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7

UHF Belt-Pack Transmitter

Rio Rancho, NM – USA

OPERATING INSTRUCTIONS

1)

Install a fresh battery according to the instructions on the previous page.

2)

Insert the microphone plug into the input jack, aligning the pins; be sure that the connector locks in.

3)

Attach the antenna to the jack on the control panel of the unit.  Be sure it is screwed in securely.

3)

Turn the power switch to the “ON.”

4)

Position the microphone in the location you will use in actual operation.

5)

While speaking or singing at the same voice level that will be actually used, observe the AUDIO LEVEL LEDs.
Adjust the AUDIO LEVEL control knob until the LEDs begin to light.  Start at a low setting where neither LED
lights as you speak.  Gradually, turn the gain up until one LED lights, then the other.

The “-20” LED lights when the audio level is about 20dB below full modulation.  The “0dB” LED lights when the
limiter begins to operate.  There is over 30dB of limiting range without overload above the “0dB” LED, so it is
normal and desireable that the “0dB” LED light up 5% to 10% of the time during use.

6)

Once the gain has been adjusted, the transmitter audio can be turned on to make sound system level
adjustments.

OPERATING NOTES

The AUDIO LEVEL control knob should not be used to control the volume of your sound system or recorder levels.
This gain adjustment matches the transmitter gain with the user’s voice level and microphone positioning.

If the mic level is too high —  both LEDs will light frequently or stay lit.  This condition may reduce the dynamic range
of the audio signal.

If the mic level is too low —  neither LED will light, or the “-20” LED will light dimly.  This condition may cause hiss and
noise in the audio.

The first LED turns on 20dB below full deviation.  The limiting LED turns on at full deviation and indicates that the
input shunt compressor is operating.  The input limiter will handle peaks over 30dB above full modulation, regardless
of the gain control setting.  The limiter uses a true absolute value circuit to detect both positive and negative peaks.
The attack time is 5 milliseconds and the release time is 200 milliseconds.  Occasional limiting is desirable, indicating
that the gain is correctly set and the transmitter is fully modulated for optimum signal to noise ratio.

Different voices will usually require different settings of the AUDIO LEVEL control, so check this adjustment as each
new person uses the system.  If several different people will be using the transmitter and there is not time to make the
adjustment for each individual, adjust it for the loudest voice.

Summary of Contents for UM195B

Page 1: ...UM1 95B UHF BELT PACK TRANSMITTER LECTROSONICS INC Rio Rancho NM OPERATING INSTRUCTIONS and trouble shooting guide...

Page 2: ...the input connector to power electret mics with either positive or negative bias Level indicating LEDs are provided on the control panel to make level settings quick and accurate without having to vie...

Page 3: ...ndor are fast enough to keep high frequency transient distortion at a low level and the low frequency compandor uses slower time constants reducing low frequency distortion to well below that of a con...

Page 4: ...ng use the LED brightness will also decrease When the LED is barely visible there will still be 30 minutes or more operating time remaining Since the internal circuits are all tightly regulated and th...

Page 5: ...with the 3dB point adjustable from 35Hz to 150Hz The actual roll off frequency will vary somewhat according to the low frequency response of the mic capsule being used The low frequency roll off contr...

Page 6: ...rtment press outward on the cover door in the direction of the arrow as shown in the drawing Only firm sliding pressure is needed to open and close the battery door Swing the door open and take note o...

Page 7: ...G NOTES The AUDIO LEVEL control knob should not be used to control the volume of your sound system or recorder levels This gain adjustment matches the transmitter gain with the user s voice level and...

Page 8: ...ructions Caution Do not allow the shield wire to touch any metal part of the connector shell The shield wire is the antenna on VHF models and poor operating range will result Shield Wire Crimp Tabs Ru...

Page 9: ...them sensitive to RF which can cause problems with the microphone transmitter compatibility If the electret microphone is not designed properly for use with wireless transmitters it may be necessary t...

Page 10: ...The normal hookup for line level signals is Signal Hot to pin 5 Signal Gnd to pin 1 pin 4 jumped to pin 1 and pin 3 jumped to pin 1 This gives a 40dB attenuator that allows signal levels much higher t...

Page 11: ...F 1 Transmitter mic gain set too low 2 Defective microphone or cord NO SOUND OR LOW SOUND LEVEL RECEIVER MOD LEVEL LEDs ARE ON 1 Receiver output level set too low 2 Receiver output is disconnected cab...

Page 12: ...l LEDs indicate modulation level 20dB below limiting and at the onset of limiting Controls 2 position OFF ON slide switch Front panel knob adjusts audio gain Audio Input Jack Switchcraft 5 pin locking...

Page 13: ...ere is a charge for an exact quotation We will be happy to quote approximate charges by phone for out of warranty repairs RETURNING UNITS FOR REPAIR You will save yourself time and trouble if you will...

Page 14: ...rosonics Inc or an authorized dealer shipping costs prepaid within one year from the date of purchase This Limited Warranty is governed by the laws of the State of New Mexico It states the entire liab...

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