Most classic tuner design parts are unobtainable or eBay only these days.
A couple of possibilities:
1)Take an old tuner as a parts donor and do a new PCB with smd capacitors - most old tuners were badly compromised by single layer PCBs and rubbish RF disc capacitors.
2)Build around a good quality SDR module and a Pi.
A couple of possibilities:
1)Take an old tuner as a parts donor and do a new PCB with smd capacitors - most old tuners were badly compromised by single layer PCBs and rubbish RF disc capacitors.
2)Build around a good quality SDR module and a Pi.
I've had success with the Si4831 from Silicon Labs:
Si4820/24/25/31/35/36 Mechanically-Tuned AM/FM Radio Receivers - Silicon Labs
Other than being an SMD device, it's not difficult to implement. The data sheet and application note are required reading:
https://www.silabs.com/documents/public/data-sheets/Si4831-35-B30.pdf
https://www.silabs.com/documents/public/application-notes/AN555.pdf
Si4820/24/25/31/35/36 Mechanically-Tuned AM/FM Radio Receivers - Silicon Labs
Other than being an SMD device, it's not difficult to implement. The data sheet and application note are required reading:
https://www.silabs.com/documents/public/data-sheets/Si4831-35-B30.pdf
https://www.silabs.com/documents/public/application-notes/AN555.pdf
For both AM and FM, you'll find that a modest investment in an antenna may be one of the best things you can do.
As far as mechanical components -- many of the variable capacitors are readily replaced with tunable diodes -- and rf coils and transformers are not all that difficult to make -- ham radio guys do it all the time.
As far as mechanical components -- many of the variable capacitors are readily replaced with tunable diodes -- and rf coils and transformers are not all that difficult to make -- ham radio guys do it all the time.
Last edited:
The Silab parts are great, I designed one a few years ago, using the Si4735. it was a follow on to an Elektor article DSP radio. A real simple one to put together. The Si4735 part comes in SSOP so easier than DFN for soldering. I added a lot of extra software to the original project and another fellow in Germany wrote some fantastic RDS decoder code for the European market.
Mother loves the radio, she gets RDS display of the song titles.
I saw recently that Elektor has a version using the Raspberry Pi as the compute engine and a SiLab Class "D" amplifier. 2 chip radio, plus the controller of course.
Mother loves the radio, she gets RDS display of the song titles.
I saw recently that Elektor has a version using the Raspberry Pi as the compute engine and a SiLab Class "D" amplifier. 2 chip radio, plus the controller of course.
Attachments
Last edited:
I got a friend with a Heathkit order me the tuner head as a spare part ($15) and did the same. Now I would go SDR, I have an AM/FM/SW Kaito one that sounds quite good (I think it got a rave review by a HAM magazine???).
The Silicon Lab parts look interesting. Their FM sensitivity is poor - 10uV to decode RDS and the large signal handling is suspect, I struggle to interpret the datasheet
There are plenty of low noise gain blocks available these days, you do need a low pass filter at least to reject the VHF mobiles just above 108 MHz or you will get intermodulation.
There are plenty of low noise gain blocks available these days, you do need a low pass filter at least to reject the VHF mobiles just above 108 MHz or you will get intermodulation.
I find the very best, highest sensitivity FM tuners come in pocket radios and cassette players from the 90's.The The circuits with a crystal shown on the schematic. The Lorexx tape player I'm listening to now had a Unisonic UTCLAG668 IC in it.
The diy part comes in replacing the worn out volume pot (impossible to buy) and ditching the cassette player that comes with them that would run the battery down if you pushed the rewind button by accident. Fitting one in a nice case that didn't look like it came from the garbage (where this one was salvaged) would be a nice touch.
The digital synthesis Sony 8RF-377V pocket radio I bought in the two thousands was a PO* compared to the Lorexx. Hissy, poor sensitivity. However digital synthesis is the wave of the future, since high speed digital circuits are cheap.
The diy part comes in replacing the worn out volume pot (impossible to buy) and ditching the cassette player that comes with them that would run the battery down if you pushed the rewind button by accident. Fitting one in a nice case that didn't look like it came from the garbage (where this one was salvaged) would be a nice touch.
The digital synthesis Sony 8RF-377V pocket radio I bought in the two thousands was a PO* compared to the Lorexx. Hissy, poor sensitivity. However digital synthesis is the wave of the future, since high speed digital circuits are cheap.
Last edited:
I had a Pioneer "Super Tuner" from the 1980's -- wish I had pulled out of the Oldsmobile station wagon when I traded in that jalopy. It really was super.
Since you said that you would like to have radio as audio source,I think I can help you in some ways.
Firstly,You need to be specific whether you prefer DX receiving or HiFi receriving? Different radio chips perform differently in sensitivity, selectivity,functionality and the quality of audio.
I prefer the DSP solutions provided by NXP.I have used TEF6635 TEF6638 TEF6686 SAF7741 SAF7751, all of them are controlled by myself.I think it could be a good example for referring.
Firstly,You need to be specific whether you prefer DX receiving or HiFi receriving? Different radio chips perform differently in sensitivity, selectivity,functionality and the quality of audio.
I prefer the DSP solutions provided by NXP.I have used TEF6635 TEF6638 TEF6686 SAF7741 SAF7751, all of them are controlled by myself.I think it could be a good example for referring.
For sensitivity and selectivity,I prefer SAF7751 and TEF6686.
The former one is a single tuner, offers a high end feature set such as Channel Equalizier and Multipath improvement.
SAF7751 is the most advanced receiver ever used in car tuners, this one supports more features such as FM phase diversity which utilizes two antennas at the same time.Further more,thr advanced Imporoved phase diversity algorithem could be used for better performance which requires for firmware update.
You could have a look at my works:
安全检查中...
安全检查中...
Well, I talked in Chinese you could use google translation to know a brief about it.And you can directly send me message if you have interists in these chips.I'm happy to help.
These car tuners are quiet cheap,The SAF7751 tuner is only 45 Chinese Yuan(including the Toll ),which is only about $6.7,this makes these ideal products to use.
The former one is a single tuner, offers a high end feature set such as Channel Equalizier and Multipath improvement.
SAF7751 is the most advanced receiver ever used in car tuners, this one supports more features such as FM phase diversity which utilizes two antennas at the same time.Further more,thr advanced Imporoved phase diversity algorithem could be used for better performance which requires for firmware update.
You could have a look at my works:
安全检查中...
安全检查中...
Well, I talked in Chinese you could use google translation to know a brief about it.And you can directly send me message if you have interists in these chips.I'm happy to help.
These car tuners are quiet cheap,The SAF7751 tuner is only 45 Chinese Yuan(including the Toll ),which is only about $6.7,this makes these ideal products to use.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.