Many thanks to SWLing Post contributor, Andy, who writes:
I wonder if any of your readers has noticed anything with later model PL-660s.
My old PL-660 met with an accident recently (purchased about 2015?).
I bought a new one and was disappointed by what appears to be
a difference with the narrow and wide filter.
My old version seemed to work well, with 3kHz and about 6kHz
widths as one would expect.
The new one is a disaster, you seem to get 3kHz and 18kHz widths roughly
resulting in poor performance, especially on local AM stations.
It’s like the same station appears twice.
Also the filter is not symmetrical.
It’s all on the HF side of the signal and it’s awful.
The older model centred the correct bandwidths properly.
I’ve tried to do a bit of research, not much really but the little info that I have found appears to show that others have the same problem.
It makes the use of the wide filter in any mode useless.
I’m gonna send mine back.
73 de Andy G0FTD
Thanks for sharing this, Andy. I haven’t purchased a PL-660 in ages–in fact, I gave mine to a friend interested in shortwave a few years ago. I still use my PL-680 regularly. I suppose it’s possible you might have received a lemon; this isn’t uncommon as quality control varies with production batches.
SWLing Post readers: If you have noticed these symptoms–especially an abnormally wide filter width–with your late model PL-660, please comment.
I bought mine few days back…no issues regarding reception.I have a Tecsun s2000 so it’s easier for me to compare.Overall at this price range I am satisfied.I am using a loop antenna too for medium wave,with that I am able to receive stations in Australia even Alaska. I guess my set is good,well calibrated.There is also calibration option if offset somehow.Overall I am satisfied.
I wish I could check my 660 to see what it does, but about 6 months ago, it just stopped working. That is, it won’t turn on, at all. I’ve changed batteries, plugged it into an AC outlet, but nothing, dead. Any thoughts, suggestions, etc., would be appreciated.
Hi blues dude. I had the same issue some time ago. Turned out to be a dead super capacitor. I replaced the component and everything went back to normal. Check this link:
Hope it helps. Best regards.
I have a 660 purchased around September, 2018.
The WIDE filter is too wide and off-center(?), I have to de-tune downward as much as 10kHz before the WIDE sounds better, but it never, ever sounds good.
The Sync is hard to tune in, because first I have to Zero-beat, then try all 3 options under Sync, and most of the time I get the Woop-Woop sound unless I’m on a REALLY STRONG Signal, which doesn’t need to be Synced in the first place.
The frequency calibration is “close enough”. No complaints there. I did the calibration several times, but it never sticks once you change off by even 1kHz.
Another thing I don’t like is that weird 3+1 battery arrangement. It messes with my OCD.
It should be 2+2 or 4-in-a-row, and that would make the radio more bottom heavy and more stable and less needing that 2nd kickstand.
Overall, I like the 660 as a good rig for listening to 1 station for a long, long time. It’s got great audio, assuming you feed it a good signal. Its a good rig to keep in the garage or at the office, to keep up with the news and weather, or follow a ballgame at lunch. It does a good job on SWL with really strong stations. But its not that great at DX hunting or bringing the weak ones out of the mud.
I don’t think I’d buy another 660. There are too many other great radios out there in this price range, in fact quite a few options that perform better for less money.
Are the filters in these accomplished in hardware or software? I’ve seen a number of people mentioning that their recent Eton 750s have a similar issue with too wide of bandwidth. If this is done in hardware I’m wondering if they are only able to source inferior parts at this time?
> Are the filters in these accomplished in hardware or software?
Hardware; the PL-6xx use ceramic filters.
The larger quality manufacturers (e.g. Murata, Taiyo Yuden, etc.) mostly stopped making / severely reduced their range of lower-frequency ceramic filters a decade or two (or more) ago. All that’s available since then have either been from the better Chinese manufacturers – and even those started getting scarcer pre-Covid – or cheap random-branded near-junk where you have to sort through them to find suitable ones.
Everybody making portable radios using hardware filters is in the same boat. Simple reason is just that there’s a lot less demand for 455kHz – or even 10.7MHz – filters/resonators these days.
(At a guess, OP’s new radio has a faulty wide filter or switching diode(s) – the way these are switched in the PL-6xx means there is some interaction between the two that shifts the filter bandpass slightly. That’s definitely a returnable fault.)
Tecsun PL-660 I have is a very late model
and it works well but compared to the
XHDATA D-808 it’s receiver at least on SSB isn’t as good.
I’ve also done tests with Belka DX and DSP,
the 808 out performs them too, however
for sheer portability the Belka wins hands down.
These PL-660s seem to be notorious for not having the IF tuned properly. Mine indicates 1 kHz higher than the actual station frequency when it’s tuned for best response.
If I tune the radio so that it indicates the right frequency, it’s actually off frequency, and sounds like it, AND the filter bandwidth seems asymmetrical (it’s not, the radio is just tuned off frequency).
Maybe we should compile a list of firmware versions that have (or not) issues ?
Hold the airband button in for about 4 seconds.
Display icons all light up and then it will reveal the firmware version.
My bad one 6622.
Faults found –
1) Awful wide filter. Appears to simple create a bandwidth of about 18Khz extending from the
carrier frequency upwards. Make no difference to anything below the carrier freq. Useless.
Older version did it properly.
2) BFO knob when tuned above the carrier has a some dead travel. The result is the RX simply having
no output. It’s as if the BFO has been completely tuned outside the IF filter bandwidth. Tuned lower
it’s fine and smooth with no audio drop out.
2b) Unequal BFO frequency offsets. Worst case just about makes 1khz on the high side.
3) USB and the AM USB sync detector had way too much HF response. USB sounded noisy and tinny.
LSB sounded good though.
My older circa 2015 version did not have these issues an worked smoothly and in accordance with
what you would expect with any other receiver.
But there were also some good points noticed.
A) Improved LF audio response on broadcast signals, especially noticeable on FM. Sounds as classy
as my PL880, which has the best broadcast audio quality of any modern rx.
B) Signal meter on FM broadcast appeared to have a bit more dynamic range.
C) Airband AM audio sounded a bit better and the the rx sounded less noisy.
But oh boy, that wide filter bug is a total disaster. There’s no excuse for it.
73 de Andy
Drat, forgot to add, SW AM readout was 3Khz too high as well on my recent mode firmware 6622.
I’ve bought 3 of these, in 2011, circa 2016, and 2020. The first and last ones perform fine. The 2016 one is always off-frequency (yes, I tried the recalibration procedure here at this site) and something is screwy with the detector – it just always sound fuzzy. Too bad I didn’t diagnose that until the Amazon return period had expired.
I hate to see trouble popping up with the 660. It’s one of the few radios at this price point where both SSB and sync both work.
My less than a week old example has the same issue. That, along with frequency calibration that’s off from 2-3 kHz, makes my example unlistenable.
They are issuing a full refund- didn’t even offer to send a replacement unit.
I think they know they have a serious QC issue lately.
I have experienced exactly the same issues with the PL-660. I tried two different recent production radios and both experienced the same issue with regards to excessively wide filter widths on the wide filter as well as filter asymmetry. This was in addition to other issues exhibited such as a wandering heterodyne on the AM band that made reception of certain AM frequencies impossible.
I also had a PL-660 in the past and it did not have any such filtering issues. However, before I sold it it did start having issues with a wandering heterodyne on the HF bands though it was nowhere near as strong as the heterodyne in the one PL-660 recent production receiver that I tested.
After going through two separate PL-660’s on a return basis I ended up purchasing a PL-330 for something compact to bring with me while traveling. At least with this radio the filtering works as advertised.