After completing the internal tuner add-on for my K1, I wanted to run emission tests on it as well. My unit is two bands: 30-meter and 20-meter.
FCC Limit: For transmitters installed after January 1, 2003, the mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency below 30 MHz must be at least 43 dB below the mean power of the fundamental emission.
Test Setup: UUT feeds a 50 dB Power Attenuator, the output of which is feeding a Siglent SSA3021X Spectrum Analyzer. The SA calibration is valid through November of 2017.
Test Settings for Carrier Noise: For close in viewing, span is 10 KHz, centered on transmit frequency. RBW/VBW 100 Hz. On 10.125 MHz, 30-meters, Input Power to SA was 50 – 13.36 dBm, or 36.74 dBm (4.72 watts). TX noise is -73 dBc.
On 14.050 MHz, 20-meters, Input Power to SA was 50 – 12.35, or 37.65 dBm (5.82 watts). TX noise is – 76 dBc.
Worst Case Spurious Emission 30-Meters: The worst-case emission on 30-meters was the 6th Harmonic. This was -54.20 dBm, or -41.1 dBc which does not pass. However, this was with the antenna tuner bypassed, which would add additional harmonic rejection, especially at higher frequencies.
Worst Case Spurious Emission 20-Meters: The worst-case emission on 20-meters was actually 630 KHz above the carrier at -58.84 dBm. This is -46.6 dBc, passing. The second harmonic was at -64.76 dBm, or -52.5 dBc. Higher harmonics were not visible.
