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Review by Ross Tester All singing, All dancing . . . Tecsun’s S-2000 Multiband Radio After seeing the reader review of the tiny Tecsun PL365 Multiband Radio in the June issue of SILICON CHIP, Tecsun Radios Australia asked us if we’d like to review the “flagship” Tecsun, the S-2000 Desktop Radio. Knowing how much our readers are still interested in performance radios (you tell us!), of course we said YES! D espite the growth of internet radio, where you can “tune in” to virtually any radio station in the world on your computer in crystal clarity, the somewhat dying “art” of using a communications receiver to actually resolve faint, almost non-existent radio signals from the other side of the world still has a fascination for many. Of course, with city living, a lot of readers are often compromised by their surroundings when it comes to erecting “decent” antennas but that doesn’t stop them from trying. 88  Silicon Chip But then you need a similarly “decent” receiver. Having grown up in the days of large valve receivers with limited shortwave bands and limited bandspread (absolutely zero bandspread when it came to amateur bands!), I spent countless hours “twiddling the dial”, looking for both long distance AM broadcast stations and overseas shortwave stations – to this end I was forever erecting higher and longer antennas. I even worked out that tuning another receiver close to siliconchip.com.au the one I was listening to would even allow me to listen in to “duck talk” (which I found out much later was SSB and I was “resolving” the signal, albeit crudely!). Fortunately, being a “boy from the bush” with accommodating, if somewhat bemused, neighbours, I had quite an advantage over my city cousins. I recall my last antenna stretched over three backyards and ended secured near the top of what must have been a mile-high poplar tree. OK, I’m exaggerating that just a tad but it was [to a 12-year-old] rooly, rooly high, particularly when I had to climb that tree to place the wire and then [regularly!] to repair breaks. I digress somewhat – just to reinforce the fact that I had enormous listening pleasure with that old valve receiver, logging both commercial and even amateur radio stations on every continent (except Antarctica!). It did wonders for my geography classes at school, too: how many other kids knew that Quito was the capital of Equador? (It was also the home of HCJB, “The Voice of the Andes”). You can imagine my unbridled joy a decade or so later when I managed to get my hands on the (now) venerable Yaesu FRG-7 communications receiver (known affectionately as “The Frog”). Sure, there were many others (does anyone remember the Collins, Heathkit, Hallicrafters, Kenwood, Geloso and so on?) but in Australia, at least, The Frog was The King! To give you some idea of their reputation, even today you can expect to pay over $500 for a good Frog on ebay (if you can find one!). Enter the S-2000 I mention The Frog because this triple-conversion, Wadley-loop receiver really was the yardstick by which all receivers at the time were compared. And it’s not too dissimilar in size to the Tecsun S-2000 – about the same width and height but about double the depth. It was also a LOT heavier – more than double the Tecsun’s weight. And while its performance as a communications receiver is still “right up there”, the amount of features pale into insignificance when you look at today’s PLL (phase-lockedloop) receivers. Like The Frog, the dual-conversion Tecsun S-2000 offers reception up to 30MHz (actually 29.999MHz whereas The Frog was 29.900MHz) but unlike The Frog (which just went low enough to cover the AM broadcast band), it starts at just 100kHz. In addition, the S-2000 also offers the 88-108MHz FM broadcast band (in stereo if you use headphones!) along with the 118-137MHz aircraft band. At left is the external antenna connection panel, offering 50Ω for FM and shortwave and 500Ω for AM and shortwave. Above is the stereo (for FM) line out socket and somewhat unusually, a 455kHz AM IF output socket for an external decoder (eg, DRM). siliconchip.com.au Tecsun S-2000 Performance & Features • Bands: • Sensitivity: MW 522-1620 kHz (9kHz Tuning Step) LW 100-519 kHz SW 1711-29999 kHz AIR 118-137 MHz FM 87-108 MHz (FM stereo via ’phones) LW – less than 3mV/m (S/N 26dB) MW – less than 0.35mV/m (S/N 26dB) SW – less than 18µV (S/N 26dB) SSB – less than 1µV (S/N 10dB) AIR – less than 5µV (S/N 10dB) FM – less than 3µV (S/N 30dB) • Selectivity: Wideband AM (±10kHz) – Greater than 40dB Narrowband AM (±5kHz) – Greater than 60dB • Image Rejection: MW,LW,SW: 55.845MHz (1st IF): Greater than 90dB 455kHz (2nd IF): Greater than 80dB AIR: Greater than 90dB FM: Greater than 60dB • IF Rejection: AM: 55.845MHz (1st IF): Greater than 60dB 455kHz: Greater than 60dB FM: 10.7MHz: Greater than 100dB • AGC: Range wider than 80dB (threshold 12µV) • Dual conversion for LW, MW & SW • Single side band (SSB) with USB & LSB • Auto/manual frequency tuning or station memory tuning or direct frequency key-in function • Auto suning storage (ATS) function for FM / MW & LW (5s pre-listening while auto tuning) • 1000 station memories (100 each for FM, SW, SSB & air band; 50 each for MW & LW; 500 for mixed band) • 24 hour clock and dual alarm clock function (alarm by either radio or buzzer) • Sleep timer function • Extra-long telescopic whip antenna for FM, SW, Air Band. • 360° rotating MW antenna • External or internal FM/MW antenna switch • Antenna attenuation to enhance reception. • Squelch control. • Wide/narrow bandwidth selection • RF gain control. • 455kHz IF output jack (for synchronous detection, DSP demodulator, DRM converter, etc) • High quality built-in 4-inch speaker • Line in socket (can be used as speaker for MP3) • Line out socket (radio broadcast can be transferred to amplifier, recorder, etc) • Power sources: 4 x “D” alkaline batteries 230VAC power 6V DC jack (<at> 350mA maximum) • Dimensions: 372 x 183 x 153mm (w x h x d) • Weight: 2.7kg • Price: $425.00 including GST August 2016  89 I can’t recall how many station memories The Frog offered but the Tecsun has 1000 – yes, one thousand – 100 each for FM, SW, SSB and Air band; 50 each for MW and LW and 500 for mixed band. You can automatically or manually store stations as you find them and sort them later as you wish. OK, let’s stop making comparisons because they aren’t really fair – The Frog was made in the late 1970s/early 1980s and electronics have come a long way since then. Instead, have a look at the Specifications Panel and you’ll see just how advanced the S-2000 really is! OK, what’s it offer? We’ve already looked at the modes of operation and frequencies. What we should add here is that it also has a 455kHz IF AM output socket for other (external) decoders, such as DRM (should we ever see it in Australia – but you can tune in DRM from over the ditch!). It also sports line-out for external amplifiers (300mV, 4.7kΩ), with stereo sockets for FM broadcasts, an 8-32Ω stereo headphone/earphone socket and also an audio line-in. As far as antenna inputs go, along with the inbuilt, rotatable ferrite rod antenna on the top of the set (which we’ll look at shortly) it also has a rather longer than “normal” whip antenna (the specs say 1200mm; we measured 1000mm) for FM and air band. If you want to use an external antenna (and who wouldn’t on a receiver such as this?) you have the choice of 50Ω BNC inputs for FM, air band and SW or 500Ω (long-wire) input for shortwave and AM. A slider switch selects either internal or external antenna. Power is either 230VAC from an inbuilt cord, nicely stored in a compartment at the rear, 6V DC (<at> 350mA) via an external adaptor or 4 x “D” size batteries (preferably alkaline). We’ve seen mention of using 4 x “AA” size but without an adaptor, this would not be practical. In fact, we wouldn’t go this route (even if we could find an adaptor) because the smaller cells would have a significantly shorter life. Controls The Tecsun S-2000 offers so many front panel controls that you could be confused at first but they’re all pretty logical and a couple of hours’ use will have you quite familiar with them. Looking at tuning first, you have the choice of directly inputting frequencies via a keypad (having first selected the band you want), scanning the band via a pair of up or down pushbuttons, or manually tuning via a large knurled knob. And speaking of that knob, it’s very reminiscent of those found on receivers of yore – big enough to make fine tuning easy – about the only thing it doesn’t do is zoom from one end of the dial to the other when given a good spin, like some of those older, heavier tuning knobs used to do! Like most scanning receivers we’ve experienced, it only temporarily stops when it finds a station so if you want to listen in to that one, you have to hit the scanning button once again. (They call it pre-listening). Note that there is no auto-scanning available on SW/SSB [understandable] nor on the AIR band [why not?]. Alongside the direct-entry keypad buttons are further buttons controlling wide/normal bandwidth, AM/USB/LSB, FM mono/stereo and single-press buttons for FM, MW/LW, SW, and air bands. A large (80 x 35mm) LCD screen displays a vast amount 90  Silicon Chip of information: the tuned frequency and the band in use, of course but also detail such as the timer and alarm settings, various modes such as the shortwave (metre) band in use, USB or LSB, FM stereo or mono, narrow or wide bandwidth, battery strength, fast or slow tuning steps and also information about the memories in use. There’s also a bargraph on the left side which shows signal strength. Other controls are the volume, bass and treble knobs on the left (though the bass control doesn’t seem to affect bass so much as volume), while on the right are RF gain, squelch and SSB BFO (beat frequency oscillator) knobs. There’s also a nice big red power button, sleep, antenna attenuation, fast/slow step and reset buttons plus time/ timer/alarm set buttons and one which controls both the dial light and also the snooze function. Finally, an analog signal strength meter displays both “S” units and a 1-5 relative scale. However, we found this a little too small and too deeply recessed to be of much use. That might change with familiarity, of course. Sensitivity and selectivity Apart from the frequency ranges covered, two of the most important specifications for a serious listener are the receiver’s sensitivity – its ability to receive extremely weak stations; and its selectivity – the ability to separate, or resolve, two stations close together on the band, particularly if one is strong and one is weak. The Tecsun S-2000 quotes sensitivity and selectivity figures which are not too bad at all – more than adequate for the vast majority of applications and very good for what amounts to a relatively low cost receiver. (Yes, you can do marginally better, but be prepared to pay a lot more!). In use The first thing you notice about the Tecsun S-2000 – apart from the styling – is its great audio quality, especially on the AM & FM broadcast bands. This is thanks to its large (~100mm) inbuilt speaker. There is a tiny amount of “digital whine” off-station or in very weak stations but I did not find it objectionable. But of course listening to the broadcast bands is not the main reason for buying a receiver of this type. The second point to note is the very low noise floor – it seems to do a great job of lifting DX or weak stations out of the noise. That’s important. Using the inbuilt antennas for shortwave, air band etc is always going to be a compromise – there’s nothing like hooking up an external antenna. Hooking in a long-wire antenna will reveal stations you didn’t know existed. But even if you don’t have the room for a large outside antenna, Tecsun Radios Australia have a couple of indoor or limitedarea options (eg, loop antennas) available to assist you there. If you cannot plug in an external antenna and you’re plagued by interference (either another station or electronic noise), you may find the rotating antenna (on top of the set) is able to null out the noise and give you the station you want. One thing I found (to my delight) was the stability of the radio. SSB, in particular, can often suffer from drift but once tuned in, I didn’t have to nudge the dial once. If you want to listen to a particular station at a particular time, the Tecsun has all the alarm functions you could want. And with audio output, it makes for convenient recording if you wish. siliconchip.com.au However . . . I mentioned its stability a moment ago. While that’s true, it does have one curious “quirk”. Normally, when you start to tune off an AM station, sibilants (the hissing sound on words with an “S” sound) become more and more pronounced until you start losing the signal completely. On most receivers, this starts happening just a few kilohertz off the station frequency. The quirk which I noticed with the Tecsun S-2000 is that this doesn’t tend to happen – in fact, if you tune a few kilohertz off the station frequency, the recovered audio actually sounds better than right on frequency! For example, I tuned to Sydney’s 2GB on 873kHz (AM) via the direct entry (keyboard) method. Fair enough, the audio was more than acceptable. But nudging the tuning dial a little in either direction (eg, 869 or 878kHz) and the audio was even better! No, I have no explanation on either how or why this happens (perhaps it has something to do with the inbuilt filters) . . . but I went online and discovered other reviewers have found exactly the same thing. It’s not a major criticism of the Tecsun S-2000 but, like the bass control which doesn’t seem to affect bass, it’s a criticism nevertheless. The BFO (beat frequency oscillator, used to resolve SSB signals) is not particularly linear in operation; in fact it seems to have much more effect in a clockwise direction (from zero) than in an anti-clockwise direction. I’m not sure that this is not a design “feature” but it is, well, different! Typical of many aircraft-band radios, you really need to be reasonably close to the aircraft or airport, otherwise you’re likely to be disappointed. I didn’t have a tuned air-band antenna to check it out on but I’m sure it would improve things considerably over the built-in telescopic whip antenna. Conclusion It’s a good performer, especially for the money. It’s quite easy to use and should give you countless hours enjoying listening to stations from around the world. Having the extra bands is a real bonus – not everyone wants to sit there for hours with an ear up against the speaker, straining to hear that almost-there shortwave or amateur station. You need to remember that this is NOT a communications receiver in the true sense of the word (and as discussed earlier). It’s a very nice, low cost, LW/AM/shortwave receiver with FM radio and air bands – and lots of “niceties” – thrown in! To do any better at all (and even that’s arguable), you’re going to have to spend a lot more money! For the vast majority of users it will prove not just good but great – in fact, many comments I’ve seen on line suggest it’s an even better performer than many of those sets costing significantly more. While it looks the part, it doesn’t have the weight of communications receivers simply because it has a switch-mode supply. This doesn’t appear to introduce much in the way of digital interference to the receiver, so it’s well shielded. The Tecsun S-2000 retails for $425.00 (inc GST but plus p&p) and is available from Tecsun Radios Australia, Unit 2, 49 Powells Rd, Brookvale NSW 2100; tel (02) 9939 4377. You can check it out, along with the range of accessories available, on their website: www.tecsunradios.com.au SC Radio, Television & Hobbies: the COMPLETE archive on DVD YES! NA MORE THA URY ENT QUARTER C NICS O R T C E OF EL R O T HIS Y! This remarkable collection of PDFs covers every issue of R & H, as it was known from the beginning (April 1939 – price sixpence!) right through to the final edition of R, TV & H in March 1965, before it disappeared forever with the change of name to EA. For the first time ever, complete and in one handy DVD, every article and every issue is covered. If you’re an old timer (or even young timer!) into vintage radio, it doesn’t get much more vintage than this. If you’re a student of history, this archive gives an extraordinary insight into the amazing breakthroughs made in radio and electronics technology following the war years. And speaking of the war years, R & H had some of the best propaganda imaginable! Even if you’re just an electronics dabbler, there’s something here to interest you. • Every issue individually archived, by month and year • Complete with index for each year • A must-have for everyone interested   $ in electronics E xclu si ve t o: SILICON CHIP siliconchip.com.au ONLY 62 00 +$10.00 P&P Order now from www.siliconchip.com.au/Shop/3 or call (02) 9939 3295 and quote your credit card number. August 2016  91