DAB+ in the Car: Adapters, Retrofits and What the Swiss Tests Found

New cars carry DAB+ built into the dashboard, according to dabplus.ch. Older ones, including many used cars that newcomers buy second-hand, may not. In those, the radio is FM only, and FM no longer carries the main Swiss public stations. They left FM at the end of 2024, as the FM switch-off page records.

How many cars are affected

TCS, the Swiss touring club, counted in November 2024 about 1.8 million passenger cars without DAB+, which it put at 38 percent of passenger cars. A car with a plain FM radio is not broken. It just no longer receives SRG stations.

The options, from simple to thorough

Konsumentenschutz sets out three routes. First, keep the FM radio. Second, play the radio through a smartphone over Bluetooth or USB. Third, add DAB+ with an adapter or replace the radio.

SRF describes how the adapter route works for older cars with an AUX input. The adapter picks up DAB+ with its own antenna, often fixed to the car with adhesive, and feeds the sound into the car through the AUX cable. At the other end of the range, a garage can install a DAB+ radio and an antenna properly.

What the tests found

TCS tested four simple DAB+ adapters and two FM transmitters and published the results on 26 November 2024. All four adapters received DAB+ well. Sound over an AUX cable was clearly better than over FM. FM transmitters turned out to be unstable: in two of four car radios the radio switched away from the transmitter after one to two minutes, and legal power limits apply. All four adapters had service following, which switches to another source for the same station when reception drops, and most offered Bluetooth hands-free calling.

Kassensturz tested twelve of the best-selling adapters a few weeks later, in December 2024, for cars and for stereos. Adapters for cars came out well. Those for stereo systems failed with the antennas supplied in the box. Antenna placement was decisive.

The test pages list the individual models and their scores.

Keeping the old FM radio

Konsumentenschutz lists keeping the FM radio as a legitimate option, and FM licences now run to 2034. The catch is the content: a plain FM set receives private stations that hold an FM licence, but not SRF, RTS or RSI at present. For drivers who mostly listen to SRG, that makes the option a poor fit until SRG is back on FM, and no start date for that is confirmed.

The smartphone route avoids hardware altogether. The phone plays the SRG stations over the internet and sends the sound to the car by Bluetooth or USB. It needs mobile coverage and uses mobile data, whereas DAB+ needs neither and is available in the national road tunnels.

Fitting an adapter

Three things decide how the result sounds. The car needs an AUX input, because the TCS finding on sound refers to that connection. The antenna needs a clear position, and reading the manual on that point is worth the two minutes. Without an AUX input, a garage fit or a new radio is the likelier route.

On coverage, dabplus.ch says DAB+ covers over 99 percent of the population, and the coverage page explains what that figure means. For indoor devices, see the DAB+ radio guide.

Imported and second-hand cars

A car imported from abroad may carry a radio built for another system, and the same goes for a second-hand purchase of unknown origin. The test is the same as at home: switch to the DAB+ source, run a station scan and look for Swiss stations. If the scan stays empty at a spot where coverage is known to be good, the radio probably cannot do DAB+. The checklist walks through the other causes.