it only 'drops' the signal when you change the MAIN receiver to a channel that the Secondary receiver was not programmed for.
For example: if your Main receiver was on channel 112 HGTV on Satellite 129 when you then programmed the Secondary receiver, the secondary receiver is then ONLY going to see ANY channels on satellite 129. If you change the MAIN receiver to a channel that resides on satellite 110 or 119, you will LOSE the satellite signal on the Secondary receiver/tv.
In essence, if you want to watch channels on the Secondary receiver/tv, you have to KEEP the Main receiver on the same satellite. The antenna only has one 'eyeball', and it can't therefore 'see' two different satellites at the same time. The Main receiver has priority.