J SELECTIVITY switch

When an optional filter is installed, the receiver's passband can be switched to one of four different bandwidths by using the SELECTIVITY switch.

The switch has five positions; AUTO, N, M 1, M2 and W, that are used to select the bandwidth. This switch should normally be set to the AUTO position. The IF bandwidth will then be selected for optimum receiver characteristics, according to the MODE that has been selected. Manual override is possible by simple rotation of the SELECTIVITY switch.

The table on page 16 shows the bandwidth of each switch setting. Note the differences when the optional filters are installed.

Caution:

Optional filter should be installed by qualified service personnel to prevent personal injury or damage to the equip- ment.

Note:

When in the FM mode the bandwidth is always 12kHz, regardless of the position of the SELECTIVITY switch.

®SQL (Squelch) control

This control is used to eliminate atmospheric noise, and receiver static noise during no signal periods. Slowly rotate the control clockwise to the point where the ambient noise just disappears, and speaker shuts off. This point is

known as the squelch threshold point. Now you will only hear output from the speaker when an incomming signal is present. For weak signal reception this control should be fully counterclockwise.

Note:

The squelch threshold position will vary from mode to mode, so you may have to readjust when you change mode.

®NOTCH control

The NOTCH function is used to reduce or eliminate hetero- dyne, or CW type signal interference.

If a single tone such as a CW signal is superimposed on the receive signal, turn the NOTCH switch ON and slowly adjust the NOTCH control to eliminate or minimize the beat signal. Normally the NOTCH point will occur between 11:00 and 1:00.

The NOTCH filter will not be effective against SSB, AM or FM type signals, only single tone CW type signals.

In the CW mode, an audio peak filter (APF) is automatically selected; adjust the NOTCH control for the best signal.

In CW, we recommend the use of a CW filter (YK-88C or YK-88CN). When a CW filter is installed, the APF is dis- connected.

Whithout a CW filter installed, APF is connected in CW mode. The APF works in similar fashion as a CW filter.

Note:

The NOTCH function is used to reduce or eliminate hetero- dyne, or CW type signals.

®I F SH I FT control

The IF SHIFT control allows you to shift the IF passband of the receiver, without changing the actual center frequency of the receiver. This control is useful when there is interference near your center frequency.

Interference from lower frequencies can be reduced or eliminated by rotating the IF SHIFT control clockwise. This will cause the resulting audio frequencies to have a slightly treble response, i.e. low cut filter (low frequencies atten- uated). Interference from higher frequencies can be reduced or eliminated by rotating the IF SHIFT control

counterclockwise. This will cause the resulting audio frequencies to sound a little bassy, i.e. high cut filter (high frequencies attenuated).

Note:

The IF SHIFT control does not function in the AM or FM modes.

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