RF signal combining possible?

I work in an environment, structural steel with EM interference, that does not permit AM or weatherband signals to reach my receiver. I have access to the roof (50 ft in height) on which I currently have an outdoor over-the-air flat antenna for receiving TV and FM broadcasts using a Rg6 coax to my TV. If I install an AM antenna there as well, can I use the same Rg6 coax for both antennas without degradation of signal? If so, I assume I'll need a couple pieces of hardware to make it work, such as a signal combiner and splitter, which I expect to have some loss. I have an antenna picked out, but not yet bought, that has a Rg-62 cable with a Motorola connector on it. I was planning on cutting that off and crimping on a standard coax connector. Thanks for reading.

The thing you need is a diplexer or triplexer at each end. Labgear seems to be the main manufacturer I see.

You will need to make sure you get the right one for the bands used in your country.