TEF6686 DSP Chip and the Qodosen SR-286

Many thanks to SWLing Post contributor, TomL, who writes:

A couple of weeks ago, “Radio Jay Allen” sent out a review of a Chinese portable using a different DSP chip from NXP called the TEF6686 usually used in car radios with lots of features. I also notice that the description for the new 2024 WRTH lists an in-depth an article about the TEF6686 chip. Does anyone else know about the new chip or the portable that was reviewed? Is it better than the current crop of portables based on Silicon Labs chips?

Here is a link to the review of the portable radio:

Qodosen SR-286 AM/LW/FM/SW High Performance Portable

Click here to check out the Qodosen SR-286 on AliExpress. 

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26 thoughts on “TEF6686 DSP Chip and the Qodosen SR-286

  1. KPL

    narkspud said: “One bit of weirdness I stumbled across … Americans, do not set the FM to 200 kHz steps. It defaults to the even numbers, skips the odd ones where the stations actually are, and messes up your day until you figure out what the problem is.”

    I haven’t tried this radio, but sounds like a serious misunderstanding by the designers. The 200kHz steps mode were I would expect actually intended for American use, but that they made the blunder of tuning to *.0/*.2/*.4/*.6/*.8 rather than the valid *.1/*.3/*.5/*.7/*.9 carrier frequencies.

    I do not believe there is anywhere in the world where 0.2MHz FM steps are used, that end in even, instead of odd, numbers after the decimal point.

    Surely this will be fixed in later revisions of the radio?

    Reply
  2. Mike S

    The background AM/SW noise issue has been well researched by Gary DeBock on the ULDX forum. He confirms (as you suspect) that it is from the LCD display controller, and appears to be a QC issue as it is more or less apparent on different specimens. I am reminded of the CCrane Pocket which has an identical button-press option to turn off the display for the same reason.

    I also notice something odd on FM – a kind of sputtering in the otherwise uniform white noise in between stations. But signal capture on weak FM signals is so phenomenal that it is entirely incidental and disappears when actually tuning a signal.

    Reply
  3. Noel F

    I’ve had my SR-286 for a few weeks now, and it doesn’t disappoint. Sure, the internal ferrite could be longer, but outdoors using the whip antenna it’s outstanding on MW. On LW, I’ve found signals that I’ve never pulled in before. Same on SW, the bands are fat with signals. Just amazing…

    The only quibble I have is that on weaker MW signals there’s a ticking (like a car blinker) when listening through headphones. It’s somehow associated with the LCD display as it goes away when I simultaneously press 1 & 3 to blank the display.

    It’s no biggy as the ticking isn’t there at all when listening through the speaker and I can mute it by blanking the LCD when listening through headphones.

    Reply
  4. Arthur Pirika

    I’ve ordered one of these, looking forward to it being here. Lack of SSB isn’t a bother for me, I have other receivers for that. I have a couple of questions about operation, though. I’m assuming that like other digital radios, if you use the tuning knob or up/down buttons to tune, if you get to one end of the band, the system just wraps back around to the other end. Kind of wish there was an option to stop at the ends of the band like an analog tuner would. Speaking of tuning around bands, if you use the meter+/- buttons on SW, will pressing those buttons always go to specific frequencies on the band, or does the radio remember your position in each meter band segment?
    Thanks for any help answering these questions.

    Reply
  5. narkspud

    Some, er, nonconformist thoughts about my SR-286, which arrived a couple hours ago, on the off chance that they may be helpful to someone:

    First and foremost, boy howdy do you need that manual! The English is pretty good, the organization not so much. But this is not an intuitive radio AT ALL. You will need to refer to it constantly.

    The reception does not disappoint. The thing seems to work similarly to the celebrated Sony XDR-F1HD, in that it pulls listenable stereo reception out of stations it’s got no business receiving in stereo, and it apparently does it by applying noise reduction to the stereo subcarrier. And like the XDR-F1HD, this creates some odd artifacts in the stereo imaging when the volume gets low enough. Worth it? Why yes, yes it is, if you’re trying to listen to weak signals. But like the XDR-F1HD, it’s not ideal for the strong local signals, since you lose the benefits but still get the artifacts. Of course you won’t hear that through the speaker, which, by the way, punches way above its size.

    Stereo or not, it does indeed pick up stations that you didn’t know were even there. COOL.

    The headphone audio quality, just speaking in general, is … digital. Hard to describe, exactly, but it has this vaguely whistley quality that I associate with MP3s. It’s not terrible, but it’s bad enough to bug my nitpicky self, so this definitely won’t be my go-to radio for listening to the local FMs with headphones, since I have other portable radios (DSP ones!) that don’t have this issue. But for more distant signals? Absolutely!

    The “different processing methods” on FM failed to impress, and I have no plans to ever use them. They don’t seem to make a bit of difference to my reception – all they do, as far as I can tell, is noodle with the EQ on the high frequencies. Or that’s the effect anyway. I don’t see the point.

    AM and Shortwave? Well, they also have some kind of dynamic noise reduction going on. You can hear it pumping on weaker signals that are running talk programming. Again, not a problem given the benefits, but again, maybe not ideal for some uses. Same reception report as the FM – Hey, where did all those stations come from?

    But here’s the thing. If you’re still looking for a genuine wide bandwidth AM receiver (like I am), and saw that 8 kHz spec (like I did) … move on, this is not the droid you’re looking for. They’re referring to the RF bandwidth, not audio. So the 8 kHz setting here is equivalent to the 4 kHz setting on, say, the XHDATA D-109. This spec switcheroo is my biggest disappointment with this radio, but it’s happened before (hi Tecsun!) and I kind of expected it.

    A brief rant on this topic, not for the first time: Hey, chip and radio makers, the NRSC standard in the US is 10 kHz AUDIO BANDWIDTH, that’s 20 kHz RF, and it would be nice to be able to actually HEAR it before my ears get too old. Grarrrrr!!!

    One bit of weirdness I stumbled across … Americans, do not set the FM to 200 kHz steps. It defaults to the even numbers, skips the odd ones where the stations actually are, and messes up your day until you figure out what the problem is.

    And one more. You know all those people reporting that it comes without a battery? Mine came with a battery. Unbranded. Capacity unknown at this time.

    Would I buy it again, knowing what I know now? Yeah. The reception is a killer app, regardless of my other quibbles. And it’s way more convenient than that Sony.

    Reply
    1. narkspud

      One correction, having fooled with it quite a bit more: My comparison to the XDR-F1HD was a bit premature, and I blame my overenthusiasm for the reception it was delivering. It is NOT doing the Sony NR on the subcarrier thing, or at least not very effectively. It appears to just have some sort of dynamic noise reduction applied to the main audio. Effective, but absolutely not XDR-level effective. Most of the magic is in just pulling the actual signals out of the noise.

      One new minor grouse about something I should have noticed before ordering – not a big deal since I didn’t buy this thing to listen to CB – but its shortwave frequency coverage only goes up to 27.000 MHz. What’s up with that?

      Since some folks report having trouble with the clock, and I figured the darn thing out, here’s how it works.

      Step 1: With the radio off, long-press the M/TONE button and use the tuning knob to choose YOUR time zone. (Note: The radio doesn’t recognize Daylight Savings Time, so you’ll have to choose the time-zone-to-the-right-of-yours if you want to set DST. That’s Caracas for you East Coasters.) Short-press the all-purpose “PAGE” button to enter.

      Step 2: Set your local time by long-pressing “PAGE”. That’s the big clock. 24-hour time only. This works exactly the way you’d think it does.

      Step 3: Long-press the M/TONE button again, and choose ***the time zone that you want to see on the small “WORLD” clock**. Short-press “PAGE”.

      You’re done. The radio maths out the difference between your time zone, from step 1, and the “WORLD” time zone, from step 3. Obviously you can choose any two time zones you want to, but the one you enter BEFORE you adjust the time itself goes to the big clock, and the one you enter AFTER you adjust the time goes to the little “WORLD” one.

      You can change the “WORLD” clock’s time zone any time by just turning the radio off, going into “M/TONE”, and making the change, but if you want to change the BIG clock’s time zone (like, say, when Daylight Saving Time ends) or adjust the time itself, you have to go through all three steps again, in order.

      And one last shower thought. SR stands for “small radio”. Discuss.

      Reply
      1. Arthur Pirika

        So, re, the clock. I’ll provide a concrete example for myself here to make sure I understand this right. I live in Western Australia, so.
        1. Set the world clock timezone to either of the +8 options (Hong Kong or Beijing). I don’t think either of those locales observe DST, as we don’t.
        2. Set time to current time here at home. Sidenote, can you use the numeric keys to input digits here? Or just the tuning knob.
        3. Set secondary timezone, say to +0-GMT.
        Done.
        Arthur

        Reply
  6. José Macias

    This radio is very goof for tuning long wave. Simply with its internal ferrite antenna I have been able to listen in Huelva (Spain) to Radio Medi 1 at 171 Khz located in Nador and Radio Argel at 252 Khz located in Tipaza. Placing the radio next to a corner in the most favorable point of the house they sound
    almost like local stations. To improve reception considerably, I recommend building a long wave loop antenna following the instructions contained in this link:
    http://www.vandenbalck.eu/webdata/LONG%20WAVE%20PORTABLE%20LOOP%20ANTENNA.pdf

    Reply
  7. Mike S

    My SR-286 arrived today. Many thanks to Jay Allen for posting the manual on his web site, without which this would have been a very frustrating experience. Just some quick observations to supplement the more technical and experienced reviewers. I have only used it with the internal antennas so far, compared to the D-808 which happened to be nearby and have a charged battery. The SR-286 comes with a high quality button-top 18650 li-ion cell (undeclared on the mailing labelling) inside a clamshell case which crams the charging cable right against the LCD display bezel- so the protective film is pre-damaged in transit. I’m surprised to see a rather large battery accommodated in a case about the size of the CCrane Skywave.

    First, this is a very interesting pocket radio. Its overall external design borrows a lot from predecessors, especially the Redsun-produced models and clones, but that’s where the similarities end. First impressions have significant “wow” factor reminiscent of the unboxing of the first CC Skywave. I’m counting the days before buying a spare (the lack of SSB, AIR, etc notwithstanding) in case, as feared, these can not be produced forever. It would also be great if they produced a larger version having the companion HD/DRM coprocessor available for this chipset.

    My comment about the manual stems from the observation that the user interface can be extremely challenging. As Jay commented in his review, the number of functions, adjustments, and tweaks far outnumber what can be done with the Silabs-based portables we have been familiar with over recent years. To access those things using such a small set of keys requires a large number of variations of keypresses: short press, long press, press two keys together, press while powered on, powered off, etc. There is a size limit to the number of those functions which can be labelled in the tiny space on the front panel, and many are not exactly intuitive (e.g. the PAGE button commonly functions like the “Accept/Enter key. Who would know without the manual?) Yet I have still not been able to successfully program the local and world time to display as intended. Either both end up the same, or the offset from GMT is in the wrong direction.

    The speaker audio (which features both a voice and music mode) is rich and full, to my ears reminiscent of the XHDATA D-109. It is quite pleasant to listen to at length without fatigue. There is no discernible noise floor from the amp, and FM via headphones is full fidelity. Volume seems quite adequate.

    Sensitivity on all bands (well, except LW where there is no good way to test here) is exemplary on the internal antennae; at least as good as the D-808. As Jay noticed, I also pulled in some fringe FM stations that I needed to go to the car to confirm were actually there. FM interstation noise is weird; kinda warbly; and (like fringe reception) is altered by which of the 3 FM “processing modes” you choose. The default results in considerable loss of treble on weak signals; I find the “2” position to be the most pleasing. I left the FM bandwidth to “auto” and the pre-emphasis to 75.

    Many familiar functions have new tweaks. For instance, manual tuning can be programmed as fast, slow, stop, or auto seek; the latter offering choices of full stop on finding the next signal (threshold programmable, of course) or a user-defined delay before moving on. Just a sample….

    As one could imagine, it’s going to take a while to experiment with all of the unmentioned capabilities, tweaks and performance adjustments. But it’s quite refreshing to find such amazing performance and ability to customize in a tiny radio that fits in your pocket. Hoping I’ll actually get some sleep tonight…

    –mike

    Reply
  8. Brian

    I’m glad it doesn’t have SSB. There is almost nothing to hear on SSB except boring ham radio amateurs talking about their gear or drunken vulgarity. I guess if you’re a ham and that sort of discourse interests you then ok, but don’t you already have other radios with that capability? Do you not listen to other broadcasts? Whatever

    Reply
    1. Renard

      Compared to what’s available in the USA, in English, on shortwave, I enjoy the ham radio conversations a lot. Especially the technical ones. Haven’t found any “vulgarity” for a while, though I know it’s around. I am a ham, but no HF station right now, just local VHF/UHF.

      Reply
    2. jonradio

      What I really miss in this, and all my other radios, is the SSB-like feature of being able to listen to USB or LSB, Upper Side Band or Lower Side Band. Really helpful when a station on the adjacent frequency is so strong that you normally hear a swish-swish “slop” as we used to call it.

      Reply
  9. Andrew (grayhat)

    Judging from the infos available from NXP

    https://www.nxp.com/products/audio-and-radio/analog-digital-radio-and-audio/low-if-tuner-high-performance-one-chip:TEF668X

    the IC is some kind of “SoC” (System on Chip) implementing a whole receiver and requiring just a few external components, reading the tech details, the IC should allow to add an SSB decoder, but that would probably raise the price of the receiver, that being said, I won’t expect high level performances from such a receiver

    Reply
    1. Mike Bennett

      ..this kind of car radio chip can be used on AM/FM alarm clocks, pocket radios, Marine Band, Air Band, etc., and even a cheap $20 radio can sound so……………..good…! This is close to the “Holy Grail” of radio tecjh..!

      Reply
  10. mangosman

    https://www.nxp.com/docs/en/brochure/75017468.pdf is 10 years old! With the TEF6688 and a single coprocessor this receiver could also receive HD radio and Digital Radio Mondiale. The https://www.nxp.com/docs/en/data-sheet/SAF360X_FAM_SDS.pdf coprocessor is 9 years old. The screen would have to be replaced with a colour one for the coloured images transmitted.

    A more detailed review https://min.news/en/digital/324ee8924e2c6d9d2d61c7106754aece.html#google_vignette all though the site advertising is excessive.

    Reply
  11. Daniel Robinson

    This radio, obviously one of the latest copying old Sony designs (think ICF-SW1) just isn’t as good as it should be. No SSB is a big miss. FM bandwidths are interesting. We can hope that new versions of this will correct the SSB oversight.

    Reply
  12. Art McLaughlin

    The lack of ssb is unfortunate. So many nice features on this radio but lack of ssb is a no sale for me. I will stick with my Ccrane Skywave SSB.

    Reply

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