I am able to use MagicSDR on my Android phone to control my remote HL2's over the internet. I am using basic NAT/port forwarding to make this work (the same as you would need to make Thetis or SDR Console work remotely).
It's working very well and I see that "TX" is on the roadmap. I thought I would share this as I have had a number of people ask me about "mobile" HL2 operation.