2m FM 12.5kHz Channels

Today I activated G/SP-008 Boulsworth Hill - Lad Law. I was called by Tom @M1EYP from G/SP-015 The Cloud on 2m FM. We were really struggling to find a clear frequency (who says 2m is dead?) so I suggested 145.5125 since the “half” channels don’t seem to be used much. But Tom said that if he transmitted on that frequency people in his area would complain he was interfering with the calling channel on 145.500 (S20/V40). I thought 12.5kHz channels had been the standard for 30 years and all modern equipment handle these fine. Or are there still lots of people using old equipment? What is everyone’s experience of this?


Andy is correct,
On the 2m FM band there are lots of people using 25kHz channel spacing equipment or have equipment that has poor rejection 12.5kHz away. It is also good practice to leave a “guard” each side of the calling frequency. You are much more likely to find an empty channel on say 145.4625 or 145.3125.

Most people never use the half-channels

If stuck for a channel don’t forget the 144.500-144.794 band plan is “all modes” and therefore also good for FM


Most radios let you do either 12.5 or 25 kHz, they just come set to 25 kHz as default and people don’t change it.
I had the usual one where someone running QRO changed to the frequency I was on so I couldn’t hear any chasers.

Half channels are often used on the FMAC night because there’s limited space for the contest, but you get people leaving their radio set for 25 kHz and taking up 3 of the half channels.
I was going go down to 144.600 MHz today but didn’t get any more replies to my CQ.