[hvalentim]

Interesting test!

How many walls between outside and the RX unit?
Is the RX unit at ground level?

Direct line of sight (see attached pic.) should include three to five walls and a number of trees. RX unit placed at ground level, in a desk, yes.

Once I have the TX up in the roof I will do another round. This time with the RX in the vehicle.

---

try with RG-58, although you will probably find it harder to work (more thicker than RG-174)

That was the main reason why I chose RG-174. It is lighter, easier to bend and thus less prone to force/break the solder while moving the unit during the installation.