Signal loss for the cable (not sure if it is this exact type, diameter is a close match though (1.13mm). The loss of that is 3.73 dB/meter of cable (at 3 Ghz), so the difference from the "standard" antenna of approx 10 cm length (excluding the "antenna" itself) to a 400 mm long one (40 cm) is:
Extra length is 30 cm. So the extra loss due to the longer antenna is around 1.2 dB. This is insignificant in most of our cases. The change in signal strength will be many dB just moving the plane a little (easily in the order of 10 to 15 dB) and certainly MUCH less than the penalty of bringing the antenna inside the fuse
UFL/cable data:
http://www.mouser.com/ds/2/185/U.FL_catalog-939761.pdf