When I did a manual retune, which worked well I noticed some channel numbers on the post code checker site against the Rosemarkie transmitter had a + or a – against them. These were not listed on my box, just curious
Which unit are you refering to, so we can move this to correct forum
+/- next to a channel number means that the centre frequency of that channel is offset by approx 167Khz to improve coverage and/or reduce interference between transmitters.