Is it possible to use a longer coax cable as the supplied 15 mtr?

This is possible, it has been tested with a total coax length of 30 meters.

However, the following matters are important:

• The coax must be of good quality (no thin coax, otherwise too much voltage loss will occur)
• If you use an external external connection on your caravan, you must also include the internal coax cable in the caravan. If the internal coax in the caravan is of lesser quality (thin core), this is an additional loss.