equipment will stay working when 3G networks shut down in the next six months.
Even some older 4G phones may not be adequate for calls, including triple zero emergency contacts, when 3G shuts off.
Farmers have already been caught out with service disruptions and telemetry failures in gear which they understood should not have been impacted by the changes.
Telstra will turn off its 3G network on June 30 and Optus follows in late September. Vodafone shut its service in January.
However, rural dwellers are worried the telecommunication network upgrades to provide equivalent or better 4G or 5G services may need to be supported with extra booster kits or replacement gear and modifications to maintain their signal strength.
"For various reasons people are asking why this upgrade is already feeling like a downgrade," said NSW Farmers president, Xavier Martin.
Perplexed that some farmers were experiencing telemetry equipment problems well before the Telstra or Optus networks had shut down, Mr Martin said producers from North West NSW to the Riverina were reporting equipment failures.
In some cases signal strength declined when 5G services had been switched on in their district, providing insufficient capacity for equipment to operate.
One example involved a hay producer who now feared he would lose the chance for a final lucerne crop cut for the season because his irrigation booms suddenly couldn't receive adequate signal to operate.
In another case, relatively new irrigation pump meters could not automatically report water extraction rates.
Other farmers were angry and frustrated about extended service interruptions to current 3G and 4G services lasting for a week or two as telcos modified their networks in preparation for the looming deadlines.
Although only about one per cent of Australia's mobile phone traffic relies on the 3G spectrum, the 3G network's coverage also drives the connectivity behind a wide range of farm equipment activation and information activities.
Typical gear using telemetry data might include electric fences and water tank monitoring devices, soil moisture and temperature sensors, irrigation rigs and pumps, security cameras, dairy equipment and crop spraying rigs.
Non ag-specific uses for the 3 million 3G-compatible phones and devices used Australia-wide range from EFTPOS machines to about 200,000 medical alarms and related household health monitoring gear.
The digital 3G network began operating in 2006, replacing the voice-only analogue and hybrid CDMA service in 2008.
Now it is being repurposed so the underutilised frequency can accommodate 4G and 5G spectrum services with faster, wider bandwidth to handle big data download demands.
Disruptions likely
While no Telstra services have been switched off yet, the big telco has warned some disruptions to its regional network were required as 3G equipment was replaced or existing 4G towers upgraded with new technology and better designed antennas.
Telstra, with 99 per cent coverage of the Australian population, including the biggest geographic footprint, has almost 12,000 mobile towers servicing 3G, 4G and 5G networks in regional and metropolitan areas.
Just 2pc of those towers, mostly in relatively remote areas, still operate 3G services.
"Unfortunately, while we're doing upgrade work in specific areas these disruptions are extending over several days at a time," said Telstra's southern NSW regional manager, Chris Taylor.
Telstra insisted anybody making mobile phone calls on the 3G network today should receive the same quality service, or better, on 4G by June 30, assuming their handset was not more than five or six years old.
Mr Taylor said, however, even some recently acquired handsets may need to have their 4G settings unlocked.
Similar setting variations could also be needed where customers currently relied on signal booster kits for 3G connectivity in poor reception or black spot areas.
In fact, they may need to replace their amplifier and/or antenna with new booster gear, potentially at a cost of about $1200, plus installation charges.
"We'd recommend using somebody who is appropriately trained to do any installation to improve the phone signal, or any telemetry equipment upgrades," he said.
Check your gear
Meanwhile, telecommunications companies have urged farm sector customers to check with their suppliers about whether any machinery or monitoring equipment using telemetry transmissions may be impacted by the 3G shutdown.
The same applied to households with medical monitoring equipment, including CPAP machines for sleep apnea sufferers.
While recently purchased equipment was unlikely to be impacted, in some cases an upgrade could simply involve buying a new, relatively cheap, SIM card.
Aside from switching to a 4G telemetry signal, sensor monitoring gear could also make use of non-voice narrow bandwidth services, which were well placed to send and receive data.
However, NSW Farmers' Mr Martin said there appeared to be more explanation needed, especially around the problem of reduced signal strength on farms in some localities where 5G upgrades had already replaced 3G or 4G.
"The 5G signal doesn't appear to be as strong, and is likely to be limited to towns or along highways," he said.
"There also seem to be other issues with signal strengths being less reliable, too."
What's now outdated
The Australian Mobile Telecommunications Association has listed 25 of the most-used phones and related devices which will not work after the 3G shutdown.
These devices include the iPhone 5, 5C and 5S; Google Pixel 2 XL; Huawei's E5251s-2, E5331 and Y6 Prime; Nokia 301; Optus X Smart; iPad Air, Retina and iPad mini, and Samsung Galaxy S5.
Some smartwatches, although 4G compatible, may only work on a limited set of 4G spectrum bands and thus could have reduced mobile network coverage, including Apple Watch Series 3, 4 and 5, and the Samsung Galaxy Watch.