example, if the RF. GAIN control is set for no signal reading of S8 and reads S9 with signal, the received signal is S9.

2.2.2 FSK Operation.

Note

The KWM-2/2A Transceiver has an audio response of 300- to 2400-Hz nominal, therefore any FSK audio input must be between 300 and 2400 Hz.

Usually in RTTY, the FSK signal is an 850-Hz total shift between mark and space signals. This shift is most often obtained by providing a 425-Hz shift to either side of a reference frequency. The reference frequency is the RTTY center frequency. To obtain the 850Hz shift and reference frequency using the KWM-2A, follow the procedures listed below.

Caution

During RTTY operation of the KWM-2/2A a small blower must be directed on the power amplifier cage to permit continuous operation.

1. a. Set the function switch to ON.

2. b. Connect a 1275- and 2125-Hz 2-tone keyer .50 Hz difference - both frequencies in the :S00- to 2400-Hz audio response of the KWM-2/2A) to the teletypewriter.

3. c. Connect the keyer audio output to the KWM-2\2A audio input and the . KEM-2/2A audio output to the converter audio input. Adjust the keyer audio output level to provide an audio output level Between 25 and 100 millivolts to the KWM-2/2A.

4. d. Set up receiver and transmitter operation at 1700 Hz above the desired RTTY center frequency operation. Refer to paragraphs 2.3 and 2.4.1. Set EMISSION switch to LSB.

5. e. Normally the 2-tone keyer provides A ptt key. If a ptt key is not provided, key the teletypewriter and increase the VOX GAIN control setting until the VOX relay just operates.

6. t. Using a phone plug, solder a connection from 1ho inner conductor to the outer conductor.

Connect this plug to the ALC phone jack (J4) to provide a short to ground for the ALC line.

1. g. Set meter switch to CRTL) position. Adjust setting of MIC GAIN control for S3 meter indication of grid current.

2. h. Adjust the R.F. GAIN control full clockwise. Adjust the AF GA1N control for the amount of receive power required by the converter. If audio is monitored, this should provide a comfortable monitoring level.

   Note

   These procedures are for high mark and low space RTTY operation. For additional information on FSK operation, refer to RTTY Operation of KWM-2/2A and S-I,ine Equipment Instruction Sheet 523-0182000.

VOX and anti VOX circuits will operate in mobile operation, but push-to-talk operation is ecommended, since high-level background noises will produce undesirable VOX switch over. Set VOX GAIN and ANTIVOX GAIN controls full counterclockwise before installation. If VOX operation is desired, leave clearance in installation so top cover can be opened. For mobile operation, load the power amplifier to 210-mA plate current. (In some installations, power amplifier plate current readings less than 210 mV will he obtained due to cable length, cable size, and battery condition.)

2.5 OPERATION OUTS1DE AMATEUR BANDS

2.5.1 Selection of Crystals

The crystals supplied provide for complete coverage of all amateur bands except the 10 meter band for which only one crystal is furnished for 28.5 to 28.7 MHz). Two extra sockets are provided for additional crystals in the 10-meter band. figure 2-3 shows crystal socket locations. Select these crystals as follows:

1. a. If the lower edge of the desired 200-kHz band is 11.8 MHz or less, the required frequency is equal to the lower edge of the desired hand plus 3.155 MHz. As an example