6
Case III: (continued)
Small Auditorium or Church
Factor
2 Antennas On Back Wall
Equal
Distance
All of the transmitters are about the same distance to the closest antenna. If there is IMD interference it will be small
compared to the transmitter’s signal. This meets the design rule.
Diversity
The antennas are separated so at least one antenna is always out of the transmitter antenna’s null. There is also antenna
redundancy and better transmitter coverage due to having two receiver antennas. This meets the design rule.
Line of Sight
The antennas are placed over the audience to keep the line of sight for both antennas. This meets the design rule.
Cable Loss
Short antenna lengths reduce loss and cost. Use low loss cable to assure total loss in each run is less than 15 dB.
Range Loss
All transmitters are far from the antennas, but within range. It meets the design rule.
Transmitter
Power
Use 25 mW to overcome range loss.
Rating
Expect excellent performance with small and large channel counts.
Factor
2 Antennas On Side Wall (or Rack Mounted w/ Dipoles)
Equal
Distance
The RF Signal of transmitters close to the receiver antennas can lower the sensitivity of the receiver so that transmit-
ters that are farther away do not have an adequate signal level at the receiver. Also using transmitters too close to the
receiver antennas or at too high of transmit power can cause Intermodulation Distortion which can either shadow desired
transmitter signals, or cause distortion in the receiver. . Expect dropouts and hits with large numbers of transmitters.
Diversity
Diversity is defeated when the antennas are too close together. Expect dropouts when the transmitter antenna null points
at the antennas.
Line of Sight
All transmitters are in the line of sight of both antennas but because the antennas are mounted too low they can easily be
blocked by people or white-boards, etc.
Cable Loss
Use low-loss cable to assure total loss in each run is less than 15 dB.
Range Loss
There is too great of distance between the transmitters that are closest to the receiver antennas and those that are farther
away for reliable reception of all transmitters..
Transmitter
Power
Use 10 - 25 mW output power to assure pick-up of the far transmitters.
Rating
This system is prone to dropouts and hits with large numbers of transmitters.
3rd Choice
D.
Not Recommended
C.
