Baofeng UV-21 Compliance Test

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

Baofeng UV-21 Final Grade: Fail

The performance of the Baofeng UV-21 amateur radio sample we tested exhibited significant variability depending on the operating frequency band. It generated multiple spurious emissions above the 2m (144 MHz) band fundamental that were not in compliance with ITU guidelines for such emissions. Performance in the 70 cm (440 MHz) band was fully compliant. Performance in the 1.25m band (220 MHz) was acceptable.

Use of this radio primarily for 2m VHF transmission is dubious. Use of this radio primarily for 1.25m (220 MHz) or 70 cm UHF transmission is more credible.

It is important to note that this was a single-sample test and that it is possible other samples could vary in performance.

Tests performed in Surrey, BC, Canada on July 13, 2024 by Reg Natarajan.
Discuss this radio on our forums. https://forums.advancedamateur.ca/t/baofeng-uv-21

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

5.4 watts

Using the ITU formula of 43+10log(P) dB, spurious emissions for a signal of 5.4 watts must be at least 50.3 dB below the power supplied to the antenna transmission line. 5.4 watts is approximately 37.3 dBm, which means no spurious signal may exceed -13 dBm, or approximately 50 microwatts.

70cm

446.000 Mhz

4.5 watts

Using the ITU formula of 43+10log(P) dB, spurious emissions for a signal of 4.5 watts must be at least 49.5 dB below the power supplied to the antenna transmission line. 4.5 watts is approximately 36.5 dBm, which means no spurious signal may exceed -13 dBm, or approximately 50 microwatts.

1.25M

223.500 Mhz

6.0 watts

Using the ITU formula of 43+10log(P) dB, spurious emissions for a signal of 6.0 watts must be at least 50.8 dB below the power supplied to the antenna transmission line. 6.0 watts is approximately 37.8 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: Fail

Raw Data 2m

All numbers have been rounded

Power at Antenna: 37.3 dBm (5.4 watts)

Fundamental (f0): 35.8 dBm (3.8 watts)

2nd Harmonic (2f0): 16.56 dBm (45 milliwatts)

Should be less than -13 dBm (50 microwatts)

Random Spur (365 MHz): -9.9 dBm (102 microwatts)

Should be less than -13 dBm (50 microwatts)

3rd Harmonic (3f0): -7 dBm (200 microwatts)

Should be less than -13 dBm (50 microwatts)

Random Spur (513 MHz): -10.6 dBm (88 microwatts)

Should be less than -13 dBm (50 microwatts)

4th Harmonic (4f0): -8.3 dBm (147 microwatts)

Should be less than -13 dBm (50 microwatts)

The Baofeng UV-21 sample that we tested displayed three harmonic emissions and two random spurs above the 2m band fundamental, all of which were out of compliance with ITU guidelines. Any spurious emissions should be at least 50.3 dB below the power measured at the antenna transmission line. The UV-21's second harmonic was just 20.74 dB below, which is well out of specification.

UHF 70cm Band Test Results: PASS

Raw Data 70cm

All numbers have been rounded

Power at Antenna: 36.5 dBm (4.5 watts)

Fundamental (f0): 35 dBm (3.2 watts)

The Baofeng UV-21 sample that we tested displayed no significant spurious emissions above the 70 cm band fundamental in our testing.

220 1.25M Band Test Results: ACCEPTABLE

Raw Data 1.25M

All numbers have been rounded

Power at Antenna: 37.8 dBm (6.0 watts)

Fundamental (f0): 36.2 dBm (4.2 watts)

2nd Harmonic (2f0): -8.5 dBm (141 microwatts)

Should be less than -13 dBm (50 microwatts)

The Baofeng UV-21 that we tested displayed one harmonic emission above the fundamental in the 1.25m band. This emission was 46.3 dB below the power measured at the antenna transmission line which, while technically out of specification, is an acceptable performance in our view.

Comments

This report will satisfy nobody. The Baofeng haters will say that I should have flunked it on 220 because it was in violation by 91 microwatts. The Baofeng apologists will say that a 45 milliwatt spur on VHF isn't going to bother anyone. We each draw our own lines in the sand. While admitting that 45 milliwatts isn't a big problem, it's far enough out of spec that I can't honestly pass this radio.

Many thanks to Mike VE7YEG for the use of his radio for testing.

~Reg Natarajan VA7ZEB / HJ1ZEB, July 13, 2024

Discuss this radio on our forums. https://forums.advancedamateur.ca/t/baofeng-uv-21