Damn, you've embarrassed me now!. This thread made me think, I just dug out my Fox branded plastic whistle bought 25 years ago, unused and still in its tiny plastic bag in my oddments kit, and oh my god, it's disgusting
. It appears to have grown a sticky coating of... something, a veritable health hazard in fact.
In the bin it goes, I think I'll buy a cheap Eurohike one in town, that should be enough.
A couple of my packs do have a sternum strap whistle and they're pretty feeble, despite sounding very loud indoors.
... but how often can you be 100% guaranteed a signal in our hills and so would have to rely on good old fashioned signalling devices?
I can often walk for hours without a signal. On solo backpacks I always check-in to home a few times a day when possible, but e.g. on my Cateran Trail backpack I had no signal at all until around 6pm on one day.
Edit: typo only.