The Full Review of the Elecraft K-1 Transceiver
For the ARS Lab
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Transmitter Tests
Power Output
With a 13.8 volt power supply, our sample produced an output of 5.5 watts on 40 meters and 5.75 watts on 20 meters. With a 12.0 volt power supply, our sample produced an output of 5.0 watts on 40 meters and 4.0 watts on 20 meters.
Power Requirements on Transmit
With a 13.8 volt power supply, our K-1 drew 940 mA on 40 meters and 940 mA on 20 meters. With a 12.0 volt power supply, our K-1 drew 1.14 amps on 40 meters and 900 mA on 20 meters.
Spectral Purity
FCC regulations require the spurious emissions from a 5 watt radio to be at least 40 dB below the carrier. For a radio running less than 5 watts, the regulations require the spurious emissions to be at least 30 dB below the carrier.
Our K-1 easily met both requirements on both 40 and 20 meters (although we did not have an opportunity to test the revised bandpass filter on 20 meters).
Here is the link to the 40 meter spectral purity graph for our sample.
Keying
The K-1 had an excellent keying waveform, as shown on this oscilloscope trace.
Introduction to Receiver Tests
Many of our receiver test reports use bar charts that compare the unit being reviewed to a number of other HF transceivers. Please read this brief explanation of the purpose and layout of these charts.
Receiver Tests—When No External Signals are Present
Tuning Range
The tuning range for our sample had been fine tuned by the constructor. On 40 meters it was 7.0 to 7.070 MHz, and on 20 meters it was 14.0 to 14.065 MHz.
Frequency Stability
Our K-1 drifted 128 Hz during the first 30 minutes of operation on both 40 meters and 20 meters.
Spurious Signals
There was one birdy in our sample, at 14.055 MHz.
Power Requirements on Receive
Our sample drew 58 mA on receive with both a 13.8 and 12.0 volt power supply.
Receiver Tests—When One External Signal is Present
Minimum Discernible Signal
On 40 meters we measured an MDS of -131 dBm. We also measured an MDS of -131 dBm on 20 meters, although our sample did not have the modified 20 meter bandpass filter. Please follow this link for comparisons with the MDS of other HF radios.
Phase Noise
We measured phase noise of -124 dBc/Hz at a spacing of 10 kHz from the carrier. Please follow this link for comparisons with the phase noise of other HF radios.
IF Rejection
Our sample's IF rejection was 80 dB. Please follow this link for comparisons with the IF rejection of other HF radios.
Image Rejection
Our K-1's image rejection was 79 dB. Please follow this link for comparisons with the image rejection of other HF radios.
Audio Output
Our sample produced 1.5% total harmonic distortion at full volume into a pair of stereo headphones.
Receiver Tests—When Multiple Signals are Present
Selectivity
We measured the following 6 dB IF and AF responses for our sample:
Filter #1—420 Hz
Filter #2—390 Hz
Filter #3—260 Hz
You will find interesting information about the width and shape of the K-1's IF and RF response in this AF spectrum analyzer graph.
Blocking Dynamic Range
Our K-1 had a blocking dynamic range of 106 dB. Please follow this link for comparisons with the blocking dynamic range of other HF radios.
In-band IMD
The K-1 had a clean response to the In-Band IMD test. Here is the link to the K-1's AF spectrum analyzer graph.
Two Tone Intermodulation Distortion Tests
Third Order IMD Dynamic Range: 84 dB. Please follow this link for comparisons with the Third Order Dynamic Range of other HF radios.
Third Order IMD Intercept Point: -5 dBm Please follow this link for comparisons with the Third Order IMD Intercept Point of other HF radios.
Second Order IMD Dynamic Range: 95 dB Please follow this link for comparisons with the Second Order IMD Dynamic Range of other HF radios.
Second Order IMD Intercept Point: 54 dBm Please follow this link for comparisons with the Second Order IMD Intercept Point of other HF radios.
The Receiver Factor
The K-1 received a score of -22.1 in the receiver factor calculation. Please follow this link for comparisons with the receiver factor scores of other HF radios.
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