GPS

I fitted a GPS antenna to the cable entry box for my radio kit.  Not because I don't know where the box is, but rather because GPS can provide some very accurate timing information for Weak Signal PRopagation (WSPR) transmissions.  My Christmas present to myself was a Zachtek WSPR transmitter beacon and it needs a GPS input to work.

I ran my beacon for a bit this afternoon and was received from the far side of the US and Canada right down to Australia and up to the Arctic Circle in Norway (as well as right across Europe, Iceland & Canary Islands).  

It's an interesting tool to explore how antenna characteristics, atmospheric conditions, sunspot activity and time of day (and year) affect radio signals.