Feel the same. Hard to find....
Which project did you find ?
I found this one , which looks quit interesting. I want to give it a try, and began to draw a PCB, but some details still puzzle me... Tried to e-mail the author, but he's unreachable. Have someone here built this project, or part of ?
Which project did you find ?
I found this one , which looks quit interesting. I want to give it a try, and began to draw a PCB, but some details still puzzle me... Tried to e-mail the author, but he's unreachable. Have someone here built this project, or part of ?
there is a FM Tuner newsgroup on yahoo at:
http://groups.yahoo.com Yahoo is a pain to work with, too cumbersome, too many ads.
there seems to be a lack of willingness to get fingers dirty for most audio DIY'rs with a project like this, but it certainly isn't out of the realm of ham radio types who build 144MHz receivers and tuners all the time. I think that one of the best approaches would be to cannibalize an FM3 with a new front end.
most "off the shelf" multiplexer chips are out of production.
jack
http://groups.yahoo.com Yahoo is a pain to work with, too cumbersome, too many ads.
there seems to be a lack of willingness to get fingers dirty for most audio DIY'rs with a project like this, but it certainly isn't out of the realm of ham radio types who build 144MHz receivers and tuners all the time. I think that one of the best approaches would be to cannibalize an FM3 with a new front end.
most "off the shelf" multiplexer chips are out of production.
jack
RF circuit design contitutes skills and knowledge quite different from even high end audio design. Furthermore the PCB layout often requires experience not found in books, often to be learned the hard way...even if your circuit is perfect, a bad PCB design can yield a totally nogo result, struggling with stray capacitance, signal crosstalk etc.
A top notch receiver requires a RF gain of 100-110 dB before the demodulator. Getting a stable design is difficult at best, - but of course, there are ways.....
Then the design adresses contradicting requests,- a very good mixer must produce well controlled 2nd harmonics, and nothing more in terms of higher order harmonics, the RF amplifiers should produce no harmonics, - of course....
The local oscillator should be frequency stable, and as pure as possible,- no phase noise etc.etc ( something for the CD clock bunch..) and so on and so forth.......
I have been reading both RF and audio mags for more than 30 years, and FM receivers have been rare, - good ones even rarer...
I have found only a couple of very good ones in total,- on in Ham Radio mag " UKW Berichte" in the early 70s, and two in Elektor in the late 80s and early 90s, all of them using parts I strongly suspect is no longer available, - including the frequency synth chips used in the latter two.
Working professionally if RF and instrumentation, and with audio as a long time hobby, the design referred by Cheff is a rather average one,- if a circuit board can be made. Except for the kicks of building radio circuits, which I fully understand, any 100-200 $ tuner in the shop will give rather similar quality, soundwise....and quite frankly, - listening to the radio stations in my corner of the world does not require anything better qualitywise..
A top notch receiver requires a RF gain of 100-110 dB before the demodulator. Getting a stable design is difficult at best, - but of course, there are ways.....
Then the design adresses contradicting requests,- a very good mixer must produce well controlled 2nd harmonics, and nothing more in terms of higher order harmonics, the RF amplifiers should produce no harmonics, - of course....
The local oscillator should be frequency stable, and as pure as possible,- no phase noise etc.etc ( something for the CD clock bunch..) and so on and so forth.......
I have been reading both RF and audio mags for more than 30 years, and FM receivers have been rare, - good ones even rarer...
I have found only a couple of very good ones in total,- on in Ham Radio mag " UKW Berichte" in the early 70s, and two in Elektor in the late 80s and early 90s, all of them using parts I strongly suspect is no longer available, - including the frequency synth chips used in the latter two.
Working professionally if RF and instrumentation, and with audio as a long time hobby, the design referred by Cheff is a rather average one,- if a circuit board can be made. Except for the kicks of building radio circuits, which I fully understand, any 100-200 $ tuner in the shop will give rather similar quality, soundwise....and quite frankly, - listening to the radio stations in my corner of the world does not require anything better qualitywise..
Miguel2,
Philips' SA602 and SA604, along with Application Note AN1993 could make a good starting point. But browse their website, you may find something interesting...
AuroraB,
Glad to have at last an expert advice about Ryder's design. For a dummy head like me, what makes you qualify it as "average" ?
I've too noticed Elektor's designs, but I'm absolutely not qualified to say they're good or not... Will try to dig in my old issues of the magazine, just to check we're talking about the same designs...
By any chance, do you have a copy of the Ham Mag article ? Should be nice...
Philips' SA602 and SA604, along with Application Note AN1993 could make a good starting point. But browse their website, you may find something interesting...
AuroraB,
Glad to have at last an expert advice about Ryder's design. For a dummy head like me, what makes you qualify it as "average" ?
I've too noticed Elektor's designs, but I'm absolutely not qualified to say they're good or not... Will try to dig in my old issues of the magazine, just to check we're talking about the same designs...
By any chance, do you have a copy of the Ham Mag article ? Should be nice...
Cheff......
I took time to read through the referred article once again, this time more thoroughly...
This time, I also recognized Wayne Ryder's name from my earlier subsriptions to various ham radio magazines, with several excellent articles............and a closer look probably says that this design is not bad at all, - albeit incomplete as a project, as it lacks the both stereo decoder and the control CPU to drive the frequency synthesizer. What mr.Ryder does here, is to address some of the problems I described, with conflicting demands on a.o. the RF front end. He also points to the importance of linear phase and group delay in the MF filters, here by using a Murata filter I don't know. Most average receivers will indeed use Murata ( or Toko ) filters of lower quality, price appx. 1$ or less piece. If you look to the Elektor designs, they use two rather expensive crystal filters from Toyocom ( as did the UKW article ). 15 years ago, I could still get hold of these for appx. 40-50$ apiece, --nowadays I don't have clue...have tried sarching but no luck....
He also addresses the problems of detector linearity andS/N by seemingly very careful component selection...
For the "UKW Berichte" article, I should have a bad copy somewhere, but it is very close to the later of the Elektor designs, except for the synthesizer, which of course is "Flintstone tech", by comparison......
To sum up,- by closer inspection, this article could be the basis of a very good kit, if complete. With the current state of affairs, it is a true "research project"
BTW- the Elektor designs should still be managable, if you can find the parts, filters and synth chips in particular. And- I guess you would have to write your own program, - I don't think Elektor still delivers the EPROMS ??? If I can be of any help,-ask away.....
I took time to read through the referred article once again, this time more thoroughly...
This time, I also recognized Wayne Ryder's name from my earlier subsriptions to various ham radio magazines, with several excellent articles............and a closer look probably says that this design is not bad at all, - albeit incomplete as a project, as it lacks the both stereo decoder and the control CPU to drive the frequency synthesizer. What mr.Ryder does here, is to address some of the problems I described, with conflicting demands on a.o. the RF front end. He also points to the importance of linear phase and group delay in the MF filters, here by using a Murata filter I don't know. Most average receivers will indeed use Murata ( or Toko ) filters of lower quality, price appx. 1$ or less piece. If you look to the Elektor designs, they use two rather expensive crystal filters from Toyocom ( as did the UKW article ). 15 years ago, I could still get hold of these for appx. 40-50$ apiece, --nowadays I don't have clue...have tried sarching but no luck....
He also addresses the problems of detector linearity andS/N by seemingly very careful component selection...
For the "UKW Berichte" article, I should have a bad copy somewhere, but it is very close to the later of the Elektor designs, except for the synthesizer, which of course is "Flintstone tech", by comparison......
To sum up,- by closer inspection, this article could be the basis of a very good kit, if complete. With the current state of affairs, it is a true "research project"
BTW- the Elektor designs should still be managable, if you can find the parts, filters and synth chips in particular. And- I guess you would have to write your own program, - I don't think Elektor still delivers the EPROMS ??? If I can be of any help,-ask away.....
CheffDeGaar said:Miguel2,
Philips' SA602 and SA604, along with Application Note AN1993 could make a good starting point. But browse their website, you may find something interesting...
AuroraB,
Glad to have at last an expert advice about Ryder's design. For a dummy head like me, what makes you qualify it as "average" ?
I've too noticed Elektor's designs, but I'm absolutely not qualified to say they're good or not... Will try to dig in my old issues of the magazine, just to check we're talking about the same designs...
By any chance, do you have a copy of the Ham Mag article ? Should be nice...
Everything is "critical" -- but there are circuit diagrams and PCB layouts for much lower noise 2 meter (and up) front ends all over the place., there are now DDS chips with eval boards readily available.
while we are at it, someone should also make a half-decent a.m. receiver again.
Hello, Norway !
Nice place (been there 2 years ago), but expensive one
AuroraB...
(with the nice solar eruptions I was told we have these days, you should be glowing strong ) - Sorry, couln't resist- hope you don't mind
Thanks for taking the time to reread Mr Ryder's article ! A small search in the news groups shown me other people share your opinion. So it is worth a try...
Well, that's a point, but not the major issue IMHO. If only I could have something working with basic implementations of such features, I should be happy... But this sure should be addressed, and solutions are somewhat numerous for this.
Specs are here. Do these specs sound good to you ? Prices are not too high, approx between 1 and 2 Euros...
Wow, not exactly cheap !!! I didn't have the time to check my Elektor issues, normally this WE...
I totally agree regarding component selection... I've already sourced the major part of he components, but I have some difficulties with the coils... The Toko coils (L6,L7,L9,L10,L12) can be sourced via Digikey for US or BEC (UK), but I could find neither the IF quad coil from Sumida (235S01 SNY-074-1919A) - no reference of it at Sumida's website -, nor the Toko equivalent given by Sanyo in the LA1235 datasheet (Part nr : Q228CEL-1077B). All I found is a toko quad coil (Q228CEL1064L on BEC's site. But I don't know if it can be used without problems.... Do you have any hint on sourcing the original Sumida coil, or if the last Toko quad coil would fit in the design ?
The other (and last ) main thing that puzzles me in this design concerns the input coil (L6 on the schematic) : as far as I know, the MC 120 coils don't have intermediate winding. And here, the RF input seems to enter the circuit through such an arrangement... Do I have to make it myself, calculating the impedance required to have 75 Ohms, and adding an entry point to the coil to get this input impedance, or is there any "logical" explanation ?
Thanks a lot . If the German article is close to Elektor's, I will try to stick to the latter. The filters availability frightens me, but who knows... Will serach my papers this WE...
. Thanks for being so helpful. And I'm sure we can manage to get something working, and of nice quality, despite the awful quality of the majority of FM broadcasts....
Cheers,
Nice place (been there 2 years ago), but expensive one
AuroraB said:
AuroraB...
(with the nice solar eruptions I was told we have these days, you should be glowing strong
) - Sorry, couln't resist- hope you don't mind Thanks for taking the time to reread Mr Ryder's article ! A small search in the news groups shown me other people share your opinion. So it is worth a try...
Well, that's a point, but not the major issue IMHO. If only I could have something working with basic implementations of such features, I should be happy... But this sure should be addressed, and solutions are somewhat numerous for this.
Specs are here. Do these specs sound good to you ? Prices are not too high, approx between 1 and 2 Euros...
Wow, not exactly cheap !!! I didn't have the time to check my Elektor issues, normally this WE...
He also addresses the problems of detector linearity andS/N by seemingly very careful component selection...
To sum up,- by closer inspection, this article could be the basis of a very good kit, if complete. With the current state of affairs, it is a true "research project"
I totally agree regarding component selection... I've already sourced the major part of he components, but I have some difficulties with the coils... The Toko coils (L6,L7,L9,L10,L12) can be sourced via Digikey for US or BEC (UK), but I could find neither the IF quad coil from Sumida (235S01 SNY-074-1919A) - no reference of it at Sumida's website -, nor the Toko equivalent given by Sanyo in the LA1235 datasheet (Part nr : Q228CEL-1077B). All I found is a toko quad coil (Q228CEL1064L on BEC's site. But I don't know if it can be used without problems....
Do you have any hint on sourcing the original Sumida coil, or if the last Toko quad coil would fit in the design ? The other (and last
) main thing that puzzles me in this design concerns the input coil (L6 on the schematic) : as far as I know, the MC 120 coils don't have intermediate winding. And here, the RF input seems to enter the circuit through such an arrangement... Do I have to make it myself, calculating the impedance required to have 75 Ohms, and adding an entry point to the coil to get this input impedance, or is there any "logical" explanation ? Thanks a lot . If the German article is close to Elektor's, I will try to stick to the latter. The filters availability frightens me, but who knows... Will serach my papers this WE...
Just look above
. Thanks for being so helpful. And I'm sure we can manage to get something working, and of nice quality, despite the awful quality of the majority of FM broadcasts....Cheers,
Miguel2,
Philips' SA602 and SA604, along with Application Note AN1993 could make a good starting point. But browse their website, you may find something interesting...
Application Note AN1993 has moved:
https://www.nxp.com/docs/en/application-note/AN1993.pdf
A standard application of a modern car radio chip (like the TEF6688, which Mouser can supply with 16 weeks lead time) would give you state-of-the-art reception performance and good audio performance with no components that require manual tuning. The main problem is getting hold of complete datasheets and application notes. As everything is controlled via I2C, you would have to write your own microcontroller program to control the thing.
For those who like valve circuits, there were quite some DIY radio designs published in hobby electronics magazines in the 1950's, although many of them receive AM only. Those radios invariably have lots of manual tuning points.
January 2019 edition of Silicon Chip magazine has a DIY radio receiver for AM, FM and DAB+ based on the Si4689 chip which they will be offering a PCB and parts list for soon. Looks interesting but not cheap to build and you have to either buy the magazine or at least the article and subsequent ones yet to be published.
Hi guys,
ok if you can build a PCB and source the parts for the Wayne R SUPRX, I'm certain you will sell a few units to the DIY community. but sourcing the parts won't be easy.
Today the way to build a FM tuner is to do it 100% using DSP. The current best tuner on the market uses such approach (Accuphase t-1200). Years ago the A/D chips allowed for a full digital conversion and with a FPGA chip much better performance was achieved than possible with analog approach and parts which require extensive tuning and alignment anyway. a fellow in japan did this in 2009 and shocked everyone.
Look at how cheap it can be made today:
New DSP & PLL LCD Digital Stereo FM Radio Receiver Module w/Serial Control | eBay
Another suggestion, get a old bedroom alarm clock radio, it might have a wonderful sony (analog tuner on a chip CXAxxxx) an engineering marvel of the past. Pull all the circuit and parts and the dial with dial string and try to assemble your own radio (call it a kit) you will see not so easy to get the dial string and dial pointer to align on the station.
But seriously, look into FPGA or DSP solution, you will be amazed at the performance.
With google and translate you will find some kits and parts in the DIY JAPAN community going back to 2012.
Your best to learn by modifying an existing tuner. I don't advise the I2C based chips, big project... NXP had some good ones a few years ago but discontinued now.
You can try a tube based tuner too, simpler circuit but you still need to find rare vintage coils and IF transformers (10.7 Mhz) etc... just reproduce a circuit.
Like stated earlier, FM tuner is even harder than MC phono preamp in terms of gain required and noise levels needed. RF stage, IF stage and AF stage all very specific competences each with design challenges. Hence doing it all in software on a DSP is highly recommended.
good luck, this is ambitious but will be rewarding in satisfaction.
cheers
Paba
ok if you can build a PCB and source the parts for the Wayne R SUPRX, I'm certain you will sell a few units to the DIY community. but sourcing the parts won't be easy.
Today the way to build a FM tuner is to do it 100% using DSP. The current best tuner on the market uses such approach (Accuphase t-1200). Years ago the A/D chips allowed for a full digital conversion and with a FPGA chip much better performance was achieved than possible with analog approach and parts which require extensive tuning and alignment anyway. a fellow in japan did this in 2009 and shocked everyone.
Look at how cheap it can be made today:
New DSP & PLL LCD Digital Stereo FM Radio Receiver Module w/Serial Control | eBay
Another suggestion, get a old bedroom alarm clock radio, it might have a wonderful sony (analog tuner on a chip CXAxxxx) an engineering marvel of the past. Pull all the circuit and parts and the dial with dial string and try to assemble your own radio (call it a kit) you will see not so easy to get the dial string and dial pointer to align on the station.
But seriously, look into FPGA or DSP solution, you will be amazed at the performance.
With google and translate you will find some kits and parts in the DIY JAPAN community going back to 2012.
Your best to learn by modifying an existing tuner. I don't advise the I2C based chips, big project... NXP had some good ones a few years ago but discontinued now.
You can try a tube based tuner too, simpler circuit but you still need to find rare vintage coils and IF transformers (10.7 Mhz) etc... just reproduce a circuit.
Like stated earlier, FM tuner is even harder than MC phono preamp in terms of gain required and noise levels needed. RF stage, IF stage and AF stage all very specific competences each with design challenges. Hence doing it all in software on a DSP is highly recommended.
good luck, this is ambitious but will be rewarding in satisfaction.
cheers
Paba
Among many other projects I have been designing and constructing an FM receiver. So far, the tuner works (~ 1dB NF), the IF section needs a different (2nd IF) filter, and the demodulator only exists as simulation: analog PLL with threshold extension (~8 dB improvement over standard analog PLL). Same for the stereo decoder. Could take a couple of years before everything works in accordance to simulation ( = useful signal for mono reception <0.1 uV / 75 ohm).
Modern car radio chips typically have digital IF processing with lots of embedded firmware to improve weak signal reception. If you want to make something similar with an FPGA, there are two issues: whistles due to interference from the FPGA to the receiver and having no access to the proprietary weak signal processing firmware.
I built an analogue FM tuner some years ago. Mainly conventional circuitry (used Hitachi FM and stereo decoder chips) but with a VHF front end informed by my experience with the 2m amateur band. I guess if I tried to do it again today I would find that many of the components are no longer available.
This is what I still use today (post #117) :
https://www.diyaudio.com/forums/analogue-source/8089-fm-am-tuner-12.html#post2239643
The TDA7021/7040 chip set can still be had for little over 3€.
The rest are trivial.
Great sound, for such simplicity,
Patrick
https://www.diyaudio.com/forums/analogue-source/8089-fm-am-tuner-12.html#post2239643
The TDA7021/7040 chip set can still be had for little over 3€.
The rest are trivial.
Great sound, for such simplicity,
Patrick
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