[bobsgarage]

In theory, it is possible to add its SD analog output from one antenna system to your other system on channel 3 or 4 with the modulator in the 7003.

I'm not sure I follow that, sorry. I mean the part of how I get two antenna systems to work on it. Or do you mean combine two STBs?

It is also possible to add its HD output to the other system with a modulator on an unused UHF channel. I haven't done either.

I went to that link, and tried to keep up, but I don't even know what a modulator is. Those guys were talking about stuff I never heard of