Originally Posted by Awesomeness
Is it possible to get HD stations from cities 100 or 200 miles away? Is it possible to get this signal to lock consistantly. For example, for the people living in the Chicago area, is it possible to lock a HD signal from Milwuakee (90 miles away) or Indy (180 miles away)? In addition to the Bears, Cubs, Sox, and Bulls, this would give Chicago the Bucks, Packers, Colts, Brewers, and Pacers games.
I am willing to buy 2 additional antennas and point them in the correct directions. My questions are, how high would these antennas need to be? Is there any correlation betwen height of the antenna and the distance of the signal recieved?
What is the farthest a HD signal can travel and lock consistantly assuming the antenna is big enough and high enough?
Generally, yes, the higher the antenna (on either end) the better the range..
BUT there are a lot of variables....how tall is the transmit antenna? How much ERP (Effective Radiated Power) are they running? There are a couple of math issues that come into play:
Transmit signal in dbm (transmitter power minus cable loss times antenna gain)
Transmit path length (visual or radio horizon)
Path Loss (varies per freq..the higher you go, the more you loose)
Receive antenna gain
Receive antenna height
Curvature of the earth (the K constant)
If the station is using a 2000ft tower, the "visual" horizon is ~Square root of 2 times the height....so 2000x2=4000 Take Sq Rt and you get ~60+ miles. RF or radio horizon is about 1.2-1.4 that (depending on terrain between the tower and viewing antenna/TV...
Add the rcvr antenna range in (say for 30ft high) and you get 70-80miles top reliably. AND this also depends on the power the station is transmitting at and how low a signal you receiver can decode...(which in the DTV realm) you can also cause it not to decode IF it gets overloaded..which is something you may not be able to tell unless you have a special piece of gear called a spectum analyzer...
Hi power CB ops or commerical two way radio ops near your location can cause the DTV tuner to overload...and goodbye signal! People living in Chicago watching out of town signals?? Doubtful...the local signals will likely cause overload or desense of the amp / receiver...Especially with the TV stations being downtown with the antennas..Houston on the other hand, has 2000ft towers SW of town...people on the east, north and northwest side has better chance of distance over those on the south or SW side where the towers/antennas are.