[mtownsend]

Originally Posted by Michael-60

another question is what height should the antenna be at. My roof peak is 15feet above ground with a location of maybe 50 feet to TV. The other location is my chimney at 80 feet.

If you have an existing mast or mount that is still in good shape, then you can just use it. If you are installing a new antenna mount, then choose whatever you feel most comfortable with. There are many mounting options available depending on the kind of roof you have and whether you have a chimney or not.

I usually consider the following:

1) Chimney Mount - Uses stainless steel straps to wrap around an existing chimney, and has a bracket designed to hold a vertical mast. It does not require any holes in the chimney nor the roof.

2) Eave Mount - Attaches at the side of a house at the apex of an A-frame roof. Holds a vertical mast that can extend above the roof level. Holes go into the side of the house instead of the roof for reduced chance of leaks.

3) Wall Mount - Attaches at the side of the house on the wall. Holds a vertical mast that can extend above the roof level. Works with flat roofs as well as pitched roofs. Holes go into the side of the house instead of the roof for reduced chance of leaks.

4) Tripod - Three feet attach directly into the roof. Bolts go into the joists that support the roof. Gives greater flexibility in choosing a location for the antenna and is very sturdy. Holes go directly through roofing material, so may not be suitable for some roofs, and may increase the risk of leaks in others.

Also my coax is 20 years old.

You can inspect it for any wear and tear, especially on any outdoor exposed sections or areas when there may be bends/kinks/cuts. At the very least, you might consider replacing the connectors on the ends if they are showing any signs of being loose or having corrosion.

If it's not too much trouble, it's probably better to replace the coax now just so that you don't have to worry about it for the next 20 years. RG6 is the preferred cable type since it is relatively inexpensive, shielded, durable, and relatively low loss. RG6Q (quad shield) is a little better, but is not required (will not make any difference in most situations).

I see on the chart after the station name is a DT, which I assume means Digital TV?

The -TV and -DT suffixes do not actually mean anything. These are simply the call letters that the FCC uses to track these records in their database. The actual channel type is stored separately in the database. Ever since June 12, 2009, the majority of US transmitters have switched to digital operation only. A few low power translator and booster stations still operate with analog signals, but you usually don't see very many of them any more.

In the tvfool reports, the digital stations are printed using "blue" text while analog stations are printed using "purple" text. Most of us will pretty much only see digital stations from now on.

One confusing item is that KTVU has two listings at 48 (FOX) and 44(2) with a 77 degree spread. We watch 'American Idol' and '24' on our Channel 2 (KTVU-FOX) in Livermore. How can I tell which one it is?

Fox has been granted a construction permit for a secondary transmitter in the south bay for "fill-in" coverage. They are trying to improve coverage in areas where their Sutro transmitter doesn't reach. For now, only their channel 44 transmitter is active.

Their channel 48 construction permit was granted by the FCC on June 30, 2009. I'm not sure when the new transmitter is planning to go on the air. When it does go live, you will be able to use either signal to get KTVU. The channel 48 broadcast may end up being stronger for you because it comes from Monument Peak.

Both broadcasts will automatically map themselves to channel 2.x through the magic of "virtual channel mapping". Regardless of what frequency the signal is broadcast on, the data in the channel tells the TV what channel number to display on the screen.

If you ever want to check the real broadcast channel of any station, most TVs have the ability to tell you which one it is. You'll just have to figure out how to get your TV to show the RF channel number through the menu or info screens.