[Sjef Verhoeven] still loves radio and enjoys the challenge of listening to radio signals from far away. He wanted to build his own radio and turned to the TEF6686 chip, a device often found in car radios. It is known to be very sensitive and seemed perfect for pulling in weak signals. So [Sjef] built this DIY radio and shares the details in this recent Spectrum post.
Unlike older radio-on-chip devices, the TEF6686 is a DSP, which, according to the post, is part of the reason it is ultrasensitive. Even though it is made for car radios, the device is versatile and can pick up shortwave as well as the usual broadcast bands, with the right configuration.
Initially, [Sjef] wanted to design his own tuner but rapidly found inexpensive modules. These had shielding and through-hole pins, making it much easier to deploy a radio using the chip. The modules run around $25 or less.
The rest of the project centers around an ESP32 and an OLED display, along with switches and encoders. The device requires a host to upload its firmware, so a device with a lot of flash memory was a must. The host must also store fonts for the OLED, and [Sjef] even included a database of ham radio callsigns so that when receiving a North American station, you can instantly see which state or province the station is probably in.
If you want to build a duplicate of this radio, all the details are on GitHub. You can also find kit versions.
If you want to build your own shortwave radio, you could spend more. Or, break out a breadboard, if you prefer.
FYI, The chip is less than $9 at Digi-Key
https://www.digikey.com/en/products/filter/rf-receivers/870?s=N4IgjCBcoLQdIDGUBmBDANgZwKYBoQB7KAbRAFYA2ADhAF0BfAmAJilGUgBcAnAV3xFSFegzFA
Or free if you have an older car and you don’t mind missing the radio. Or you are near a u-pull junkyard and scrounged radio is cheap.
Older car? The chip came out in 2013.
That’s 9 years newer than my car!
B^)
So many people just keep buying new cars every few years… rolling their debt into the next one… it’s sick. They all want to look rich but the rich person is often the one driving the humble car because they get that way by knowing how to use their money wisely.
Agreed. (happily driving a 2010 model car)
Hear, hear! I’m only driving a 2012 now because my 2006 got totaled (ca. 2018).
Module is easier. Those are QFN packaged ships with the center pad.
The modules on Aliexpress are about $8-9 if you search for TEF6686
RF is a lot more finicky than the slow speed binary switching in a typical ‘duino project. I bet a lot of us would rather spend a few more dollars on a well designed PCB module than roll that part from scratch.
OTOH… if said module is little more than a breakout board with little regard given to RF… then that’s not good. I have a couple cheap Si Labs chip modules that look to me like that’s all they are. I don’t know if it’s worth my time to build them into something or not.
QFN is the worst.
I’d be interested in a shootout between this and a good Pioneer just on FM. City and DX. Intermod and overload are bigger problems than selectivity with such one chip wonders.
If you are going to compare it to the MVH-S110 / S120 / S220 series, then the performance will be pretty much identical.
The ILI9341 is a LCD-TFT driver, not OLED.
Well it may cover “shortwave” but only AM is supported. I might be ordering parts if it did SSB.
The Qodosen dx-286 uses the tef6686, if you really don’t want to make a radio yourself.