Alarm, Wireless V wired

If you can, get one on 868MHz. It won't give (or suffer from) interference anywhere near as much as the other frequencies. The newer models of alarms tend to use this frequency. 434MHz in particular is very busy. Unfortunately the cheapest wireless alarms are on 434MHz - of course!

Out of interest is it possible to reduce the volume on the external alarm, probably be a Yale wireless.

Something to be said for fitting the sounder box out of easy reach.

regards

Most sounders and now sealed so you need a cordless drill to get the foam in.

At which point you might as well just use a hole cutter at the correct point and then cut the sounders wires.

Q) Is 20' above the ground in the middle of a bare gable end wall "out of easy reach"?

A) No, that's where the sounder for the local Co-op is but it didn't stop it getting filled with foam a few years back. Open area/car park on Front Street in plain view with commercial/residential properties all round.

Well out of my reach, anyway:-)

Transit tipper with an upturned broom and a set of extending ladders?

I had a closer look at one of my spare boxes today. It appears to have a festoon halogen and possibly an led potted in plastic. I will attack it with the multimeter and try to establish if there is already a resistor in series.

regards