#USE AUDIOLEVEL FOR IMAGEALPHA GENERATOR#
#USE AUDIOLEVEL FOR IMAGEALPHA SOFTWARE#
#USE AUDIOLEVEL FOR IMAGEALPHA PLUS#

From the asterisk CLI, type rpt fun yournodenumber #.

Adjust the tx level until the service monitor indicates 3kHz of peak deviation.

The transmitter should key and you may hear a tone.

From the asterisk CLI, type rpt fun yournodenumber *989В where yournodenumberВ is the node number assigned to you.

Connect the radio interface to the transmitter.

#USE AUDIOLEVEL FOR IMAGEALPHA GENERATOR#

Enable the test tone generator in rpt.conf and restart Asterisk.

Disable CTCSS tone generation in the transmitter or at the CTCSS encoder.

If it is more than this, adjust the CTCSS level so that a reading of 3.6kHz is attained.

Check that the peak deviation is no more than 3.6 kHz.

Re-enable the generation of CTCSS tones in the transmitter.

The audio waveform should now be a sine wave with no evidence of limiting.

Reduce the level of the audio signal generator so that the service monitor reads 3kHz of peak deviation.

It should show evidence of hard limiting (it should look like a square wave with rounded edges) Check the shape of the audio waveform on the service monitor's scope.

If the peak deviation is more than 5kHz, then adjust the transmitter deviation pot or soft pot so that the peak deviation reading on the service monitor is no more than 5kHz.

Make a note of the peak deviation at this point. Gradually increase the output of the audio signal generator until further adjustment does not increase the deviation.

On the service monitor, monitor the peak deviation of the transmitter.

Hook up the service monitor to the transmitter RF output (with appropriate attenuation for protection of your Service Monitor) and key the transmitter.

Hook up the audio signal generator to the transmitter microphone input, set it for a 1kHz sine wave, and the lowest output setting.

(If you don't encode CTCSS, skip this step and steps 6 and 7)

Disable the generation of CTCSS tones in the transmitter.

If you driving the modulator directly from a URI, this section can be skipped. If you intend to drive the transmitter at the microphone input, or at another audio input before pre-emphasis and limiting, you must ensure that the peak deviation of the transmitter is no more than what is required to operate on the channel (typically 5KHz). Procedure Checking the Radio's Transmitter's Peak Deviation

You must know the node number and the channel number of the radio port you wish to test.

So the step below which say to use 3kHz should use 1.5kHz.

For narrow band systems everything is half.

The system you are calibrating uses 5khz deviation (standard nbfm) as the maximum peak deviation.

#USE AUDIOLEVEL FOR IMAGEALPHA SOFTWARE#

Tweaking tools if your radio or interface board have physical adjustment pots, or the appropriate service software for your radio.

Terminal access to the machine being calibrated.

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HP 8920, IFR1200, or a separate signal generator and deviation meter), plus cabling. A service monitor, preferably one capable of simultaneous generation and analysis (e.g.An asterisk app_rpt.c compiled with Asterisk and installed.To properly perform the audio level calibration, you will need the following items: Fortunately, the procedure is not that complicated.

Proper audio level calibration is crucial for ensuring good audio quality, and consistent audio levels from node-to-node.

3.1 Checking the Radio's Transmitter's Peak Deviation.

Use audiolevel for imagealpha