C2R-PPR-125CB TRANSCEIVER

PPR-125 40 Channel AM Mobile CB Radio OWNER’S MANUAL - 1 - CONTENS A PAGE Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Mounting The Radio . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Ignition Noise Interference . . . . . . . . . . . . . . . . . . . . . . . 4 Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Tuning The Antenna for Optimum SWR . . . . . . . . . . . . . 5 External Speaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Public Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Frequency Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Procedure to Receive And Transmit . . . . . . . . . . . . . . . . 11 Alternate Microphone And Installation . . . . . . . . . . . . . . 12 Maintenance And Adjustment . . . . . . . . . . . . . . . . . . . . 15 A Few Rules That Should Be Obeyed . . . . . . . . . . . . . . 16 How Your CB Can Serve You . . . . . . . . . . . . . . . . . . . . . 16 - 2 - SPECIFICATIONS A GENERAL Model PPR-125 Channels 40 Frequency Range 26.965 ~ 27.405 MHz Emission AM Frequency Control Phase-Lock-loop (PLL) Synthesizer Frequency Stability 0.001% Temperature Range -30 “ C to +50 “ C Antenna Impedance 50 Ohms Antenna Connectors Standard SO-239 type Input Voltage 13.8V DC Size 7- 3/8” (W) x 8- 3/4” (D) x 2- 1/4” (H) Weight 4.2 lbs. TRANSMITTER RF Power Output 4W Spurious Emission -60 dB Audio Distortion 10% Frequency Response 300 to 2500 Hz Microphone Dynamic RECEIVER Sensitivity for 10 dB (S+N)/N < 1.0 uV Squelch Sensitivity < 0.5 uV Image Rejection More than 65 dB AGC Figure of Merit 100 mV for 10dB Change in Audio Output Audio Power Output 3W @ 10% Distortion Audio Response 300 to 2500 Hz (SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE) - 3 - INSTALLATION A LOCATION Plan the location of the transceiver an d microphone bracket before starting the installation. Select a location that is conven ient for operation and does not interfere with the drive or passengers in the automobiles, the transceiver is usually mounted the dash panel with the microphone bracket beside it. MOUNTING THE RADIO The transceiver is supplied with a universal mounting bracket. When mounting the bracket and radio to your car, make sure it is mechanically strong. Also provide a good electrical connection to the chassis of the vehicle. Proceed as follows to mount the transceiver: 1. After you have determined the most convenient location in your vehicle, hold the transceiver with mounting bracket in the exact location desired. If nothing will interfere with mounting it in the desired position remove the mounting bolts. Before drilling the holes, make sure nothing will interfere with the installation of the mounting bolts. 2. Connect the antenna cable plug to the stan dard receptacle on the rear panel. Most transceiver antennas are terminated with a type PL-259 plug and mate with the receptacle. 3. Connect the red DC power input wire (with the fuse) to +13.8V DC. This wire extends from the rear panel. In automobile installation, +13.8V DC is usually obtained from the accessory contact on the ignition sw itch. This prevent the set being left on accidentally when the driver leaves the ca r and also permits operating the unit without the engine running. Locate the accessory co ntact on most ignition switches by tracing the power wire from the AM broadcast receiver in the car. 4. Connect the black lead to –13.8V DC. This is usually the chassis of the car. Any convenient location with g ood electrical contact (remove paint) may be used. 5. Mount the microphone bracket on the right side of the transceiver, using two screws supplied. When mounting in an automobile, place the bracket under the dash so that microphone is readily accessible. - 4 - INSTALLATION A IGNITION NOISE INTERFERENCE Use of a mobile receiver at low signal leve ls is normally limited by the presence of electrical noise. The primary source of noise in automobile installation is from the generator and ignition system in the vehicle. Under most operating conditions, when signal level is adequate, the background noise does not present a serious problem. Also, when extremely low leve l signals are being received, the tr ansceiver may be operated with vehicles engine turned off. The unit requires very little current and therefore will not significantly discharge the vehicle battery. Even though the transceiver has ANL and NB controls, in some installation ignition interference may be high enough to make good communications impossible. The electrical noise may come from several sources. Many possibilities exist, as variations between vehicles require different so lutions to reduce the noise. ANTENNA A vertically polarized, quarter-wavelength whip antenna provides the most reliable operation and greatest range. Shorter, loaded-t ype whip antennas are more attractive, compact and adequate for a pplications where the maximum possible distance is not required. Also, loaded whips do not present the problems of high wind resistant imposed by a full quarter-wavelength whip. Mobile whip antennas utilize the metal body of the vehicle as a ground plane. When mounted at a corner of the vehicle they are slightly directional, in the direction of the body of the vehicle. For all practical purpose, howe ver, the radiation pattern is nondirectional. The slight directional characteristic will be ob served only at extreme distances. A standard antenna connector (type SO-239) is provided on the…

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PPR-125 CIRCUIT DESCRIPTION 1.0 INTRODUCTION This section explains the technical theory of operation for the PPR-125 mobile CB radio 1.1 PLL CIRCUIT The Phase Lock Loop (PLL) circuit is responsible for developing the receiver’s first local oscillator signal and the transmitter’s exciter signal. The PLL circuit consists primarily of IC1, Q15, Q16, Q19, Q20 and D12. The PLL circuit is programmed by the up/down channel switch. The channel switch communicates the correct binary data information to the programmable divider inside of IC1. IC1 then controls the VCO (Voltage Controlled Oscillator) to oscillate on the correct frequency. This signal is fed either into the receiver’s first mixer (for receive operation) or the transmitter’s mixer (for transmit operation). 1.2 RECEIVER CIRCUIT The incoming RF signal comes into the radio via the antenna and into the front-end pre-amp, Q9. The RF signal is fed into the mixer circuit of Q10/Q11 and then into the AM IF section of the receiver (Q12 Q13). The signal is then detected by the AM detector and then fed to the audio amplifier section of the receiver (Q14 IC2) and finally outs to the speaker. 1.3 TRANSMITTER MODULATION CIRCUIT (1) The transmitter modulation circuit modulates the low-level RF signal from the PLL exciter circuit with the user’s audio voice signal from the microphone. The audio from the microphone is then amplified (Q34) and fed into the transmit amplifier circuit. (2) If the transceiver is in the AM mode, the AF power (IC2) amplifier modulates the last RF amplifier, which produces a true amplitude modulated RF signal. 1.4 TRANSMITTER AMPLIFIER CIRCUIT The transmitter takes the basic exciter signal from the TX mixer and amplifies it through a series of amplifiers consisting of Q21, Q22, Q23 and Q24 where it is sent out to the antenna connector.

1 PPR-125 ALIGNMENT (EPT012510B) 1.0 TEST EQUIPMENT 1.1 PLL SYNTHESIZER / OSCILLATOR FREQUENCY ALIGNMENT ITEM CONNECTS & SETTING ADJUST MEASUREMENT ± ± ± 1.2 TRANSMITTER ALIGNMENT 2 ITEM CONNECTS & SETTING ADJUST MEASUREMENT ± 1.3 RECEIVER ALIGNMENT 3 ITEM CONNECTS & SETTING ADJUST MEASUREMENT ’ 4