The Marin Emergency Radio Authority has approved its next-generation project, which aims to reduce coverage gaps and increase capacity for first-responder radios with eight new antenna sites and improvements to 10 others. MERA released a draft environmental impact report on the project this fall; after receiving just a few housekeeping comments, it adopted the report last month without major changes. “We felt pretty good after reading the comments that we had done a good job of laying things out,” said Dave Jeffries, a spokesman for the authority. Marin must switch to a higher frequency by 2023 to comply with a Federal Communications Commission order that will allow the government to sell the vacated airwaves to private companies. Motorola already secured the bid to supply Marin’s equipment and has begun selling dual-band radios to MERA that are compatible with both the current and next-generation systems. Once the current system is vacated, the second band on the radios will allow firefighters to switch to the frequency that Cal Fire and the United States Forest Service use. “There will be a little bit of a learning curve for how to switch between those two frequencies, but I don’t have much of a concern about teaching volunteers how to use the [new radios],” said Jim Fox, the chief of the Inverness Volunteer Fire Department. MERA will buy the first set of radios and distribute them to local agencies, which will be responsible for any replacements. The plan includes new towers at existing hilltop infrastructure in Tomales, at Walker Creek Ranch and in Muir Beach. Existing sites outside Bolinas, atop Mount Barnabe and on the Inverness Ridge will be upgraded. Yet even with the upgrades, a map provided by Motorola shows that large coverage gaps could persist in West Marin. Due to the low number of calls for service in those areas, building more towers to address the dead zones wasn’t financially practical, Mr. Jeffries said. First responders have practices in place to work around the zones, he said, such as stationing someone away in an area with coverage in order to relay information. Once the system is built, Motorola will test to make sure the map is accurate and that the audio quality meets its standards. The higher frequency does worse in rugged terrain, but Motorola has guaranteed the upgraded equipment would make up for the lost efficiency, Mr. Jeffries said. This spring, the MERA governing board will set a work schedule and request bids for construction. The estimated $40 million project is funded by a 2014 ballot measure that imposed a $29 per year tax on single-family homes for 20 years.