In 2014 the size of the TV spectrum was reduced to provide more space for expanding mobile phone, Internet and NBN services, particularly 4G. This is why most of regional Australia had to re-tune their TV's (in 2104). The redevelopment of the spectrum is referred to as LTE (Long Term Evolution).
Of course, most antennas, signal amplifiers, TV's and PVR's still receive this part of the spectrum and, now that the 4G Service Providers are using these frequencies, we are finding many problems. Mainly, it's in places close to phone towers where the LTE signal is very strong which causes overloading (too much signal in aggregate).
Fortunately, the solution is simple: installation of an LTE filter which cuts out these unwanted frequencies. These cost about $110.00 (parts and labour), depending on your location.
Also, many new signal amplifiers have in-built LTE filters. If you have an amplifier and it's getting on in age, it may be more economical to replace this (costing $159.50, parts and labour).
If your antenna/amplifier is less than 12 months old, say installed after 2014, it may have an in-built filter that can be easily set.
Contact MAS for further advice or assistance.