After 5 years on my chimney, it looks like my Watson W300 has had it. It had been used a bit before that as well, as I'd had it since 2000.
Recently I'd been noticing that received signals would be lower than normal until I transmitted, and then they would go back up, but when checking the SWR everything was OK. I thought this might have been a bad connection in the coax plug indoors, but after changing the plug it did exactly the same thing.
Then yesterday, which was very windy, the SWR was actually changing on transmit (between 1.3:1 and 4:1), and the received signals were varying without me doing anything.
It might just be the plug at the antenna but as the pole isn't moving it seems more likely to be the antenna. Either way it needs some work doing on the chimney. I think I'll go for a new tri-bander, I've got a 50MHz half wave vertical in the loft but it picks up a lot of noise.