Lectrosonics VP300W User Manual download pdf (Page 7)

Portable Public Address System

4.01.2 Determining the absolute optimum location for the FM-AV5 and M30 transmitter is a matter of trial and error.

However, by observing a few simple rules, satisfactory system performance can be obtained with a minimum of effort.

(a) Locate the FM-AV5 at least six feet away from walls and large metal objects such as blinds and heating/air

conditioning ducts.

(b) Locate the FM-AV5 at least four feet above the floor and at a point where the transmitter is in sight.

(d) If practical, locate the FM-AV5 away from roads carrying motor vehicles.

(e) Locate the FM-AV5 away from dead spots. These can be found by experimentation as discussed in paragraph

4.02.

(f) Locate speakers so that the emitted sound cannot readily enter the microphone.

4.01.3 "Feedback" is an undesirable howling or squealing sound which must be avoided. Two interacting factors

cause feedback. These are:

(a) The amount of system sound output coupled back into the amplifier system via the microphone and receiver.

(b) The gain setting of the R300 module VOLUME control.

Feedback can be prevented by ensuring adequate separation between the microphone and the sound system speak-

ers. If gain is increased the separation must be increased. Holding the microphone closer to the mouth will allow the

gain to be decreased and thereby reduce the probability of feedback.

4.02 DEAD SPOTS

4.02.1 "Dead spots" are locations where reception of the transmitted radio waves is poor. The two main reasons for

dead spots are:

(a) An object between the transmitter and receiver is either absorbing or reflecting the transmitted radio waves so

that they cannot reach the antenna of the receiver.

(b) Refelective surfaces between the transmitter and receiver cause the radio waves to arrive at the receiving

antenna by multiple paths. This can result in poor reception and sometimes, no reception at all.

4.02.2 Finding dead spots is simply a matter of experimenting with the location of the FM-AV5 relative to the location

of the transmitter. If the transmitter location is stationary, the FM-AV5 is moved around until the area of best reception

is found.

4.02.3 If the person using the transmitter is going to be moving around, he should determine by actual experimenta-

tion, any dead spots that exist in the area he plans to cover. Once they are located, they can be avoided during the

actual presentation.

NOTE

USE OF MICROPHONES OTHER THAN LECTROSONICS M116, M118

AND M131SW MAY RESULT IN INFERIOR SYSTEM PERFORMANCE.

5. M30 SERIES TRANSMITTER OPERATION

5.01 GENERAL

5.01.1 It is characteristic of FM receivers that they can receive a transmission from only one transmitter at a time.

Simultaneous use of more than one M30 transmitter with a single receiver will result in a loud squeal. If the individuals

using the microphones could be disciplined to turn one transmitter off before another is turned on, it would be possible

to use multiple transmitters on the same frequency, however, this practice is not recommended.

Rio Rancho, NM – USA

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Lectrosonics VP300W User Manual Page 7