How to execute a script before use a dvb card

Hi Together,

Is it possible to execute a script before tvheadend start a recording or is used for a live tv stream?

I have one DVB-S and one DVB-T card.
A few Channels can i only recieve with DVB-T. But to get a good DVB-T signal I need an active DVB-T Antenna. And i like to switch on the active Antenna only if i view a DVB-T channel.