My wife and I have used a wireless doorbell in fresh snow conditions 
when walking our guide dogs.  The doorbell goes on a window sill 
outside of the front door and the button in the pocket of the current 
dog walker.  Once the4 sidewalks have been cleared the house is a lot 
easier to find!
Pat, K9JAUAt 06:47 PM 4/8/2015, you wrote:
>This has precious little to do with ham radio but the blind mice mega mall
>is selling for about 25 dollars per unit, a weather proof wireless door
>bell.  We have a front door and a side door in need of some alert so I put
>the single battery, which was included, in the outdoor weather proof button,
>and 3 double A batteries, not included, inside the bell box which, they
>claim, will receive the door bell signal for 250 feet.  Boy, I hope my
>neighbor doesn't get on the same frequency because I saw no place to change
>channels.  Anyhow, for the price, I thought wireless hams would like to know
>that the wireless door bells work fine.
>
>Phil.
>K0NX