Adjustments

The adjustments page has 5 slider type adjustments, BACKLIGHT, ALARM, VOLUME, SQUELCH and TONE.

The BACKLIGHT adjustment controls the brightness of all parts of the screen. The screen can easily be seen in bright sunlight. When the InfraSignal Radio is battery operated, reducing the BACKLIGHT will increase the battery life.

The ALARM adjustment controls the alarm threshold. Its value is displayed on the sliding scale and also displayed numerically in red above the sliding scale. The value is also displayed at the top of the SIGNAL LEVEL bar graph on the mode pages. When the alarm is disabled, the red numerical value at the top of the SIGNAL LEVEL bar graph on the mode pages is replaced with two red dashes.

The VOLUME adjustment controls the volume of the speaker and the gray colored headphone output on the right side of the radio. When using the AUDIO ON VU METER mode, audio can be heard on the black colored infrasignal output jack, also on the right side of the radio. Please take note. This output is quite loud in the headphones. It is set to a fixed level for recording and is not controlled by the VOLUME adjustment.

The SQUELCH adjustment silences the speaker when the signal level drops below the adjusted squelch value. This eliminates all unnecessary noise from the speaker. The headphone output is not affected by the squelch adjustment.

About the TONE adjustment. All sounds at and below about 20 Hertz (cycles) cannot be heard by the human ear. In order to hear these sounds, i.e., infrasound, a higher frequency tone has to be added to the infrasound to increase it up to the audio frequency range. The infrasound modulation rate and amplitude are faithful preserved.

This tone adjustment is provided for the convenience and preference of the person monitoring the infrasound.