The Navcard reader in Tranzit can be build underneath the Pylon in the cornfield between the Farm and the Powerplant. Four parts are required to build it, and they are all scattered through the entire map. Being limited to carry merely one part at a time, the player has to add a certain part under the Pylon every time a part has been picked up. The locations of the parts are the following:
1) The meteorite: In the hole in the wall at Bus Depot, next to Mystery Box spawn.
2) The wooden plank. This one can be found on two possible locations.
In the Tunnel between Bus Depot and Diner, next to the M16 wallbuy.
In the lava part of the Powerplant, on a platform beneath the workbench and Tombstone.
3) The radio. This one can be found on two possible locations as well.
In the garage by Diner (in the room with the car) on top of a shelf. It must be picked up while jumping.
Inside the Prototype (Nacht der Untoten), located in a cornfield between the Farm and the Powerplant.
4) The electric box. This one can be found on three different possible locations.
In Town between the dumpster and the Mystery Box spawn.
In the farmhouse, next to the fridge.
Next to the busdepot, behind the lavapool.
Now follow Richtofen or Maxis, the choice is yours (for the next steps, choose Maxis or Richtofen steps).