Can you describe your situation in more detail?
What are the antenna model #'s?
What channels are you attempting to receive?
Please post a link to a TV Fool report for the antenna location and elevation.
Combining a single UHF antenna with a single VHF antenna is easy and reliable. Simply use a UVSJ or a preamplifier with separate inputs for UHF and VHF.
Examples:
http://www.solidsignal.com/pview.asp...Combiners&sku= and
http://www.solidsignal.com/pview.asp...ku=02057207774
The reason that there is little trouble with this scenario is that there is a relatively large difference in the frequencies between the two bands, making it easy to manufacture filters that can isolate the two antennas, preventing one from interfering with the other.
Combining signals from two antennas in the same band is possible, but things start to get complicated as the difference in frequencies is so much less. Here is a consumer grade product that can be used to insert one channel from one antenna, into a group of channels from another antenna.
http://www.warrenelectronics.com/Ant...Jointennas.htm As you read the product description, you will see that there are caveats and restrictions regarding adjacent channels.
If cost is no object, here is a commercial CATV head-end product:
http://www.techtoolsupply.com/Produc...Code=HPH-860AD At about $750 per channel you get the ability to move a channel from it's over-the-air frequency, to any CATV system frequency you choose. Buy one for each channel you want on you own private CATV system and viola'! you're your own cable TV mogul.
Some folks are happy with an A/B switch, plus the extra coax involved with running a feed from antenna 'A' and a feed from antenna 'B' to each set.
Finally, with computers getting incredibly cheap (relative to their computing power and speed), many folks are turning to home theater PC products...
http://forum.tvfool.com/showthread.php?t=820
