Baofeng BaoFeng Spectral Purity IMD Testing

[NearFieldOperator]

BaoFeng radios are well known to be lacking in front end filtering which results in high spurious harmonics that often fail FCC 97.307e standards. While they are popular for being extremely inexpensive to comparative models, they are often ridiculed as piles of junk and any respectable ham operator would find little use for them.

As an RF Engineer, I wanted to see how bad it really was failing instead of just taking the internet’s word for it. I have held a Technician license for 10 years and have recently convinced a few friends to get into ham radio. They all bought UV-5R radios from the “BAOFENG Store” on Amazon.com spanning from Fall of 2022 to Summer of 2023. I decided to test them on a Keysight PXA Spectrum Analyzer in my lab. This would also allow us to measure to overall output power and see if they are reaching the marketed 5 watts. I also had a BF-F8HP on hand that I could test.

To quote a portion of the test standard:

“For a transmitter having a mean power of 25 W or less, the mean power of any spurious emission supplied to the antenna transmission line must not exceed 25 µW (-16dBm) and must be at least 40 dB below the mean power of the fundamental emission...”

So the threshold for any spurious signal is -16dBm. I’m not sure how they determined that level of power was acceptable for spurious emissions, but that’s what we will be focusing on.

For the 5W radios, I included a 10dB attenuator to lower the signal enough to not damage the spectrum analyzer. The 8W radio also included an additional 3dB attenuator for additional protection. The attenuator(s) and cable loss to the analyzer were calibrated with a signal generator and the following results are showing the power levels at each radio’s antenna port in dBm. Test frequency was the 2m NCF (146.52 MHz).

Spectrum Testing Results

It was surprising to see that the only radios to fail were older ones bought over 4 years ago. None of the new radios failed and had at least 15dB of margin to the spurious threshold. Some had a 4th harmonic present and that may be due to ordering from a different supplier on the BAOFENG Store on Amazon. While this was a limited pool of radios, the trend is very telling that BaoFeng is taking EMC more seriously.

Main takeaways:

1. Recent BaoFeng UV-5R radios have upgraded front end filtering that is FCC 97.307e compliant.

2. The BF-F8HP having “better filtering” was not necessarily true 4 years ago. I cannot speak to the design now, but the current UV-5R design is more than adequate.

3. Average transmit power for current radios averages 4.5W on the 2m band.

I cannot speak to the overall quality of these radios in terms of sensitivity, front end loading, frequency precision, etc. especially compared to their competition. I have seen Kenwood HTs spectral purity tested that show all harmonic bands below -70dBm. I don’t doubt that the 3 main brands have better quality radios and if I were to design my own I would take a different approach than BaoFeng, but their performance-to-cost ratio is very high. There is no surprise why these radios are so popular for hams just getting started.

If anyone is considering one of these as a first-time handheld I would not hesitate to recommend them. And if anyone has the capability to measure their own models I would be interested to see if this trend of compliant radios is becoming the norm.

Spectrum Plot Results:
Radio Test
UV-5R Radio1
BF-F8HP Radio
UV-5R Radio2
UV-5R Radio3
UV-5R Radio4
UV-5R Radio5
UV-5R Radio6
UV-5R Radio7

 

[AK9R]

It was surprising to see that the only radios to fail were older ones bought over 4 years ago.

In 2017-2019, I went around to hamfests with a Rigol DSA815 spectrum analyzer and associated attenuators, cables, adapters and offered to test handheld radios for spurious emissions using equipment and methods similar to what the ARRL was doing at hamfests at the time. In my experience, the older the Baofeng, the worse it was when it came to spurious emissions. I particularly recall a UV-82 that showed its first spur at approximately 73 MHz and every multiple up to 1 GHz while transmitting on 146.52 MHz.

 

[kayn1n32008]

From numerous conversations, most hams don't give a **** about what's coming out of the antenna, they want the cheapest piece of **** radio, for the least amount of money.

They have no clue about spectral purity, and care even less.

It's all about their ****ty $20 radio and 'how great it is' because if they actually, maybe one day, go on a hike, or go for a paddle in their supposed canoe, they might drop that 'expensive big 3 brand radio' and it might break or sink. But their **** Chinese radio is only $20 so they will go but 10 of them so they have a fresh supply of **** radios that sound like **** and are barely functional. But hey. It's a ****ty cheap ass radio that 'works greeeaaaatttttt'

 

[MTS2000des]

Bowelturds are lowest common denominator radios based on low cost consumer grade SOCs that were designed by their maker (RDA) to be used in toy walkie talkies, bubble pack throwaway radios, and other low rent junk intended for casual consumer use. As such, even with front end filtering, and tx output filtering to remove the blades of grass, these chipsets lack performance amateurs expect such as useful band scan with fast scan rates, reliable CTCSS/DCS decoding without unmute failures, solid transmit audio that isn't muddy and muffled, and nevermind their glitchy and irritating firmware that makes programming and operating them in the field (VFO operation/keypad programming) a hassle for new and old hams.

A 25 year old Yaesu FT-50 that can be had for around a hundred bucks fully equipped mops the floor with these turds.

 

[G7RUX]

RF engineer here too.
All received and a nice bit of testing although what you have measured is the direct spurious emissions from the transmitter. Baofengs and similar sets have never been stellar in this regards but they are clearly just about OK.
However, I would suggest looking at the intermodulation distortion the transmitter generates when presented with reasonably strong in-band signals from other transmitters in the vic since this is the main problem with the very crude designs used in these sets.
I made measurements of Tx IMD during 2020 on a selection of radios, including handhelds, mobiles and base units and whilst few handhelds performed particularly well the Baofengs and similar were quite horrible, with very large IMD products all over the place, including squarely within VHF airband and low, mid and high-band VHF PMR. They were a little better in UHF but not by much.
I cannot post my report on these I’m afraid as it was done for my employer.

 

[JustinWHT]

Good job! 👍

I have a two year old Gen 3 UV-5R and a UV5RM from two months ago.

Side note: I see lots of Uv-5R radios advertised as Gen 3, but show a Band selection button below the speaker to the right. Version history says this was eliminated starting with Gen 2.

I suspect there are lot of dealers that don't want to be stuck with inferior Gen 1 radios and claiming they are Gen 3.

 

[dlwtrunked]

From numerous conversations, most hams don't give a **** about what's coming out of the antenna, they want the cheapest piece of **** radio, for the least amount of money.

They have no clue about spectral purity, and care even less.

It's all about their ****ty $20 radio and 'how great it is' because if they actually, maybe one day, go on a hike, or go for a paddle in their supposed canoe, they might drop that 'expensive big 3 brand radio' and it might break or sink. But their **** Chinese radio is only $20 so they will go but 10 of them so they have a fresh supply of **** radios that sound like **** and are barely functional. But hey. It's a ****ty cheap ass radio that 'works greeeaaaatttttt'

Test evidence with current radios?

 

[prcguy]

With a 5w radio and 10dB attenuator you are hitting the analyzer with 27dBm or 500mW and just 3dB under the PXAs maximum 30dBm input rating for damage. You don’t want to run meaningful tests at that level as the instrument can generate its own IMD at high input levels.

Did you do any testing to ensure any measured radio harmonics are real, like make a few 1dB attenuator changes to see if the displayed harmonic levels stay the same or decreases by 2dB indicating it’s IMD is generated within the instrument?

 

[G7RUX]

In general for harmonic distortion and IMD testing of this sort you will want some method of filtering/rejecting the fundamental output frequencies sufficiently that your analyser has enough dynamic range to reliably indicate the (hopefully small) unwanted products. Using a straightforward attenuator will obviously reduce both the fundamental(s in an output intermod test) and the products you want to measure, dramatically reducing the dynamic range your measuremenT system has.

Having personally carried out these measurements dozens of times, including on a range of amateur transceivers, I can confirm that earlier Baofengs were terrible in both harmonic and intermodulation distortion but more recent units are much better with harmonic distortion although they are still not very good with IMD.

 

[dlwtrunked]

BaoFeng radios are well known to be lacking in front end filtering which results in high spurious harmonics that often fail FCC 97.307e standards. While they are popular for being extremely inexpensive to comparative models, they are often ridiculed as piles of junk and any respectable ham operator would find little use for them.

As an RF Engineer, I wanted to see how bad it really was failing instead of just taking the internet’s word for it. I have held a Technician license for 10 years and have recently convinced a few friends to get into ham radio. They all bought UV-5R radios from the “BAOFENG Store” on Amazon.com spanning from Fall of 2022 to Summer of 2023. I decided to test them on a Keysight PXA Spectrum Analyzer in my lab. This would also allow us to measure to overall output power and see if they are reaching the marketed 5 watts. I also had a BF-F8HP on hand that I could test.

To quote a portion of the test standard:

“For a transmitter having a mean power of 25 W or less, the mean power of any spurious emission supplied to the antenna transmission line must not exceed 25 µW (-16dBm) and must be at least 40 dB below the mean power of the fundamental emission...”

So the threshold for any spurious signal is -16dBm. I’m not sure how they determined that level of power was acceptable for spurious emissions, but that’s what we will be focusing on.

For the 5W radios, I included a 10dB attenuator to lower the signal enough to not damage the spectrum analyzer. The 8W radio also included an additional 3dB attenuator for additional protection. The attenuator(s) and cable loss to the analyzer were calibrated with a signal generator and the following results are showing the power levels at each radio’s antenna port in dBm. Test frequency was the 2m NCF (146.52 MHz).

Spectrum Testing Results

It was surprising to see that the only radios to fail were older ones bought over 4 years ago. None of the new radios failed and had at least 15dB of margin to the spurious threshold. Some had a 4th harmonic present and that may be due to ordering from a different supplier on the BAOFENG Store on Amazon. While this was a limited pool of radios, the trend is very telling that BaoFeng is taking EMC more seriously.

Main takeaways:

1. Recent BaoFeng UV-5R radios have upgraded front end filtering that is FCC 97.307e compliant.

2. The BF-F8HP having “better filtering” was not necessarily true 4 years ago. I cannot speak to the design now, but the current UV-5R design is more than adequate.

3. Average transmit power for current radios averages 4.5W on the 2m band.

I cannot speak to the overall quality of these radios in terms of sensitivity, front end loading, frequency precision, etc. especially compared to their competition. I have seen Kenwood HTs spectral purity tested that show all harmonic bands below -70dBm. I don’t doubt that the 3 main brands have better quality radios and if I were to design my own I would take a different approach than BaoFeng, but their performance-to-cost ratio is very high. There is no surprise why these radios are so popular for hams just getting started.

If anyone is considering one of these as a first-time handheld I would not hesitate to recommend them. And if anyone has the capability to measure their own models I would be interested to see if this trend of compliant radios is becoming the norm.

Spectrum Plot Results:
Radio Test
UV-5R Radio1
BF-F8HP Radio
UV-5R Radio2
UV-5R Radio3
UV-5R Radio4
UV-5R Radio5
UV-5R Radio6
UV-5R Radio7

Good to see your post. I have been telling many that they are quoting outdated issues about older Baofengs but it is hard to change habits and I am sure that will continue.

 

[kayn1n32008]

Good to see your post. I have been telling many that they are quoting outdated issues about older Baofengs but it is hard to change habits and I am sure that will continue.

Even if they are cleaner transmitters, they are still garbage radios. It won't change my opinion of them

 

[merlin]

For the poor quality of parts that go into all the Baofengs, you will run into a wide range of spectral purity and receive specs.
Some, so bad they are worthless, others acceptable but not pass any FCC testing. some others would just come in under the wire.
I ran my only UV-5R through the bench and I lucked out with one that would pass. ( not found in my bugout bag though.)
Never heard of Gen x, if it is UV-5R it has the very same board within this model, made at the same factory with the same parts.
You can actually find a cheaper CCR. better QC that will compare with the Yaesu FT-60, more features and at the bench, better than Baofeng.

My 3 pocket radios:

 

[redbeard]

Even if they are cleaner transmitters, they are still garbage radios. It won't change my opinion of them

Right, 1 less complaint on a long list of complaints is still a long list! Garbage!

 

[dlwtrunked]

Right, 1 less complaint on a long list of complaints is still a long list! Garbage!

Then list them so we can see if we agree (seriously, not meant to be argumentative).

 

[redbeard]

Then list them so we can see if we agree (seriously, not meant to be argumentative).

They've been exhaustively listed for years on this very site and others. I don't care to rehash them all, nor do I need to. Anyone with a brain not clouded by cheapness can see the quality. I also don't care if you agree or not. (nothing personal)

We are surrounded by garbage products in every facet of life and anyone who enjoys cheap crap is fooling themselves for the love of money. Like people who buy things only to say they own $THING and slap themselves on the back for saving so much money doing so. People that like to go on shopping sprees to satisfy their consumerism brainwashing but can't afford anywhere but FIVE BELOW.

Perhaps we should allow Chevy Spark into NASCAR, you know, to bring more people into the hobby. Let's throw out all the rules too because safety costs money.

Some of the issues aren't even technical. The FCC gatekeeps the various radio services to certain levels to try and keep things under control. These have shattered all of that and now we find jammers and willful interference driving places like NYC to encryption and Pittsburgh to trunking. Volunteer fireman using them for life safety, both their own and the public's. Preppers who think it's God's gift to commo.

I hate them for their bottom of the barrel specifications and QC, in line with the cheapest of children's toys, and I hate them for what they've done to our society. People complain that Lindsay has ruined the hobby of scanning with online streaming, but God Forbid we slander the beloved UV-5r and what its done.

All hail King Baofeng, first of his name, breaker of rules, Lord of the roger beep, Messiah of simps, and bane of the seven continents.

 

[mmckenna]

All hail King Baofeng, first of his name, breaker of rules, Lord of the roger beep, Messiah of simps, and bane of the seven continents.

The low price has put tools in the hands of those that have neither the knowledge nor integrity to use them responsibly.

 

[JustinWHT]

have a two year old Gen 3 UV-5R and a UV5RM from two months ago.

After watching hours of YouTube vids testing spectrum purity of Baofeng radios, all generations of UV-5R, BF-F8HP, and 5RM radios, I cannot in good conscience continue to use them. I don't want to donate them as that defeats the purpose of preventing spurious interference, I'll give them to a friend that literally lives in middle of nowhere - 30 miles to nearest Walmart - and he can use them in FRS with causing it interference, albeit not legally.

An better radio would be the Baofeng GT-5R which appears to pass spurious emissions compliance. Of course even more better would be another Yaesu.

 

[a727469]

I must say that this thread has become a rather extreme forum for opinions..mine is simple..I can not control the use or perceived quality of radios, I would love to buy an American handheld or other(most not available), I wish the world were different(but it isn’t), my purchase of a single radio is my choice in a free United States(thank goodness). I will purchase all radios that most fit my needs and are the most fun and therefore I own radios from Uniden, Icom, Yaesu, Alinco and Baofeng. Some better, some worse, but all fun or I would sell or throw away.

 

[a727469]

One more thing, to make clear, all my radios Baofeng or others have been bought through dealers in this country hopefully helping keep their jobs etc. Yes, there are too many imports and frankly communist china is horrible but not buying some of them ultimately hurts our own people. Not just radios but many products.
Concerning the technical side, I have owned some radios(a few Yaesu‘s for example) that were horrible, defective, dirty signals and distortion and should never have been released. I will say those radios came out quite a few years ago before youtube etc but Baofeng is not alone. Again, we have and should have a choice as to what we buy and as long as the product meets whatever laws we have, it is up to the individual as stated previously by many to research and choose accordingly. I, too have chosen to buy or not buy products after watching youtube 📺📺!

Back to playing with radios!📻📻📻

 

[JustinWHT]

he can use them in FRS with causing it interference, albeit not legally.

Correction:
he can use them withOUT causing interference