I use an 18 month old(ish) Garmin 1030+ to record rides and, sometimes to navigate for me.
I also have 2 heart rate straps; an "expensive" Garmin unit (I think it came with the 1030+ as part of a package) and a cheap Halfords unit that was an "emergency" purchase when I'd failed to pack the Garmin strap before a tour.
Initially the Halfords unit seemed to perform better but, after a period of time, it started to develop a mind of its own. What happens is that, from time to time, it starts to increase the HR one beat at a time until it reads up to 240 bpm (the most that the 1030+ will record ?). I've seen it do this in the pub or when riding slowly; HR rises from 72 (seems to be a default value on the 1030+) or whatever value to very high bpm over a period of several minutes and by one beat at a time. When I've seen this happening, clicking the sensor off one of the electrodes on the strap stops it at 72bpm according to the head unit. It then stays at 72 for 5+ minutes before, usually, going "blank".
On the other hand, the Garmin strap either doesn't start recording immediately or, if it does (72bpm....) it stops soon after I start riding. It does, sometimes, start again either randomly showing around 72bpm or, seemingly, recording my HR accurately. Then it stops again randomly.
I always moisten the strap before I put it on to ensure good "conductivity". I've also just put a new battery in the Garmin strap and I've recently "tightened" it (it was a bit slack). None of these actions seem to have improved the performance/accuracy/reliability of the straps.
Any thoughts please ?
I'm aware that the 1030+ is the common denominator but I find it hard to imagine that it's at fault since it picks up the strap signals.
I'm also reluctant to buy another HR strap purely "on spec" to try a further experiment although I will do so if that's what the majority verdict is. Cheap Halford's, expensive Garmin or other makes ?
FWIW, my resting HR (measured in the morning in bed against my watch) is 45-50 and sitting at my desk it is 60-65 bpm. I've rarely seen 150bpm+ on the bike. If I do, it's an extreme effort that I can't sustain for very long. Usually 140-150bpm is a hard effort.