Uniden PRO 640XL owner manual

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1.MIC GAIN - Adjusts the modulation of the mic for crisp, clear transmission.

2.ANL/NB KEY - Youcan select Noise Blanker and Automatic Noise Limi- ter or all filters OFF. The ANL/NB helps to reduce harsh background noise caused by a variety of interference sources.

3.DIM KEY- The dimmer adjusts the front panel lights for optimum viewing.

4.INSTANT CH 9 and 19 - Press these keys to instantly select either channel. Press again to return to normal 40 channel operation.

5.TXand RXINDICATORS- An LEDlights to indicate when the radio istrans- mitting or receiving.

6.MICROPHONE -The operational mode of the CB is controlled by the push-to-talk switch on the mic. Press the switch to activate the transmitter and disable the receiver. Release the switch to enable the receiver and disable the transmitter. When transmitting, hold the mic about 2 inches

from your mouth and speak clearly in a normal voice. The mic included with the PRO 640XL is a detachable, Iow impedance, dynamic type.

7.S/RF/SWR METER- This LEDmeter shows the relative strength of the re- ceived signal or the RFoutput and the Standing Wave Ratio of your antenna.

8.CHANNEL INDICATOR - Displays the channel currently in use.

9.CHANNELSELECTOR- This switch selects the desired channel for transmission and

reception. Allchannels, except channel 9, may be used for communications.between stations operating under different license. Channel 9 has been reserved by the DOTAC for emergency communications involving the immediate safety of individuals or the immediate protection of property. Channel 9 also may be used to render assistance to a motorist. This is a DOTAC rule and applies to all operators of CB radios.

10.CLARIFIER- Used to fine tune the receive frequency in USB/LSBmodes.

11.RF GAIN - Press this control when strong signals are present to improve sig- nal reception sensitivity.

12.SQUELCH- The Squelch control is used to eliminate background noise dur- ing the absence of a transmission. Turn the control fullycounterclockwise, then slowly rotate it back, clockwise until all noise disappears. At this setting any trans- mission must be slightly stronger than the background noise to "BreakSquelch" or to be heard. Further clockwise rotation will increase the threshold at which a sig- nal will be heard. You can select any level to "Break Squelch"

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Contents Uni en@ Welcome Connecting the Power CordsPage Controls and Functions Pro 640XL Rear Panel Positive Ground System Mobile InstallationMobile Antenna Negative Ground SystemTo Transmit Erating.ProcedurePreventive Maintenance To ReceiveMemo Servicing Your CB Trou bleshooti ngSpecifications Memo Warranty