Kenwood TS-870S User Manual - Page 76

12 MAINTENANCE INTERNAL ADJUSTMENTS REFERENCE FREQUENCY CALIBRATION Note: The transceiver is adjusted at the factory prior to shipping. Unless necessary, DO NOT perform this adjustment. 1 Remove the top case (10 screws) from the transceiver. 2 Set the following on the transceiver: • Mode: CW • MONI control: Center • AF gain control: Center • Menu No. 24 (CW PITCH): 800 Hz • HI/SHIFT control: 800 Hz • LO/WIDTH control: 1000 Hz • RIT function: OFF • Break-in Function (VOX): OFF 3 Tune in a standard frequency station such as WWV or WWVH at, for example, 10.000 or 15.000 MHz. Adjust the transceiver Tuning control so the Display reads the exact frequency of the station. You should hear a beat tone of approximately 800 Hz. For 800 Hz: faf = (fdisplay/20.000 x ∆freference) + 800 Hz where ∆freference is the shift from the 20 MHz reference frequency 4 Close your CW key and you will hear a transmit sidetone of approximately 800 Hz. This sidetone produces a double beat tone when it combines with the received signal. Adjust the AF gain control and the MONI control so you can hear the double beat clearly. For 800 Hz: fsidetone = 800 Hz x [(20 x 106 + ∆freference)/20 x 106] where ∆freference is the shift from the 20 MHz reference frequency 5 Adjust the TC-800 trimmer to minimize the frequency difference between the received 800 Hz tone and the 800 Hz sidetone. Remove the top case. DRU-3 DIGITAL RECORDING UNIT (OPTIONAL) RECORD LEVEL ADJUSTMENT Remove the bottom case. VR3 AT-300 EXTERNAL TUNER (OPTIONAL) FUSE LOCATION Remove the top case. Fuse for AT-300 TC-800 70