ICOM 217800 Manuale Utente

BASIC OPERATION

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Squelch and receive (RF) sensitivity

Adjusts the RF gain and squelch threshold level. The
squelch removes noise output from the speaker
(closed position) when no signal is received.

• The squelch is particularly effective for FM. It is also avail-

able for other modes.

• 12 to 1 o’clock position is recommended for any setting of

the [RF/SQL] control.

• The control can be set as ‘Auto’ (RF gain control in SSB,

CW and RTTY; squelch control in AM and FM) or squelch
control (RF gain is fixed at maximum) in set mode as fol-
lows. (p. 98)

Adjusting RF gain

(Receive sensitivity)

Normally, [RF/SQL] is set to the 11 o’clock position.
Rotate [RF/SQL] to the 11 o’clock position for maxi-
mum sensitivity.

• Rotating counterclockwise from the maximum position re-

duces sensitivity.

• The S-meter indicates receive sensitivity.

Adjusting squelch

(Removing non-signal noise)

Rotate [RF/SQL] clockwise when receiving no signal,
until the noise just disappears.

• [RX] indicator light goes out.
• Rotating [RF/SQL] past the threshold point invokes the S-

meter squelch— this allows you to set a minimum signal
level needed to open the squelch.

• When setting as RF gain/squelch control

• When functioning as RF gain control

(Squelch is fixed open; SSB, CW, RTTY only)

• When functioning as squelch control

(RF gain is fixed at maximum.)

While rotating the RF gain control, noise may be
heard. This comes from the DSP unit and does not
indicate an equipment malfunction.

Squelch is
open.

S-meter
squelch

S-meter squelch
threshold

Noise squelch
threshold
(FM mode)

Shallow

Deep

Noise squelch (FM mode)

Minimum RF gain

Adjustable
range

Maximum
RF gain

Recommended level

RF gain
adjustable
range

Maximum
RF gain

S-meter
squelch

Noise squelch (FM mode)

Squelch is
open.

[RF/SQL]

SET MODE

OPERATION

RF+SQL

Can be used in all modes.

(default)

Functions as noise squelch or S-meter
squelch in AM and FM modes; S-
meter squelch only in other modes.

SQL

Operates as a squelch control.

• RF gain is fixed at maximum sensitivity.

Operates as an RF gain control in
SSB, CW and RTTY modes.

AUTO

• Squelch is fixed open.

Operates as a squelch control in AM
and FM modes.

• RF gain is fixed at maximum sensitivity.