Radio Alignment Procedures: Transmitter Alignment Options

5-7

 

 

5.4.4VCO Attenuation

Note: Modulation Balance Tuning must be done first. The Transmit Deviation Limit softpot sets the maximum deviation of the carrier. Tuning is performed for all (12.5 kHz, 20 kHz and 25 kHz) channel bandwidths. Tuning for 25 kHz channels must be done first for all frequency points. Tuning for 12.5 and 20 kHz channels determines only the off- set to the previously tuned deviation for 25 kHz tuning channel spacing. For 12.5, and 20kHz channels, only the last non-0 transmit frequency point (normally F7) is used for tuning. The 30 kHz channel bandwidths that use 5.0 kHz maximum system devia- tion are covered by the 25 kHz tuning.

When using test box RLN4460:

•Set the METER OUT toggle switch to the “MIC PORT” position

•Set the METER OUT selector switch to “MIC”.

•Inject a 1 kHz tone with the levels given below for each radio model to AUDIO IN.

•Measure the level at the radio input at the AC/DC meter.

Figure 5-6. VCO Attenuation Window (12.5 kHz)

5.4.4.1VCO Attenuation 25 kHz

1.Under the Tx Align menu, select VCO Attenuation 25 kHz (Figure 5-6).

2.Begin with the lowest frequency. Select the thumb of the slider at the lowest frequency point and then press the PTT Toggle button to key up the radio at the corresponding frequency point. The spin control can also be toggled via its up/down arrow buttons. The softpot value can also be typed into the edit control (press ENTER to confirm your selection/send a softpot value).

3.Inject 1 kHz at an appropriate level until 2.3 V rms is measured at the AC/DC METER (radio input) if using test box RLN4460.

4.Record the deviation obtained.

5.Adjust the slider; adjust the spin control or key in softpot values (press ENTER to confirm) for the frequency point until the deviation is within the range specified in Table 5-4.

6.Dekey the radio (Press the PTT Toggle button). Choose the next frequency, key up and repeat steps 3 to 6 until all seven tuning points are done.

HKLN4215A

December 3, 2003

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Motorola EP450 service manual VCO Attenuation 25 kHz, When using test box RLN4460
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EP450 specifications

The Motorola EP450 is a robust and reliable two-way radio that has made a significant impact in the world of professional communications. Known for its solid construction and exceptional performance, the EP450 is a popular choice among various industries, including security, transportation, and event management.

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In conclusion, the Motorola EP450 stands out for its superior audio quality, versatile frequency operation, long-lasting battery life, and rugged design. These features make it an indispensable tool for professionals who require reliable communication in demanding environments, proving its value across a multitude of industries.
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