Quansheng UV-K5(8) Compliance Test

Compliance testing to ascertain if this radio meets ITU guidelines for spurious emissions.

 Quansheng UV-K5(8) Grade: PASS

The Quansheng UV-K5(8) amateur radio sample we tested performed well across the 2m band.  On the 70 cm band, we measured one spurious emission exceeding the levels permitted by ITU guidelines by 48 microwatts, which we consider acceptable.

Results were corroborated by testing a second Quansheng UV-K5(8), but it is possible other samples could vary in performance. See the comments at the bottom of this test.

Tests performed in Surrey, BC, Canada on July 6, 2024 by Reg Natarajan.
Discuss this radio on our forums. https://forums.advancedamateur.ca/t/quansheng-uv-k5-8

Power Output Testing

Power output was measured using a Surecom SW-33 Plus into a dummy load. The radio was set to maximum power. The ITU guidelines for spurious emissions require measurements of "the power (W) supplied to the antenna transmission line".  That requirement makes this separate power measurement necessary, as it is incorrect to measure relative to the fundamental (f0).  All numbers have been rounded.

2M

146.520 Mhz

4.8 watts

Using the ITU formula of 43+10log(P) dB, spurious emissions for a signal of 4.8 watts must be at least 49.86 dB below the power supplied to the antenna transmission line.  4.8 watts is approximately 36.9 dBm, which means no spurious signal may exceed -13 dBm, or approximately 50 microwatts.

70cm

446.000 Mhz

3.2 watts

Using the ITU formula of 43+10log(P) dB, spurious emissions for a signal of 3.2 watts must be at least 48 dB below the power supplied to the antenna transmission line.  3.2 watts is approximately 35 dBm, which means no spurious signal may exceed -13 dBm, or approximately 50 microwatts.

Spurious Emissions Testing

Spurious emissions were measured using a Tiny SA Ultra.  The radio was set to maximum power and was connected to the TinySA through an attenuator. It is important to understand that the graphs below are using a decibel scale, not a linear scale.  If a spurious emission spike appears to be almost as tall as the fundamental, that does not mean it is emitting almost as much power.  Refer to the raw data shown. 

VHF 2m Band Test Results: PASS

Raw Data 2m

All numbers have been rounded

Power at Antenna: 36.9 dBm (4.8 watts)

Fundamental (f0): 35.3 dBm (3.4 watts)

2nd Harmonic (2f0): -13 dBm (50 microwatts)

Should be less than -13 dBm (50 microwatts)

3rd Harmonic (3f0): -23.9 dBm (4 microwatts)

Should be less than -13 dBm (50 microwatts)

The Quansheng UV-K5(8) sample that we tested displayed several minor harmonic emissions above the 2m band fundamental, all of which were in compliance with ITU guidelines. The second harmonic of approximately -13 dBm was right on the line of compliance, and subsequent harmonics were well below that line.

UHF 70cm Band Test Results: ACCEPTABLE

Raw Data 70cm

All numbers have been rounded

Power at Antenna: 35 dBm (3.2 watts)

Fundamental (f0): 32.7 dBm (1.9 watts)

2nd Harmonic (2f0): -17.7 dBm (17 microwatts)

Should be less than -13 dBm (50 microwatts)

3rd Harmonic (3f0): -10.1 dBm (98microwatts)

Should be less than -13 dBm (50 microwatts)

The Quansheng UV-K5(8) sample that we tested displayed two significant spurious emissions above the 70 cm band fundamental in our testing, one of which was not compliant with ITU guidelines on spurious emissions.  The third harmonic emission was 45.1 dB below the power measured at the antenna transmission line instead of the required 48 dB which, while technically out of specification, is an acceptable performance in our view.

Comments

I realize that some will disagree with my giving this radio a passing grade given that its third harmonic on 70 cm was technically out of spec, but I just can't see how being 45 dB down instead of 48 makes any difference in the real world.  Obviously, if it was 10 or 20 dB down, that would be another story, but in this case, we're talking about 48 microwatts of excess RF (98 instead of the required 50), which is almost certainly never going to bother anyone.  To me, that's a pass.  If you consider it a fail, that's fine.  We each choose our own labels.

Many thanks to Mike VE7YEG for the use of his radio for testing.  Subsequent testing with my own Quansheng UV-K5(8) (which I purchased to test an aftermarket add-on card) exhibited similar emission levels.  Power on my sample was down significantly on the 2m band to about 4.3 watts, possibly because of the installed aftermarket card.

I also note that, with both samples, power dropped significantly if the PTT was pressed for more than a few seconds.  Pressing the PTT for over 30 seconds dropped total power into the 3.8 watt range.  

~Reg Natarajan VA7ZEB / HJ1ZEB, July 6, 2024


Discuss this radio on our forums.  https://forums.advancedamateur.ca/t/quansheng-uv-k5-8