Kenwood TS-440S manual Afsk, Mode, Operation with a Linear AMPLI- Fier, Crowded

3-8. AFSK

3-8-1. Reception

Note:

An RTTY terminal is required to receive and dis- play/print the RTTY signal.

1.The AFSK mode utilizes the LSB carrier frequency, which conforms to international conventions.

2.When the optional YK-88C filter is installed, the nor- mal receiver bandwidth is 500 Hz when the SELEC- TIVITY switch is set to the AUTO position, and the MODE switch is in AFSK.

The accompanying diagram illustrates the relation- ship between the carrier and the passband width.

3.The demodulated AFSK signal is sent from the AFSK OUT terminal on the rear panel.

4.This completes the preparation for using the AFSK

mode.

Note: - Before connecting the terminal you should review the contents of the instruction manual provided with that terminal unit.

-z- -z-

RTTY

wave

(F1 )

The figure below shows the frequencies relationship.

2295Hz

of the TS-440S. (See page 11 for the REMOTE ter- minal pin configuration.)

3.Place the MODE key on the TS-440S to AFSK, and the Meter switch to ALC.

4.To transmit, either place the SEND/REC switch on the TS-440S to SEND, or use the PTT signal from your terminal unit.

5.When using AFSK, you can also apply your trans- mit signal tones to pin number 1 of the microphone connector, if you do not wish to use the two jacks on the rear of the TS-440S. To adjust the power output in AFSK, increase or decrease the MIC gain control setting. A mid-scale ALC reading will yield full power output.

Notes:

1.AFSK operation requires terminal unit designed to supply this type of operation. You cannot use FSK tones with an AFSK jack!

2.The AFSK oscillator circuit should provide audio tones of 2125 and 2295 Hz. Lower tones may cause spurious output due to the higher harmonic content present with these lower frequencies.

3.The TS-440S and RTTY terminal unit should use separate power supplies, in order to prevent RFI (Radio Frequency Interference).

4.During AFSK mode operation, the microphone switch should be OFF or ground pin No.9 of the ACC 2 jack, or the microphone disconnected, if you are using the AFSK jacks on the rear panel.

5.The AFSK input level should be less than 100 mV.

3-8-3. AMTOR operation

For AMTOR operation, you should reverse the trans- mit/receive input polarity on your AMTOR terminal, since AFSK on the TS-440S operates in the LSB mode. If you cannot reverse the polarity, you should select the USB mode on the TS-440S.

During AMTOR operation, the microphone switch should be OFF, or ground pin No.9 of the ACC 2 jack, orthe microphone disconnected, if you are using AFSK IN/OUT jacks on the rear panel.

3-8-2. Transmit

Note:

Key down periods of 1 hour will require q cool down period of approximately 30 minutes. The PS-50 heavy-duty supply is recommended for continuous duty transmission.

1.Ensure that your terminal is set up for AFSK type keying.

2.Connect the terminal units AFSK output jack to

\TS-440S AFSK IN jack, and the terminal unit's AFSK input jack to the TS-440S AFSK OUT jack

on the rear panel of the transceiver. The terminal units standby (PTT) terminal should be connected to the standby terminal on the REMOTE connector

3-9. OPERATION WITH A LINEAR AMPLI- FIER

The TS-440S may be operated with any conventional linear amplifier which will accept up to approximately 125 watts of RF drive, has a low current DC operated

keying circuit, and returns approximately -8 to -1 VDC ALC back to the exciter. Please note that in ord- er to operate full aSK (FULL break-in) the linear ampli- fier must also be aSK capable.

Refer to the REMOTE connector diagram on page 11 and section 5-8-10..

Initial linear amplifier tune-up should be performed with

the TS-440S set for approximately 50 watts output to reduce wear and tear on both the linear, and the

TS-440S. Use of a dummy load is strongly recom- mended, since the bands are already sufficiently

crowded.

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