Tecsun PL660 and PL880

The Tecsun PL880

First up is the Tecsun PL880, a dual conversion superhet with a 3rd IF which is actually a DSP audio stage. The PL880 covers from 100Khz - 30Mhz, in 10Hz steps. AM, USB and LSB are selectable modes. CW is catered for through the use of the SSB modes. In fact CW is catered for extremely well because of the wide range of selectable filters available, right down to 500Hz. Filtering from 9Khz down to 500Hz is available and is very effective in practice. This is done by DSP. The receiver has an unusual S-Meter, that is calibrated in dbuv (db above a microvolt, and SINAD).

These two figures are displayed at the same time and are effective on all modes. There are no traditional s-meter units on this receiver. A front panel button can select between s-meter or clock. An external antenna socket is available for the 1.7Mhz-30Mhz with selectable attenuator. It is also the only receiver I have seen in modern times that includes a fixed LINE OUT socket for recording in addition to an earphone output socket. VFO and keypad entry is available.

The receiver does NOT use a traditional set of batteries or cells, but instead uses a single 3.7v 18650 lithium ion cell. Several years ago I would have said that this was a turn off, But having now used these cells in my own home brew projects, and discovered that these cells are quite widely available, and the chargers, I am now completely at ease with them.

I purchased my PL880 from Anon-Co in Hong Kong online. They are a trusted supplier and deliver within 6 working days, where the postman just handed me my parcel and wished me a good morning. For safety reasons, there is no 18650 cell shipped with the receiver. The receiver can also be powered from a USB cable. I was pleased to see that a USB PSU could be used, and that Tecsun have used one of the sturdier types of connector, that should give long life.

A well packed branded box reveals a great package inside. The first thing that hits you is the high quality carry case for the receiver. There is a pair of good quality ear buds, an external wire antenna, and a world amateur radio prefix map of the world. I seem to recall I got a Yaesu version that looked very similar some years ago. Nice touch.

So how does the receiver perform in practice ? Very well indeed. Sensitivity is good throughout the frequency range using only the telescopic whip. I was able to monitor the local Kent and Essex AMPSNET quite well on AM. The usual VOLMET signals around 5Mhz were heard with complete ease. Using the receiver on 20m CW was a dream come true. On 18MHz I was hearing several ZP (Paraguay) stations loudly on SSB.

Propagation was pretty dead above 20Mhz, but I used the receiver on 28Mhz to hear some weak ground wave beacon stations that I use as a reference point, and they appeared almost as good as my FT817. Using the external wire antenna of only a few metres long improved the sensitivity quite a lot with no overloading on all bands. I have not been able to determine the antenna input impedance of the external antenna socket. It does not appear to be 50 ohms, and maybe 600 ohms judging by previously seen Tecsun models.

One thing that strikes me with this receiver is the audio quality, it's amazing ! This little rig sounds more like a pair of KT88's and an 18 inch cabinet speaker. AM broadcasts have never sounded so good. My only slight criticism of the receiver is the stability on 28MHz. When you squeeze the plastic casing of the receiver there is a small frequency change heard. Well it's to be expected if using a plastic case I suppose. Otherwise the receiver is completely stable in use and present no real problem. I could not find any spurious responses or birdies throughout the whole HF range. However it is not known what the input impedance is of the PL880.

A crude sensitivity test using a Tiny SA Ultra as a signal generator shows that -110dbm in SSB mode is detectable at the S1 level. Atmospheric noise at 3Mhz is -100dbm , or -120dbm at 28Mhz. Not a bad result for a basic portable receiver via the telescopic antenna. And S9 signal level (-73dbm) shows 27db/uv on the PL880 signal meter. For some fun I checked the FM sensitivity at being -85dbm for a readable signals, and by -90dbm there was nothing at all. The measurement method was just directly inject the test signal into the retracted telescopic whip on the receiver whilst in the mono mode. On FM broadcast this is quite acceptable but I have seen slightly hotter receivers that can achive -100dbm.

Anyone interested in calculating galactic noise floor can use my spreadsheet. Galactic noise is the  the lowest level that a receiver should be capable of receiving. But of course local QRM etc makes things worse. So if a receiver can detect down to Galactic noise levels then it's the best you can do. . Anything else starts to become a waste of time,

This receiver also covers 64-108Mhz FM making it a great band monitor for the OIRT band and east European / Russian FM broadcasts when sporadic E is present. Unusually the frequency steps are 10Khz which makes searching very easy. We 70Mhz band users often hear a broadcast on 70.475Mhz when the band is open. There are of course many others outside the 4m band. A good broadcast frequency listing to assist with this activity can be found at the end of this article.

The Tecsun PL660.

Next up is the PL660, slightly smaller in size than the PL880 and is supplied with a soft carry case, good quality ear buds, extra wire antenna and a DC charger. This receiver covers 100Khz-30Mhz with selectable USB/LSB/AM modes. There is a simple narrow / wide button to select bandwidth for these modes. The narrow setting is not narrow enough for CW though but works very well for SSB and AM. FM broadcast from 76-108MHz as well as VHF AM airband. Traditional VFO control and keypad frequency entry is available. The S Meter is a simple 0-5 units indicator with active intermediate steps between each whole integer. It works reasonably well except on FM broadcast where it seems to lack dynamic range. Below - PL660 on the left and PL880 on the right.

The receiver uses traditional AA cells (three of them) and can be charged from the supplied 6v DC PSU. (Positive earth connector so watch out!)

Receive performance is not much different from the PL880. It works well on it’s own telescopic whip antenna except below about 4Mhz where a few metres of wire can be used to increase performance. Adding a simple wire antenna didn’t appear to give any problems with intermod etc. In fact, I have more problems with my IC-706 and intermod than these portables ! There is a 3.5mm jack socket for external antenna use. Like the PL880, I was unable to determine what the input impedance was. Over the last four years I have used this set many times on 80/40/30/20m and never feel that I am missing out on signals. QRP signals are heard with ease. Broadcast FM sensitivity seemed excellent, medium wave being very good and long wave seemed OK. Airband AM seems good, but remember that there is no scanning or memories available, manual tuning only.

The PL660 must be one of the most frequency stable receivers I have ever used. It stays rock solid from switch on, and passes the “squeeze test” where I squeeze the plastic case, flex PCB’s and alter screening effects. Another bonus in this receiver is the AM synchronous detector mode. This has to be the best in history and will please broadcast listeners, or anyone listening in to the AM nets on about 3605Khz or 3715Khz here in UK/Europe. The receiver was free of any spurious responses or birdies throughout it’s range.

Using these receivers – in practice.

I tend to be biased towards /P operation, often from a beach or outdoor space. As such I have used them quite well just as a stand alone receiver alongside a small transmitter, using only a telescopic whip antenna or a few extra metres of wire thrown up a tree or pole to increase sensitivity (more than adequate). In fact even from a quiet beach location I can use the attenuator to reduce natural atmospheric noise, proving that the receiver has enough sensitivity from about 5Mhz to 20Mhz just on a small telescopic whip.

You could quite easily use these receivers to form part of a simple ham radio station alongside a companion transmitter.

Later models appear to have hidden menu access for software frequency alignment. Please review the docs that's I've placed in my Google drive in the link provided below. It appears that later models can be identified by the grey rubber feet on the bottom of the case on a PL660, though I can't guarantee that.

Buyers guide. [UPDATED 2022]

The PL660 should cost about in Sterling £145 delivered, and the PL880 should be about £175 delivered from online sellers.  Prices before the global tax changes and world events where once half of of this ! But now some bad news. It appears that some recent models of the PL660 have got a  few problems. The story so far is that my original PL660 had an unfortunate accident. I purchased a replacement almost immediately. But there was a big problem. The filter bandwidths were crap. I tried for example tuning to BBC Radio 5 on 909Khz and could hear it clearly on the next channel !  Tecsun had doubled the IF bandwidth of both the narrow and wide filters ! I do recall a post on swling.com that mentioned that Tecsun had redefined what a filter bandwidth was. For example a 6Khz filter now means 6Khz either side of the carrir frequency and not the traditional 6Khz total, e.g. 3Khz from the carrier frequency - DOH ! And the BFO doesn't work properly. If you advance the control clockwise then before it reaches the end of it's travel the RX audio dies. It's like the Carrier Insertion Oscillator has been tuned right out of the IF filter bandwidth. Bad ! I tried two of them and they did not work like my original PL660. I sent both replacements back in disgust.

HOT TIP. After some 6 years of trouble free operation I switched my PL880 on and all the LW/MW/SW was dead. FM was perfect. I used the reset button but that didn't work. I took out the battery until the clock died. Still no good. Then I took out the 18650 cell and left it for about 4 hours before reinserting it. Voila - it returned to life perfectly. But what caused this ? I needed to do some longer term observations and tests. It appers to be that under certain conditions when I became charged with static electricity and then handled the receiver, that I then sent some charge probably via the telescopic antenna, enough to cause some CPU confusion. I was wearing what I called "safety boots" at the time, and became insulated from ground potential several times. It's something also worth considering when handling equipment like Nano VNA's and Spectrum Analysers. UPDATE - June 2024. The pull out the battery method appeared to work well, no problems have been encountered after many months of a reset operation using this method.

(1) www.anon-co.com [Tecsun dealer in Hong Kong.Takes Paypal and very reliable]

(2) http://www.fmlist.org/scanner.php?mode=1&area=1&MHz=70 [Freq database]

(3) https://swling.com/blog [Good SWL info and receiver reviews]

(4) Handbooks and data https://drive.google.com/drive/folders/1tlFeEoPYibHsfv1OWkDs0xGj_6rvYFv2