For speedfreaks that already own a Android phone a good alternative could be a Mobile App. Currently there are two Apps available for use on our platform.
Both Apps produces doppler speeds, at the same quality level of the old GT-11 .The Apps records Dopplerspeeds from the GPS-chipsets that are implemented in all recent smartphones, so the accuracy is comparable to a GT11, the only missing item is the Dopplerspeed-error (SDOP) that only the GT31/GW52 or ublox-based units (Thingee) support.
So for record purposes it is not suited, however, for fun rankings it is way better than e.g. positional data from standard units. The SBP/SBN-files can be posted directly from the smartphone to GP3S or processed by GPSResults.
Please keep in mind that very cheap cellphones < 100€ will not perform very well since they use cheap GPS-chipsets and antenna - the reason for outliers etc has nothing to do with the App that just uses the data from these chipsets!
Of course an Aquapac is required and pressure on the touchscreen has to be avoided in order to not start other activities on the phone! Energy saving options on the phone should be disabled.
Download it at https://play.google.com/store/apps/details?id=com.windrace.pro&feature=search_result . or a free version (with ads) at https://play.google.com/store/apps/details?id=com.windrace&feature=search_result WindRace.pro is an Android app for windsurfing, kitesurfing, yachting and other sailing sports. The app does not requires an internet connection.
Download it at https://play.google.com/store/apps/details?id=com.mfuchs.gpslogit , this App is available at Google Play Store and developed by Manfred Fuchs, and is a good alternative for first-time and fun-speedsurfers.
After download to your Android cellphone (Android >= 4.4 required, minimum screen resolution 480x800)there will be a warning since the app does not come from Google Play and you have to allow installation from unknown sources once: