Telstra Mobile Smart Antenna

[crosby6]

We have a Telstra Mobile Smart Antenna 850MHz Next G with a Yagi Next G Antenna mounted externally. This typically boosts signal from a 4G tower 20kms away into our home for an iPhone4 (3G capable) and iPhone6 (4G capable). Lately whenever we try to receive or make a call with the  iPhone4 (3G) we lose all boost from our Smart Antenna with a 1E error message meaning no signal on the window unit.  

When the booster is off we can raise a weak 1 bar 4G signal from high in the bathroom window and 2-3 bar 3G signal.

Any ideas on this frustrating problem would be greatly appreciated.

[Jupiter]

My first thought would be, has the antenna moved slightly. Yagi antennas need to be pointed at their target fairly accurately and a shift of a degree or 2 could greatly affect it. I would also be checking the cable connections at the antenna and the unit to see if there is anything loose or exposed. Water in an external connector could short out the cable and kill the signal.