It was all just too easy ...
I can't use MQTTLens (has something to do with a Google rash 
) so I tried MyMQTT on my Android phone.
I connect to the MQTT broker croft.thethings.girovito.nl with the same username and password as I use with ttnctl but I keep getting a message that I cannot connect to the broker.
Now I see in this thread tcp://staging.thethingsnetwork.org being mentioned.
Also, there seem to be 2 different Wikis: the one that can be reached from the thethingsnetwork.org page differs from the one in the forum. The first one has no "search" option in the menu.
It's all becoming a bit too much of a hassle for newcomers to find what we need.
As a developer of devices I just want a working network with a set of working tools. I like the initiative of thethingsnetwork and I already bought hardware for a gateway to get some coverage in Nijmegen but with KPN invading my region I'm almost at the point of collaborating with the enemy 
Can someone please prevent me from doing this!!!