View Single Post
Old 4-Jan-2010, 8:32 AM   #2
Join Date: Dec 2009
Posts: 632
Hello and welcome!

Originally Posted by cosmosmariner View Post
We have 3 HD TVs. Currently get DirecTV but are considering dropping that and putting up outdoor HDTV antenna. It seems we can mostly get UHF but still have a few important channels which are low band, I think(?).
Yes, you have one channel in low VHF (WTVF, channel 5, CBS). You also have two channels in high VHF (WNTP, channel 8, PBS, and WSMV, channel 10, NBC). The rest of your stations are in UHF.

There are several common antenna types available:
  • low-VHF only (ch 2-6)
  • high-VHF only (ch 7-13)
  • UHF only (ch 14-69)
  • VHF/UHF combo (ch 2-69)
  • high-VHF/UHF combo (ch 7-69)

Since you have channels 5, 8, 10, and several UHF channels to deal with, the easiest antenna type for you is a VHF/UHF combo like the Winegard HD7080P, Winegard HD7015, Channel Master 3018, or Antennacraft HD850.

Most of the major channels come from two main transmitter clusters. One group is at a compass heading of 59 degrees, and the other group is at a compass heading of 29 degrees. These groups are close enough to each other that you should be able to get all of the channels by pointing your antenna in between these two clusters. That would be about a 44 degree compass heading.

Since you need to split the signal three ways, this is going to result in decreased signal strength going to each of your TVs. Because of this, I would also recommend adding a mast-mounted pre-amp like the Channel Master 7777 or Antennacraft 10G202. This will boost the signal enough to overcome the signal loss caused by the cable and splitters.

I am on a high ridge and would like to mount the antenna on my house side or roof. Cable length could be up to 70' for the farthest TV from antenna.
The long cable run is another good reason to include a pre-amp in the setup. Once you include a pre-amp, the length of the cable becomes almost irrelevant.

All of your signals are showing "1Edge" in your tvfool report. This means that almost all of your signals are partially blocked by a hill and must diffract (bend) over the top to reach you. It looks like there's a hill about a quarter to half mile away from you that is causing this. Note: Line-of-sight visibility to the transmitters is not required for great TV reception. It's just good

Your tvfool report was done with a 10 foot antenna height. You might want to experiment with different heights to see if increasing the height has any impact on your signal strengths. The easiest way to experiment is to use the Online TV Maps tool. This tool lets you edit the antenna height interactively, and you can watch your signal strengths go up or down (look for changes in the "NM" values).

Just speculating, I'd guess that a little bit of added height (like a rooftop mount at around 30 feet) will probably improve signal strengths quite a bit. This can happen if you are "just inside the shadow" of a nearby hill (less than a mile away), and adding a little height puts you that much closer to the line-of-sight signal.

Depending on your mounting preference, some good roof-level mounting options would be:
  • Chimney straps - Avoids putting holes in anything if you have a suitable chimney.
  • Eave/wall mount - Mounts at the side of the house (less likely to cause leaks because it is not going through the roof).
  • Tripod - The feet are mounted right on the roof. It is very sturdy, but may have some risk of causing leaks.
To avoid having the roof itself influence the performance of the antenna, it's best to keep it at least ~4-5 feet above the roof. Antenna masts of 5 and 10 foot lengths are readily available and should work out nicely.
mtownsend is offline   Reply With Quote