N6EX Exciter Performance

• PLL Control Voltage (Verify between 1.0 and 7.0 volts)
• Transmit Frequency (Adjust TCXO A/R to within 50 Hz)
• Power Output
• Audio Input Level
• Maximum Deviation
• PL/DPL Level/Balance
• Current Consumption

Notable Exciter Measurements

Current Consumption

• Idle: 378 mA (at 13.5 VDC)
• Transmit: 1.29 A (at 13.5 VDC)

Power Output

• 2.15 Watts
• 1.99 Watts after 45 minutes continuous transmit

Wideband Spurious and Harmonic Rejection

click for larger image (28KB)

Spectrum analyzer plot showing the rejection levels of the half-harmonic and second harmonic. Observations after this plot was taken indicate that the analyzer may have been somewhat overloaded during this measurement, leading to higher indications of spurious responses than actual. Spurious and harmonic rejection of the TK-931 is specified as 65 dB minimum. Future measurements will be performed and the plot updated.

Narrowband Spurious Rejection

click for larger image (28KB)

Spectrum analyzer plot showing close-in synthesizer spurious responses.

Close-In Spectrum and Frequency Accuracy

click for larger image (28KB)

Analyzer plot showing the close-in spectrum with only the DPL modulation. This plot also shows a transmit frequency setting of approximately 250 Hz above the 927.1375 center frequency. The yellow trace is an instantaneous plot while the green trace is a maximum hold plot.

Transmit Audio Frequency Characteristics

click for larger image (32KB)

Audio response of the exciter closely follows the standard 6 dB per octave pre-emphasis curve.