Icom IC-7851 - D Setting the Decoder Threshold Level

5-28
5
RECEIVE AND TRANSMIT
Operating PSK (Continued) 
D
Setting the decoder threshold level
Adjust the PSK decoder threshold level if some charac-
ters are displayed even, though no signal is received.
q Display the PSK decode screen, then push [ADJ](F).
DECODE [F-3]  ADJ [F-5]
• The threshold setting screen is displayed.
Rotate [MAIN DIAL] to adjust the PSK decoder w
threshold level.
• Hold down [DEF](F) for 1 second to select the default
setting.
Push [EXIT/SET]. e
• Exits the Setting screen.
[EXIT/SET] [MAIN DIAL](F) Function keys
D
About the PSK reverse mode
If the received signal is not properly demodulated, try
selecting the PSK-R mode.
In the QPSK mode, the phase shift direction must be
the same on the transmitter and the receiver sides. To
receive the reverse direction signal, select the PSK-R
mode to match the phase shift direction to the trans-
mitter side.
In the PSK mode, hold down [RTTY/PSK] for 1 sec- 
ond to select the PSK and PSK-R modes.
D
AFC/NET functions
The IC-7851 has an AFC (Auto Frequency Control)
function. This is convenient to tune the PSK signal.
The IC-7851 also has a NET function that transmits
the PSK signal tuned by the AFC function.
In the PSK decode screen, push [AFC/NET](F). 
• Push [AFC/NET](F) selects these functions.
“
” (AFC ON)  “ ” and “ ” (AFC/NET ON)
 (The icons disappear) 
“ ” (AFC ON)    
• When “ ” or “ ”and “ ” are displayed, dis-
plays the frequency offset between the operating fre-
quency and the PSK signal.
• The AFC tuning range is set to ±15 Hz by default. You
can select a ±8 Hz setting in the PSK decode set mode.
(p. 5-34)
When the frequency offset is displayed, hold down 
[AFC/NET](F) for 1 second to add the frequency off-
set to the operating frequency.
Mode keys
AFC, NET icons Frequency offset
NOTE: The AFC function may not tune the signal
properly when a weak PSK signal is received.