In amateur radio circles, almost no single piece of equipment serves as more of a magnet for controversy than the humble Baofeng handheld transceiver. It’s understandable — the radio is a shining example of value engineering, with just enough parts to its job while staying just on the edge of FCC rules. And at about $25 a pop, the radios are cheap enough that experimentation is practically a requirement of ownership.
But stripped down as the Baofeng may be, it holds secrets inside that are even more tempting to play with than the radio itself. And who better than [HB9BLA], a guy who has a suspiciously familiar Swiss accent, to guide us through the RF module at the heart of the Baofeng, the SA818. For about $8 you can get one of these little marvels off AliExpress and have nearly all the important parts of a VHF or UHF radio — an SDR transceiver, a power amp, and all the glue logic to make it work.
In the video below, [Andreas] puts the SA818 module through its paces with the help of a board that pairs the module with a few accessories, like an audio amp and a low-pass RF filter. With a Raspberry Pi and a Python library to control the module, it’s a decent imitation of the functionality of a Baofeng. But that’s only the beginning. By adding a USB sound card to the Pi, the setup was able to get into every ham’s favorite packet radio system, APRS. There are a ton of other applications for the SA818 modules, some of which [Andreas] mentions at the end of the video. Pocket-sized repeaters, a ridiculously small EchoLink hotspot, and even an AllStar node in an Altoids tin.
Of course, if you want to get in on the fun, you’re going to need an amateur radio license. Don’t worry, it’s easy — we’ll help you get there.
I used hamradiotestDOTcom and got 100% on my Extra 9 years ago – the only test I ever aced for ham radio. I’m not a shill, but I enjoyed their teaching algorithm so much, I wanted to share it.
I did the same.
Isn’t that pointless? You can already connect any baofeng to a PC with a suitable cable and sound card and use APRS. Why would you destroy a radio that’s trying to redo what it’s already doing?
This seems like a lower barrier for entry. Do you have any suggestions on where to start with APRS?
http://greatfractal.com/PacketRadio.html
73
Great stuff, thanks!
https://www.k0pir.us/aprs-basics-for-beginners/
Many thanks
Basically, all you need to start and contribute to the map is a 2-meter scanner, a sound card, and a small computer with the right software and Internet connection.
You’re not destroying a radio – you’re using the chip at the heart of a Baofeng, built into the SA818 ‘chip’ and going from there.
That huge SA818 would never fit inside the Baofeng radio, and didn’t you notice the lack of chip removal steps in the examples?
Ah sorry I didn’t watch the video before commenting :D English is not my native language, I guess I misunderstood… But still I think it’s pointless just buy a baofeng and connect a sound card :D if the module could work with hf it would be different but only vhf/uhf not worth all the effort.
It isn’t about “getting to APRS’…it is about learning about SDRs in a very inexpensive way, and applying that learning to something interesting. It is okay if the project isn’t interesting to you. In my 40 years in amateur radio, and 40 years of various radio telecommunications industries, I have learned that different people have differing interests. Some like to build, some like to operate…and that is okay…we need both types.
Well said Derek – It’s been a long time.
Experimenting is a major pet of amateur radio for many of us. You can also buy a very nice transceiver for not that much money, or build your own from scratch with discrete components. In abstraction ham radio is actually pretty dumb. Why do anything? Straining for noise in the static when I can take my supercomputer out of my pocket and comment on a HaD article then call my friend in Europe without even standing up.
Tongue-in-cheek question I suspect, but for some of us the sense of wonder is still there. That hand held computer/phone is the long term result of hams experimenting since 1895.
You never seen what ham radio can do today, with or without noise mumble. Ham radio operator can be outdated, lost in time but ham radio allways have something new to offer.
Ater flooding, earthquake, war, only radio stations work. Because your supercomputer in pocket is dead without all base stations around.
Ham radio is not only one way of communication. It is learning and understanding how things work, research about tech.
True, but the idea is to see what all you can fo by gorching around the inside of the unit; that’s the ham/hacker spirit.
Who said anything about “destroying a radio”? Did you even watch the video first? Those modules have been available on eBay for AGES.
They’ll fit many places a full blown radio will not. A PC with a sound card isn’t exactly portable, and not embeddable in small spaces.
Yeah i watched video later, lets skip that destroying part. Still I think it’s pointless just buy a baofeng or any kind cheap radio and connect what ever you want a desktop or laptop PC, raspberry pi, other SoC etc. It will be more portable than this thing with its guts left out.
Some say it’s about experimentation and the spirit of radio, but I don’t think it has much to do with experimentation, taking an already existing module and connecting it to something that can make a sound. If you’re looking for experimentation, I recommend you take a look at the USDx project. If the module could work with hf it would be different but only vhf/uhf not worth all the effort.
Audio interfaces alone are pure suck. You can’t rely on VOX operation cleanly all the time, because you don’t always get the best audio out. Using modules like these expose additional pins like a carrier-operated receive/squelch pin, which will go high when the squelch opens on the radio (so you can capture the incoming signal, no matter how faint).
On top of that, these modules let you control the radio itself, something a pure audio-only interface can’t do. Changing frequencies can be done in software, not a hand having to smack buttons.
COR/COS is a huge deal in audio interfaces. While, yes, you can mod a Baofeng to grab COR out for your interface, a module like this means all the “guesswork” is gone. Give it power, signaling, and computer control and you’re off to the races.
Probably worth noting that pretty much anything you buy at this point under the ‘Baofeng’ name is a knockoff (the company rebranded as ‘BTech’ about a decade ago due to inability to control the knockoffs), so what you get may vary (in some cases, substantially).
Uhm, no.
There’s Baofeng, BTech, and Baofengtech.
Baofengtech sell both Baofeng and BTech branded radios – I don’t believe they would carry ‘knock-offs’ of Baofeng radios.
It seems like the BTech radios are packaged for the US market, and Baofeng radios are packed for the world market.
There’s a lot of information floating around about Baofeng radios – remember when everyone was saying they were built with rejected cellphone chips – that was how they could make them so cheap?
Needs 1kW linear. Off to aliexpress we go!
This is FM, class C would suffice.
Ironic isn’t it. You need a licence to talk on amateur radio, yet Joe Rogan can broadcast to millions without any licence at all.
The stations that air his programming all have to have licenses.
Not ironic in the least. Content, from Joe Rogan or anyone, has NOTHING to do with licensing. Licensing pertains to the use of the radio frequency spectrum and the proper use of the hardware to do so, as Joe’s comment of November 15 accurately acknowledges.
Does anybody know what PA amplifier chip is in this module?
The final amp in the one I tore apart was a SOT-89-packaged MOSFET from Toshiba. I don’t have it in front of me to check, but 2SK3074, maybe?
These little transceiver modules come in various flavors, there is even a DMR radio version with an AMBE voice codec (P/N DMR828-AMBE-U). LCSC distributes the modules.[1] G-NiceRF makes them.[2] These modules are notoriously bad in Chinese radios made by the likes of Baofeng because the manufacturer refuses to include adequate RF filtering. Plus a wider AGC range would help too. But by applying some common sense you can easily design and build a usable and legal transceiver for use on the U.S. amateur radio bands.
1. G-NiceRF Transceiver Modules @ LCSC
https://lcsc.com/products/Modules_959.html?brand=13314
2. G-NiceRF Home
https://www.nicerf.com/
My two brand new Baofeng UV-82 shipped in non-workable condition (VFO totally crippled) even after reset frequency on display does not match workable frequency and are plain deaf nothing is picked up in RX ! One station can not hear the other and reverse.
Baofeng is selling crap ! There is a reason why other brands are more expensive also reliable ones too !