AJM wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div class="Wj3C7c">><br>> Do they make a product that will combine my HD over the air with my
<br>> cable from the cable company so that I can combine them on one coax<br>> and then feed it into my TV?<br>><br><br></div></div></blockquote></div>Notwithstanding the interference that would occur between the cable and the broadcast TV signals, there are other technical reasons not to attempt to combine the cable and antenna signals. Some of the frequencies used by cable are in the gaps between the VHF LO (54..88 MHz, broadcast channels 2..6); VHF HI (174..216 MHz, broadcast channels 7..13; and UHF (470..800 MHz, broadcast channels 14..69). The cable companies are required to keep the signal from radiating, to avoid interfering with over-the-air users of these frequencies. Users include paging transmitters, police, fire, and other government services, other two-way land and marine mobile services, and also civilian and military air traffic control.
<br><br> A T or passive splitter-used-as-a-combiner will not have nearly enough isolation between the cable and the antenna, and would put the cable company in violation of FCC regulations. If you were found to have caused the violation, they would have grounds to seek reimbursement for any fines, which can reach $10 000 per day. And in these litigious times I wouldn't want to be the guy who was found to have caused Flight XXX to crash because an air traffic controller's directive was wiped out by a cable TV signal radiated by your antenna.
<br><br>In short, don't do it. <br><br>You might be able to find a coaxial relay or switch which has the required isolation, and rig up a way to control it with a parallel printer port output bit from your Myth frontend. Maybe an LNB switch from the satellite TV world would have the required (60dB?) isolation. Or maybe you could use the coaxial relay from an old Nintendo or other video game.
<br><br>Regards,<br>Bob Koblish<br>