So the terrestrial and satellites are two completely different parts on ur box. For the satellite I would imagine that for the likes of channel 5 that the frequency may have changed but I actually don't recall them channels changing frequency. All you have to do is retune the satellite part to get back ur channels. Also u could have problems with ur satellite dish. If the lnb starts to give trouble which is unusual with newer lnbs some of the channels drop out. Also ur dish could have moved either because of wind of rust which causes channels to drop out. Trees can also affect signal but usually not this time off year as the leafs are falling off. The terrestrial then works of an aerial and its sounds likes like some thing from the box to ur aerial. U shouldn't have to retune the terrestrial as the frequency wouldn't have changed. Could be an connection fault. If ur stuck pm me ur number I instal TVs I can call u back and may be able to explain it better.