For those of you with antique GPS watches like me (Garmin 310XT), you may be interested to know you can sync via (some) Android phones via ANT+ just like those fancy futuristic folks with Bluetooth / WiFi etc !!
I have a Galaxy S5 and it supports the ANT+ protocol so I can now sync via the 'Garmin ANT+ Watch Uploader PRO' app without having to get home, start computer etc etc. Such a revelation, have been mucking about with the USB dongle and PC for years !!
List of phones that have ANT+ here:
www.thisisant.com/directory/filter/~/60/~/
List of supported devices by the app I use here:
play.google.com/store/apps/details?id=co...ty.ant2net_pro&hl=en 
