Video: How to calibrate the Tecsun PL-660 frequency offset

Many thanks to SWLing Post contributor, Mike Mander, who writes:

I’ve recently really been enjoying Thanks for having such a great resource online with shortwave radio and hardware reviews, tips and more! I started listening to shortwave on an old Philips portable receiver back in the late 70’s as a teenager. Recently, after decades of not listening to shortwave, I decided to buy an Eton ‘Grundig Edition’ Satellit radio and in no time at all, I had also acquired a C.Crane Skywave SSB and now, within the last week, a Tecsun PL-660.

[…]I thought I’d record a video showing how one can calibrate AM, FM, SW wide-bandwidth as well as SW narrow-bandwidth independently, and how to reset those calibrations back to factory default. I have not heard it mentioned anywhere that one can calibrate both wide and narrow bandwidth SW modes independently.

Online, I have read about many people being disappointed in their PL-660’s wide-bandwidth frequency calibration, where often being on-station results in the frequency being up to 5 kHz too low, and it seems many simply return their radios as defective, not realizing how easy it is to recalibrate. This is the first “instructional” video of this sort that I’ve ever posted online, so you’ll have to pardon if I am perhaps not explaining things clearly enough:

Click here to view on YouTube.

Excellent video, Mike! You’ve done a fine job making the explanation clear and easy to follow. Thank you for sharing!

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34 thoughts on “Video: How to calibrate the Tecsun PL-660 frequency offset

  1. greg schmidt

    Mike You are a radio God! calibration works as you directed in video! My unit mfg date 10-2018
    The firmware comes up as 6620 vs 6622 but cal works . Being part of SWL ( and Mike) has saved me from putting up with a substandard radio. Thks again

  2. StratMan

    I’ve just purchased a Tecsun PL-660 from the official XHDATA store via the Malaysian Lazada e-commerce platform. The seller, Carmen was communicative and she assured me that the latest units come with the 6622 firmware.

    Sure enough, when I received it within a week the first thing I checked was its firmware and it did indicate “6622” on the top right of the display. Mike Mander’s video tutorial on YouTube worked on my radio and I was able to recalibrate certain stations that are off by a few kHz. 🙂

    I’m a little confused why Tecsun still makes the PL-660 when they have also released the PL-680. My old receiver is the Sony ICF-SW7600G (not the GR version) which I had since 1999, but has not been working for over a decade. I remember taking it to the Sony Malaysia service center but they declined to repair it, citing that the model has been discontinued and they could not get spare parts.

    Back in 2007, I saw the ICF-SW7600GR for the first time at a Sony sales showroom but it lacked SSB. I didn’t buy it. I knew it was the crippled version which was meant for the Middle East market, which prohibited shortwave radios with SSB functionality and its coverage capped at 26.1 MHz instead of 30 MHz. Furthermore its FM coverage was limited to 88-108 MHz, instead of 76-108 MHz for the North America and Japan market.

    I suspect that authorities in countries like Saudi Arabia restricted its citizens from tuning into frequencies above 26.1 MHz on shortwave and lower than 88 MHz on FM band and perhaps listening to ham operators on HF.

    My first Sony ICF-SW7600G was the Middle East version and I’m not sure how the electronics dealer got that model. Two months later in 1999, I was shocked to find the same dealer selling the non crippled 7600G version with SSB and full 150-29999 kHz coverage! I bought that radio (it was the only unit for sale) on the spot and later sold my first 7600G to a friend of mine. He still has it to this day and it’s in perfect working condition!

    BTW, today Malaysia no longer has silly restrictions on the types of receivers one can buy but Sony Malaysia had long stopped selling the ICF-SW7600GR. So I ordered the Tecsun PL-660 from China and it had no problems going through customs.

    It seems that later versions of the PL-660 are equipped with the automatic memory preset sorting function. My radio (with the 6622 firmware) has it and it’s activated by holding down the AM BW button while the unit is switched off.

    What it does is that it automatically sorts the memorized frequencies in ascending order and also deletes duplicate frequencies. That’s quite useful as I sometimes end up adding the same frequency two or three times.

    I did some additional research on the PL-660 and found out that its Narrow and Wide AM selectable bandwidths are 10 and 18 kHz respectively. This is my first shortwave receiver with user adjustable bandwidth filters, therefore I don’t know if 10 kHz is not narrow enough for a Narrow filter.

    Given that I’ve not purchased a new shortwave receiver in over 20 years, I thought I’d try the PL-660 as I wasn’t sure if the slightly more expensive PL-680 would give me a much better performance.

    I read reviews of the more compact and cheaper PL-330 (with a new firmware for 2021) but I’m not sure if I like the “chuffing” (staccato muting) effect while turning the tuning knob. It seems that Tecsun’s DSP based receivers suffer from this anomaly. The PL-660 relies on the traditional PLL synthesized receiver technology and it tunes like an all analog shortwave radio.

    I’ll see how far my renewed SWL hobby goes. If my interest deepens I might just get the tabletop (or porta-top?) Tecsun S-2000 receiver later this year. Or perhaps the Tecsun PL-990 or the first generation Sangean 909X. 🙂

  3. Kevin P MacNutt

    This trick also works with the Tecsun PL-680 which electronically is basically the same radio as the PL-660. My FM was off causing all my stations to be off by .5. This really worked wonders!!! Thank you!

  4. Patrick Roos

    In your video you press the Air button. I live in the Netherlands myself and discovered that I have to press the SYNC button on my PL-660 instead of the AIR button. I thought this supplement would be valuable. Greetings Patrick.

  5. Henry

    I prefer the “angular” look of the PL-680 over the more “curvy” PL-660. At the moment Sony’s ICF-SW7600GR is my “workhorse.” I modified my Sony with better filters and “slowed down” SSB fine tuning; the only thing missing is the ability to keep the light on. I might do this next. I would consider a PL-680 with this calibration capability. The first radio that I can remember with calibration capability was the AOR AR7030 from many years ago. This radio was almost perfect and expensive. If anyone from Tecsun reads this, please consider putting a PL-680 or PL-660 into a PL-600 chassis (complement the knob with separate Up/Down buttons).

  6. Jennifer

    Success! 🙂
    Your instructions work, i managed to correct AM and FM offset. Its nice to finally see the correct frequency on the display.
    Im so glad mine have the ability to correct offsets.

  7. Jennifer

    Thanks a lot for this information very interesting. Received my PL-660 a few days ago and played around extensively with it over the weekend. I noticed mine does the backlight blinking when I press “Air” for a few seconds but had no idea why it did that, now I know 🙂

    The recalibration seems to be available on both AM and FM on mine which leads me to conclude I have one of the later models. I noticed the frequencies on AM and FM are a little off on mine eg LM Radio is supposed to be on 702 KHz AM but is only clear when I select 705 KHz and on FM all stations are also off by a few digits.

    I ordered my PL-660 on from a US seller.

    The following is also possible according to kaito’s website:

    Home How to Calibrate the PL660 on the FM Band ?

    How to Calibrate the PL660 on the FM Band ?


    1 Review(s) | Add Your Review

    How to calibrate the FM frequency ?

    SKU: PL660Calibrate

     Sign up for price alert

    Availability: Out of stock


     Add to Wishlist  Add to Compare

    Brand: Tecsun


    There is a Hidden function of the PL-660 : You can calibrate the FM Frequency the following steps: 
    There is a hidden function of this radio: You can calibrate the FM frequency by yourself, is that cool ? Yes, here it is how to do it : 
    Re-calibrating FM, radio needs to be on and set to FM band. Tune to the desired frequency/station you wish to listen to, press “SYNC” for about 3 seconds back light will flash. Tune up until the frequency/station sounds more clear press “1” to confirm re-calibration. If done correctly the correct frequency/station will be displayed on the display. Keep the battery in for all the time…

  8. Frank

    Mine shows 213, so calibration is not in its firmware but I must say after 5 years of heavy use it´s still pristine and dead-on-frequency and never had a problem.

  9. 13dka

    For anyone wondering why this doesn’t work: this is obviously a very recent change in the firmware, so firmware/production dates before late 2017 will not have this feature. How to find out firmware version and manufacturing date? With the radio off, press and hold the AIR button. After 10s or so the display will show a test screen showing all items on it, after a few seconds it will briefly show the manufacturing date (MM/YY, mine is “2-15”) where usually the frequency display is, and the firmware version number in the top right corner (“6618”).

    1. cobra2990

      That 2-15 number is certainly not the manufacturing date. My radio is manufactured in 01/18, visible on the sticker inside the battery compartment. My AIR button test also displays 2-15, but my firmware is 6620. I purchased my PL-660 in May, 2018 from anon-co. The 2-15 number is a mystery to me. Thanks for the info on the test.

  10. Peter Atkinson

    I, too have an older model that cannot be changed. Mine’s from 2012. All the “AM” bands on it are spot on, but the FM’s about 0.03 or 0.04MHz out of tune.

  11. Heath Hall

    Excellent! After 35 years of SWing I’m still technologically challenged, and was pleased to find even I could follow your simple instructions. You saved me from either the trouble of returning it or being slightly annoyed for years. Thanks Mike!

    Heath Hall
    Albuquerque, New Mexico

  12. Michael Meyer

    Nice video!

    Yes, it also works on my PL-680, which is made 11-2017 (just got it from Anon last week!).

    Best regards, Michael from Denmark

  13. Rob

    Great idea, but it doesn’t work on either of my 660’s either. One’s a late 2011, the other’s a mid-2017, both bought off Amazon, for what it’s worth. They both just go to airband and stay there.

  14. Mike Mander

    I will answer questions in more detail later when I have more time. In the meantime, I have sent an email to my technical contact to try and get clarification on PL-660 revisions. I was not made aware that this procedure might only work on the most recent versions of the PL-660, so apologies for getting people’s hopes up!

    1. Bill

      No worries, Mike. Thanks for posting. I am surprised and somewhat relieved to find so many withe same issue. I thought it might only be me with a ?. It is an annoying problem on an otherwise excellent portable.

  15. Jerry Decker

    I bought mine off eBay via a Chinese dealer late last year. I can get it to go into FM calibration, but not into Am calibration. No matter how long I depress the AIR button, the radio changes to the AIR band…. maybe I should have bought one from a US dealer…. oh well….

  16. Jorge Berríos

    I tried to do it with my Tecsun PL-660 and when I push and hold the air button it goes to aircraft’s band and does not do what you show in your video, Sir!

    1. James

      Pedro, I just got a new pl-680 with a sticker that seems to indicate manufacture in November 2017. The calibration technique in this article does work on my unit.

  17. Daniel Robinson

    Wow, thanks — I have to ask how you figured this out as these key combos
    have not been detailed elsewhere far as I know. This is tremendously useful
    for those of us who were puzzling over this issue.

    1. Mike Mander

      You’re welcome! That said, it seems that for many people, this trick doesn’t work unfortunately. How I came about this info was as follows…

      I originally was Googling PL-660 firmware versions, trying to figure out if there were significant differences between older and newer radios (and it seems there are!) and came across a mention of a firmware download for the PL-660 from Tecsun USA’s product listing page. The link can still be found listed with Google, but it now comes up as a 404 error. There was a download of a small binary file, surely way too small to actually be legitimate PL-660 firmware, but there were no other instructions on what to do with it, apart from a cryptic ‘Search for “youtube PL-660 frequency firmware” or something along those lines.

      When you do that, you get a link to this video… … which demonstrates the MW frequency calibration. When I first watched that video, I actually thought the radio shown was in SW mode and not MW, since I had watched it on my iPhone and since it was recorded by vertically oriented smartphone (presumably), it was really hard to see any detail. I clearly wasn’t swift enough to notice the obvious, that the frequency was on the MW band and not SW! This was also the only place online that I was able to find which showed the radio was capable of any sort of end-user calibration, without needing to tear into it and start messing with variable inductors and trim-pots, something I was not prepared to do on a new radio under warranty.

      Next, based on the tremendously positive recommendations they get from SW enthusiasts, I contacted Anon-co and sent an email asking about the Tecsun USA link, how to update PL-660 firmware (if it were even possible) and about the frequency shift calibration. I was emailed back by Anna, who was extremely helpful and answered all my questions in great detail. She mentioned there was no way an end user could actually update the firmware and then detailed how to calibrate FM and AM on the PL-660, so I decided to take a chance and order one. When I received it, sure enough, the wide-band SW was off by 5 KHz and I proceeded to simply try the calibration on the SW band and lo-and-behold, it worked like a charm. I think this even surprised Anna, but at that point, I somehow thought that maybe nobody else had stumbled upon this really useful feature yet. That was certainly naive on my part, since considering how many PL-660 radios seem to be in use, if this calibration had been available on much earlier versions, surely somebody else would have come across it by now, even if by accident!

      I now almost feel bad about posting that video, since it seems that only the very latest revisions of the PL-660 have this SW calibration capability. Even recent purchases at the end of 2017 might not guarantee one a PL-660 that can be calibrated, since any given store might have slightly older stock. This was one reason I chose Anon-co since by all accounts, that company would be one of the safest bets if one wanted the latest version of a Tecsun radio. Anyway, at least my video might help those with very recent PL-660 radios in need of calibration!

      I am waiting to hear back from Anna regarding PL-660 revisions and if there is any way of telling, by serial number, manufacture date, specific markings or redesign of the packaging etc., whether or not one can tell if any given PL-660 can be calibrated. I will post an update here once I hear back. At this point, I probably won’t have an answer until after the weekend.

      Lastly, my PL-660 came with a few other minor problems, but I just demonstrated the radio to a good friend of mine, and his wife fell in love with it, wanting it mainly for AM/FM (which performed flawlessly) with only a passing interest in SW. They offered to buy it off me on the spot, in order to save me the hassle of having to ship it back for replacement!

      So, my PL-660 is now sold, and I have already ordered a new radio from Anon-co, however this time a PL-880. Anna mentioned that those who have personally compared the latest PL-880 revision to earlier ones, have been impressed with improvements in sensitivity, so seeing as how the 880 relies far less on analog tuning components and more on the DSP, I figured my chances of getting a “perfect” one from the factory were better. After looking at photos online of how clean, tidy and well designed the insides of a PL-880 are, and the seriously cool speaker design it has that patently sounds amazing, well that won me over. I’ll live with the lack of a decent sync-lock and air-band. My two other radios have the air-band end of things nicely covered anyway.

      Also, I was carefully looking at photos of several circuit board revisions of the PL-880 and for example, comparing a rev.10 board to a rev.6, the newer one actually has significantly more components on the main board in a few areas, so more than just firmware changes have been made to the PL-880 over the years. Okay, enough off-topic chatter, sorry!

      Anyway, thanks for reading and pardon the long, overly detailed comment! Hopefully this explains my sleuthing (and it probably does so in way too much detail, as is the norm for me, haha)…

      1. Thomas Post author

        Hi, Mike,

        No worries! You’ve done a fine job explaining the calibration process and that has helped a number of PL-660 owners. Small revisions to the PL-660 are likely done every year with various production runs. The PL-880, for example, has a long list of “hidden features” but not all work with each production run.

        Thanks for your detailed comment!


      2. Rob

        Thanks Mike. Even though it doesn’t work for either of my 660’s, I do appreciate the research you’re putting into this as well as how you’re spreading the word. If nothing else, you’ve encouraged me to experiment with my radios and try to find easter egg functions. So far nothing cool, but I’ve only just started. Anyway, thanks again and keep posting.

      3. Paul Kowalski c/o Opis at Tierra Pines

        I really think Tecsun only hurt themselves with all of the oops! afterthought engineering, My life is confined to a nursing home situation and having been an avid SWL/AM DXer, I read reviews and dreamt, ( as a kid does) til I had enough saved up to pop for the 660. I was immediately dismayed by the 5khz drop on AM wide, and though the un-modulated SSB signals came in strong , when properly modulated they were pittyfully weak.I sometimes like to go U or LSB for hard splits. This radio if properly aligned is capable of this .I used a 30 foot wire for the antenna early PM in Florida. You would think that a company who mostly serves their populace where Shortwave is still much needed and then trying to reach enthusiasts worldwide would at least keep us up to date as to how to overcome their mistakes. Just saying…Paul


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