Tests are taken from a roof top in Burbank, California.
When the tests were conducted, they are done very quickly. There is a receiving
receptacle above the rotator that allows switching antennas with no tools.
This is very important as reception/weather conditions can change quickly.
Local stations are picked up from Mount Wilson, about 15 miles away at 3200'-3600' elevation.
Attempting to pickup stations from Mt. Wilson can be a good test for multi-path
interference from this location. About 5 miles away is a large mountain peak
that rises about 1000' above my line of sight with the transmitters. Signals
must travel either over or around this peak. My receiver must differentiate
between the good signals and the bad. The direction of my antenna indicates that
strongest signals are traveling directly over the peak. The signal either bends
over the mountain (knife edge effect) or reflects off the atmosphere to reach my
antenna. For this condition, a medium gain antenna with good multi-path
rejection (high F/B ratio) performs best.
Long distance stations are picked up from San Diego, about 130 miles away at
a 700'-1800' elevation. There are no significant mountain peaks in my line of
sight. Due to the distance, the line of sight is actually being blocked by the
curvature of the earth. San Diego is a coastal town, most of the path the signal
travels is along the coastline. Because of this, weather becomes a critical
factor in signal reception. In favorable weather conditions, signal levels can
be very high with the help of
tropospheric ducting. In bad weather conditions, the moisture and fog in the
air can create a wall of water. The lack of the ducting causes the signal to
completely disappear. A high gain antenna is required to pick up these distant
stations, but you will still need favorable weather conditions to get reliable
|Set Top Box -Tuner
||RG-11, 50' antenna to receiver
|Antenna Height above ground
||30' = 17' house + 13' mast
||1.375" diameter, telescopic 30-48", 3" increments
||(2) 1.250" diameter x 4-1/2' length, tempered steel,