I thought I was about to do a normal HT write-up: bigger screen, USB-C charging, a couple quality-of-life tweaks, and a quick compare to the classic UV-5R. Then I watched a clip that made me put the “features” stuff on pause. If the radio is spraying harmonics, none of the nice-to-haves matter. This is a practical look at one UV5R Mini sample, how it was tested with an SDR tap into a dummy load, and what “dirty” really means for day-to-day ham use.
📌 TL;DR — One sample, one big red flag
- Core idea: A UV-5R Mini unit showed a strong 5th harmonic in a simple SDR tap test.
- Why it matters: Harmonics can cause interference, and failing suppression targets can put you on the wrong side of compliance.
- Key benefit: The test setup avoids the usual “tiny analyzer” arguments and focuses on relative levels.
- Who it’s for: Anyone using cheap handhelds on VHF/UHF who wants more than “it works” as a standard.
The Baofeng UV-5R Mini looks like Baofeng took the old idea and modernized it: a larger display that’s easier to read, a nicer PTT feel, and USB-C charging so you’re not hunting for a weird cable. You can even hit and hold “0” to pull up the weather channels. On paper, it’s the kind of update people have been asking for.
But “dirty” radios don’t get a pass because they’re convenient. When hams say a handheld is dirty, they usually mean the harmonic output and other spurious emissions are too high. That can be a problem even if you’re only chatting on a local repeater. It’s also why you’ll see a lot of heat online when different people test the same model and get different results.
What “dirty” means in plain ham terms
When you transmit on, say, 146.520 MHz, you want most of your energy right there on the fundamental frequency. Harmonics are multiples of that frequency (2x, 3x, 4x, 5x). A clean transmitter suppresses those harmonics strongly. A dirty one lets too much through. For VHF/UHF gear, a common benchmark you’ll hear is about 40 dB down from the carrier (the exact requirement depends on service and measurement method, but 40 dB is the number people quote for a reason). If you’re only 30-something dB down, that’s not “meh,” that’s “pay attention.”
The quick math from this test
| Metric |
Value |
Why It Matters |
| Fundamental level (tap reading) |
About 2.1 dBm |
This is the reference point for comparing harmonic suppression. |
| 5th harmonic difference |
32 dB down |
That’s short of the commonly expected ~40 dB suppression target. |
How the test was done (without the usual drama)
The goal was to remove variables and focus on relative levels. Instead of a pocket analyzer and mystery attenuation, the radio was terminated into a dummy load and sampled with an RF tap. The tap fed an SDR, which makes it easy to look at the fundamental and harmonics as separate measurements with the same setup.
- Step 1: Connect the UV5R Mini to a dummy load through a tuner that’s been modified with an RF sampler.
- Step 2: Feed the sampler output into an SDRplay RSP1A and view it in SDR Uno.
- Step 3: Measure the fundamental, then tune to the 5th harmonic frequency and measure again using the same tap path.
Why results vary between testers
If you’ve been following the chatter, you’ve probably seen people argue because one person gets a clean-ish plot and another person sees a harmonic spike. The boring answer is the most likely one: batch variation. Radios are built in runs, parts come from different lots, and QC on a $20 handheld is not going to look like QC on a commercial-grade unit.
- One batch might have a slightly different low-pass filter component value.
- One lot of parts might drift more at VHF/UHF than another.
- A unit that “passes” at one power setting might look worse at another.
What these numbers do (and don’t) prove
This is not a certified lab test. It’s a reality check. A tap-and-SDR approach is great for comparison and spotting “whoa, that’s loud” harmonics. It’s not the same as a calibrated spectrum analyzer measurement with documented uncertainty, absolute power, and a formal test procedure.
That said, seeing a 5th harmonic only 32 dB down is enough to stop and think. If you’re curious about cleaning up your station in general, check out our SDR section and Radio articles for more testing and troubleshooting ideas.
Practical tips if you own one
If you already bought the UV5R Mini (or you’re thinking about it), here’s how to be a good neighbor on the bands without turning it into a whole thing.
- If you can, test your own unit. An SDR and a safe tap into a dummy load will tell you a lot.
- Use the lowest power that reliably works. More power can mean more harmonic energy, depending on the design.
- Be smart about where you transmit. If you’re near sensitive services, or you’re in a dense RF area, “probably fine” isn’t a great plan.
So, is the UV5R Mini dirty?
Based on this one sample and this test method, it sure looks that way. The 5th harmonic came in about 32 dB below the fundamental on the SDR tap, which is not where you want to be if you’re aiming for clean suppression.
- Nice features (USB-C, bigger screen) don’t offset RF cleanliness concerns.
- Batch variation is a real possibility, which is why your results might differ.
- A proper spectrum analyzer follow-up is the right next step for a definitive answer.
If you’ve tested your Baofeng UV-5R Mini, drop your results in the comments on the video above and tell us what you saw.