This predicted coverage map shows generally where the WLT translator signal will be usable. The red circle is centered on Parachute Hill where our communications tower is located.
Note that this is “predicted” coverage, not “measured” It is calculated mathematically using data about the antenna design, antenna height, transmitter output power, and topographic features from 2 to 10 miles away from the transmitter location.
Because the calculations don’t take into account terrestrial obstructions beyond 10 miles from the transmitter, they don’t recognize distant obstacles, such as, for example, Cape Perpetua being a small impediment to our signals getting into Yachats. Even nearby locations can be much different from the predicted coverage. The coverage map clearly indicates that our transmitters should reach Mapleton, 13 miles inland from Florence, but because of shielding terrain, there is no signal there. Two of the Eugene TV stations operate separate translator facilities to provide service to that community.
On the other hand, the signal strength out to sea is probably understated. Without hills and trees, it’s likely possible to receive a great picture all the way to the horizon and a bit beyond.
Locations such as Siltcoos Lake, and other hilly environs will experience hit-or-miss propagation, depending on which side of a hill you might be on, and the elevation of your site.
It is possible to run complex computer simulations that take into account more accurate terrain modeling, but it is very expensive, and is usually only put to task in high-stakes radio frequency installations. For now, all we have access to is the FCC contour maps, which is the only data which the Commission regards as valid.
The tools on TV Fool may be useful for getting information specific to your exact location.