BaoFeng HTs and Spurious Emissons

The January edition of QST has some disturbing data about dirty transmitters in BaoFeng HTs.

Amateurs are responsible for their transmitters being clean, but most of us don’t have the test equipment to check that. Also, manufacturers must meet the FCC regulations for every transmitter sold.

The ARRL Lab set up at hamfests and tested the HTs that hams had with them. Over four years, only 5% to 9% of BaoFeng HTs passed the test. Alinco, Icom, Kenwood, and Yaesu had 100% pass rates. Wouxon improved from 83% to 100% over the years.

QST 2020 01 HT Testing

From “Technical Correspondence”, QST, January 2020, pages 60-62. This chart is on page 61. QST is available online to ARRL members. This is a link to the article online.

The FCC rules for spurious emissions are in 47 CFR § 97.307 – Emission standards.

What if you already own a BaoFeng, like me?

Run low power. This will reduce the amount of power in the spurious emissions. Reducing the power from 5 W to 0.5 W should reduce the spurious emissions by 10 dB. The spurs still won’t be 40 dB below the carrier, but they will be lower in terms of absolute power. It can’t hurt. It will make your battery last longer, too.

What if you want an inexpensive HT?

Instead of a $50 BaoFeng, save up a bit more for a $75 Yaesu FT-4XR. From my research, this is the only HT under $100 from a major radioo vendor.

The FT-4XR uses the same chipset as the BaoFeng, so it has roughly the same feature set. But it has a clean transmitter and better interference rejection in the receiver. It also has ham-specific firmware, like automatic repeater offsets. That should make it easier to use.

The FT-4XR also uses the same antenna connector as BaoFeng, so aftermarket Nagoya antennas might fit. I would probably try the Nagoya NA-771 for $17, which might fit. I’ve heard recommendations for the Diamond SRJ77CA ($27).

I linked to DX Engineering’s page above, but the FT-4XR is available at similar prices from Ham Radio Outlet, Gigaparts, and other ham stores. Amazon has it at a higher price ($83), oddly.

BaoFeng UV 5R Yaesu FT 4XE

How did this happen?

It appears that the BaoFeng radios were designed for the much more lenient Part 90 emission regulations and do not meet the amateur radio regulations.

An article by AD5GG compares BaoFeng UV-5R emissions to Part 90 (private land mobile) and Part 97 (amateur) regulations. The BaoFeng meets the weaker Part 90 limits, where spurious emissions are not to exceed -20 dBc (dBc is relative to carrier). Part 97 limits spurious emissions to -40 dBc, 100X lower than the Part 90 limit.

Designing for the Part 97 limits requires additional low-pass filtering on the output. The new parts may only be pennies, but it would require a new board design. Maybe new versions of the BaoFeng HTs will be designed to the stricter standards, but I’ll have to see proof of that. The UV-5R is up to the third generation, at least, and still not compliant.

How to get an Amateur Radio License

What are the steps for getting your first amateur radio license?

Start by taking an online test for the Technician license. It is easy and free. You will probably do better than you expect. After the test, note the areas that you need to study. hamexam.org is my favorite online test site. You only need a C (75% correct) to pass.

K6WRU license blur

Now that you know what to study, get a study buddy, get some study materials, or best, both. The No Nonsense Technician-Class License Study Guide by Dan Romanchik (KB6NU) is free as a PDF and is exactly what it says. Study the sections where you are having trouble and keep taking practice tests until you are happy with your scores. Download it from the KB6NU study guide page.

Take a break from your studying to find a license test session. That will give you a deadline. Use the ARRL license exam session search to find a session.

There might be a fee for the exam, up to $15. You can take tests for all of the license levels at one session, so go ahead and take the test for General. You might pass!

After that, find a mentor to help you get on the air. In amateur radio, we call these people an “Elmer”. Use the ARRL club search page to find one near you. On the Web, try the Amateur Radio Elmers Facebook group.

Choosing a radio? That is a different post.

Troop 4014’s First Hike

I learned a new park today, thanks to the girls in Troop 4014. We had a lovely hike at Edgewood Park in Redwood City. I’d never been there, but I’ll be back.

Trail in Edgewood Park

The Scouts chose the route, did all of the map reading and direction finding, and got us back to the trailhead without any fuss. I carried a map, but only looked at it once.

Finding the route

We saw lots of wildflowers, a darkling beetle (one inch long), and three western fence lizards.

Edgewood park western fence lizard

Here is our track. It was 2.14 miles with an elevation gain of 435 feet. It was a nature hike with lots of stops, so we weren’t trying to eat up the miles.

Edgewood Park GPS track

See you on the trail!

Getting Started with Troop 4014

Starting a troop from scratch is a completely different experience from stepping into a functioning troop as Scoutmaster.

Founder strip

We’ve had our third meeting in four weeks. We are using the First Aid track of the BSA meeting plans for new troops. At the first meeting, I showed the girls the initial meeting plans from the Hiking and First Aid tracks and asked them to choose.

Right now, meeting planning is more Den Leader style but breaking in to pairs for them to teach each other from the handbook or other materials.

At the second meeting I brought some parachute cord for knot tying. We cut it into lengths, then I set up a camp stove to fuse the ends, with a cup of water to cool them off. They spent over a half hour melting rope and getting it just right. Big fun.

4014 is not chartered yet. We have a commitment from the charter org and we are linked with Troop 14. We had four 11 year old girls on Tuesday. We have a line on one more, plus two 5th graders who are interested. They’ll “age in” at the end of the school year, but I’ll probably invite them as guests. We have a guest female ASM/mom from another troop and two moms who we can probably sign up.

The Scout rank is a lot harder than the old Scout badge used to be. It used to be a one-meeting badge.

I’m astonished that whipping the ends of a rope is required. I’ll have to go buy some laid rope and whipping twine. Didn’t climbers start using kernmantle rope in the 1960s? Wow.

Scout Me In Neckerchief

My “Scout Me In” neckerchief arrived! I ordered one to show I’m supporting girls in Scouting and to have something to wear while we are getting Troop 4014 ready to charter.

Scout Me In necker

These were originally a restricted item, but now anyone can buy one. It isn’t in the online catalog, so you get it from the national Scout Shop by calling national supply and ordering on the phone (1-800-323-0736).

They quoted a 4-6 week lead time, but mine took about two weeks. It is a pretty fancy necker with a lot of sewing, so it isn’t cheap. With shipping, it was $40.86. I like it.

I’m an Amazon Influencer!

My most popular blog post has 7408 views in the 3+ years since I posted it. It mentions three things and I just saw those three things listed on Amazon under “Frequently bought together” when I visted the page for one of them.

Frequently bought together

These are not especially similar items and there are plenty of alternatives for each one. So these three together mean that Amazon is mining very, very deep into the long tail for similar items. 7408 page views might only mean 74 purchases. Or 15 purchases.

The original post is Better Yamaha CM500 Audio with PTT on Elecraft KX3. A clumsy title, yes, but it is descriptive. I wrote the post because I was tired of replying with the same information over and over again on mailing lists. Now, either on lists or Facebook, I link to the post.

What are the items?

  • A hand-held pushbutton, for turning on the transmitter (“push to talk” switch). This is the page I visited to see the “Frequently bought together” list.
  • A stereo to mono splitter cable. There are hundreds of these, all pretty much the same, but Amazon is showing the exact one I mentioned in my blog post.
  • The Yamaha CM500 headset, an affordable, popular headset for amateur radio use. There are lots of other choices cheaper and more expensive, so this is also a strong hint.

Mostly, there is no reason in the world to associate a hand-held pushbutton switch with these other two items. There are plenty of other hand switches, many of them pre-wired. There are many, many stereo to mono splitters.

Hint for savvy shoppers, the Hosa splitter was $6 when I wrote the article. It is $5 now.