Ranger RCI-2970DX-50 Marine Radio User Manual


 
- 6 -
Operation
(Continued)
5. SQUELCH CONTROL: This control is used to control or eliminate
receiver background noise in the absence of an incoming signal. For
maximum receiver sensitivity, it is necessary that the control be
adjusted only to the point where the receiver background noise is
eliminated. Turn fully counterclockwise and then slowly clockwise until
the receiver noise just disappears. Any signal to be received must now
be slightly stronger than the average received noise. Further clockwise
rotation will increase the threshold level that a signal must overcome in
order to be heard. Only strong signals will be heard at a maximum
clockwise squelch setting.
6. RF GAIN CONTROL: This control is used to reduce the receiver's front-
end gain when receiving strong signals.
7. CLARIFIER CONTROL: Allows variation of the receive frequency above
and below the selected receive frequency as shown on the display.
This control is intended primarily to tune in SSB signals when
communicating with several stations that may not be exactly on
frequency. It may also be used to optimize AM/FM signals as
described in the operating procedure paragraph. The clarifier can adjust
the receive frequency ±2.5KHz but does not affect the transmit
frequency or the frequency display.
8. MODE SWITCH: This switch allows you to select one of the following
six operating modes: FM, AM, USB, LSB, CW and PA.
9. NB/ANL BUTTON (NB/ANL): The noise blanker (NB) is very effective in
eliminating repetitive impulse noise such as ignition interference. In the
ANL position, the AUTOMATIC NOISE LIMITER also limits noise at the
receiver audio stages.
10. ROGER BEEP BUTTON (R.BEEP): This switch activates the ROGER
BEEP circuit, when its function is selected. When enabled, the radio
automatically transmits an audio tone each time you release the PTT.
This indicates the end of each transmission so that stations who may
- 7 -
Operation
(Continued)
be having trouble receiving will know that you have finished
transmitting. This feature is sometimes used in weak signal conditions
or other special circumstances. We discourage use of this feature in
normal operation, as it can be annoying to other operators.
11. SPLIT BUTTON (SPLIT): Enables the offsetting of the transmitter
frequency by up to ± 2 MHz (programmable) for FM repeater
operation.
12. PROGRAM BUTTON (PRG): Used to pre-program operating or
scanning frequencies into memory. See the OPERATION section of this
manual for details.
13. MANUAL BUTTON (MAN): Used to return the unit to manual mode.
14. SHIFT BUTTON (SHF): Determines which digit will change when
changing frequencies, by placing a “cursor” under the desired digit.
Allows frequency to be changed in 100 Hz, 1KHz, 10KHz, 100KHz and
1 MHz increments.
15. DIM BUTTON (DIM): This button adjusts the display backlighting in
four different steps to best match the ambient light.
16. SWR BUTTON (SWR): Used to check relative SWR.
17. SCAN BUTTON (SCAN): Used to enable the scanning of frequencies.
See the PROGRAMMING and SCANNING section of this manual for
detailed information on using the scan control.
18. MEMORY BUTTON (MEM): Used to program often used frequencies
in memory. Detailed information on how to use this control is provided
in the PROGRAMMING section of the manual.
19. ENTER BUTTON (ENT): Used to program frequencies in memory.
See PROGRAMMING section.