If the box was working on 28.2,then you put a channel list for 19.2 east on it and used a FTA channel to turn your dish too you would be watching 19.2 east now.You don't need the signal finder till you get the FTA channel showing.
Sorry but I didn’t know the signal finder was only for the fine tuning
However, trying to use it made me realise that the receiver isn’t outputting the right voltage, although people don’t seem to have a clear understanding on how this should work