I finally got time to test the "Bluetooth GPS Output" app for Android phones.
Instead of having to purchase a dedicated BT GPS receiver (around 60 Euro from eBay), you can use your existing Android smartphone (provided it has a GPS receiver, of course)!
Head over to: https://play.google.com/store/apps/details?id=com.meowsbox.btgps
The app is free, but has a 10 minute time limit. This is enough to test the functionality and even for some single frequency signal power mapping.
The good news is, that the full license costs just 1€!
Here you see the app in action on my Samsung Galaxy Note 3:
My KUBO tablet (running Windows 10) connects without issue to this app, recognizing a regular BT GPS receiver. And my SMA Simple Spectrum Analyser software is happy with the NMEA data: