Previous 2600-megahertz frequency usage tests showed no sign of interrupting the signalling system of mass transit rail services, says the National Broadcasting and Telecommunications Commission.
The NBTC held a meeting yesterday with the Department of Rail Transport (DRT), the Mass Rapid Transit Authority of Thailand, Bangkok Expressway and Metro Plc (BEM) and Bangkok Mass Transit System (BTSC), as well as Advanced Info Service (AIS).
BTSC operates the skytrain service, while BEM runs the Blue and Purple electric train lines.
The meeting agreed to set up a panel to continue monitoring whether use of the 2600MHz range through 5G service would affect rail service in the long run.
AIS has been testing and collecting data for approaches to ward off signal interruption since late 2019, said NBTC secretary-general Takorn Tantasith.
AIS launched 5G services on the 2600MHz spectrum range it won at the Feb 16 auction.
Tests intensified throughout all skytrain routes after last month's 5G spectrum auction.
On Feb 25, the DRT, BTS and AIS jointly conducted a test at Siam skytrain station. The results showed no impact on rail services.
Wasit Wattanasap, head of nationwide operations and the support department at AIS, said the company also worked with BEM to conduct tests and prevent the spectrum impinging on rail operations.
The results were also reported to the NBTC at the meeting yesterday, Mr Wasit said.
"We want people to feel confident," he said.
Sorapong Paitoonphong, director-general of the DRT, said BTS will install upgraded spectrum filter equipment, replacing the existing equipment located at 700 spots, within the next five months to ensure that spectrum usage doesn't affect skytrain operations.
Despite reporting no problems with signal interruption, Surapong Laoha-Unya, chief executive of BTSC, said the company will continue to work with AIS to conduct tests throughout the lines to boost confidence.
BTS uses the 2500MHz range on three slots for its electrical and signalling system, close to the 2500-2600MHz range won by AIS.