Hi,
I absolutely agree that the ttnmapper Android app together with a simple node that transmits periodically (no matter what the content is) is a great and easy way to map coverage. If you happen to have a GPS based node you might also consider mentioning your node ID and output format to @pade so the sample will also show up on pade.nl/lora.
Regarding Eindhoven: in exactly the same boat 
The Fontys gateway was accepting packets last week but it was not yet at its final destination as shown on the map. If you have a look at the ttnmapper.org site you see that the strongest samples (red) are not near the location where the gateway is placed on the map. I happen to know they are currently installing the gateway and it is probably down right now.
The samples on ttnmapper.org may show up with some delay. As mentioned by @jpmeijers "Once a day I aggregate and plot the data to a KML file." So maybe the samples will show up today.
If you live or work near Eindhoven you might want to visit the Madspace Meetups in Eindhoven, they are organized each Wednesday evening and Saturday afternoon, there are quite some LoRaWAN enthousiasts over there.
Thursday I drove on the A27 and got great coverage by the gateway on the Hogeschool Utrecht building. I also did drive on the A2 once and did not get that good coverage. See also pade.nl/lora
