I’m probably more of a listener than a ham. Many of my antennas are dedicated to listening, not transmitting. Receivers outnumber transmitters by a factor of 2. In spite of modern technologies such as satellite and the Internet, listening to shortwave stations is alive and kicking. While it is great to sit behind a professional desktop receiver connected to excellent outdoor antennas, I don’t always want to spend a large part of the day in the shack.
As my old Aiwa SW portable started to die, I went online to check out the current breeds of portable SW radios. One of the brands I ran into, was Tecsun. The models were so cheap that I could buy a truckload of them and still keep some of the the money I reserved for replacing the Aiwa. After reading (sometimes raving) reviews elsewhere, I ordered three models: the PL-310, the PL-390 and the PL-660. This is the first review in the Tecsun series and covers the cheapest of the lot, the PL-310. I bought mine here.
In the box:
The radio, three rechargeable batteries, soft pouch, earphones, USB charger / power supply. Note: other sellers will ship an external wire antenna instead of a USB charger. Compare the extras each seller offers before buying.
Look & Feel
Measuring only 141(W) X 87(H) X 30(D) mm, this radio will slide into your pocket easily. It is thoughtfully designed, beautiful even, and all the buttons and knobs are exactly in the right place. The amber LCD gives more information than you can dream of: frequency, time, bandwidth, signal strength (in dBµ!), signal-to-noise ratio, temperature (in Celsius or Fahrenheit), battery type, charge indicator, battery level, and the time you want the alarm to go off. The LCD illumination can either be temporary or continuous, an option I never saw before.
At the right side of the radio you will find the tuning and the volume knobs. Both are driving opto couplers, so no crackling pots to worry about. At the left side you will find two 3.5mm connections for a stereo headphone and an external antenna. There’a also a USB connector present, which can only be used to power the radio and/or charge the three NiMH AA cells this radio uses. The type of batteries (standard or rechargeable) can be selected from the front panel. This will not only prevent problems, but will also display the right battery level.
The PL-310 is designed around the Silicon Labs Si4734 chip, which basically is a complete DSP receiver in one small package. All Tecsun had to do was to link it to an audio amplifier, buttons and knobs, a display and such and voilá, one working radio! Brilliant. For more specs you can go to the end of this post and download the manual.
The frequency range is as follows: LW: 153 – 513 KHz, MW: 520 – 1710 KHz, SW: 2300 – 21950 KHz, FM: 64 – 108 MHz. The desired MW spacing, 9 or 10 KHz, is user selectable. When set at 10 KHz, which is the norm in the USA, the temperature will be automatically displayed in Fahrenheit instead of Celsius. The integrated DSP is nothing short of amazing. When listening to SW stations, the bandwidth can be set to 6, 4, 3, 2 or 1 KHz. As this is not an audio DSP but a ‘real’ IF DSP, this thing really works. Splatter and such can be filtered out with ease, and easily defeats some of the desktop receivers I own.
Tecsun offers more than one way of tuning. One of them is, of course, tuning manually. The second option is entering a frequency by using the keypad. The third way is to let the Tecsun itself find all the stations. This system, dubbed ATS (Automatic Tuning System), will find all stations within the selected band and store them into memory. After scanning, the tuning knob will enable you to quickly switch from station to station. Similar systems in other radios often failed miserably, as they couldn’t distinguish noise from real signals. Tecsun got it right this time though, and it’s a blessing when listening to shortwave. Just after the hour, when stations come and go, I let the Tecsun scan again, after which the old memory contents are overwritten with active stations.
Something to get used to is the way Tecsun implemented manual tuning. When you rotate the tuning knob fast, the radio will skip frequencies by the standard channel spacing (e.g. 9 KHz on MW, 5 KHz on SW). When rotating slowly, the radio will tune one KHz at the time. It proved to be very challenging to get the rotation speed just right.
Performance LW, MW
When you buy this radio, you will quickly discover that LW is disabled by default. This seems odd, but as it turns out there’s a reason for that: on LW this radio is as deaf as a post. Even a reasonably strong station such as the BBC (198 KHz) is hardly noticeable. As the external antenna input only serves FM and SW, connecting a long wire won’t help. On MW the performance is quite good though. Sensitivity is above average, and the selectivity is excellent. AM 747, the strongest MW transmitter here, and located very close to me, didn’t manage to overload the receiver. Note: the to-be-reviewed-later Tecsun PL-660 did collapse completely.
Performance FM, SW
On FM, this radio is excellent. Not much else to tell here. Period. On SW, especially with an external wire antenna connected to the radio, the performance is much better than one would expect from a small package like this. Only one thing is slightly annoying: the hard coded (and sometimes completely wrong) frequency range of SW bands. 41 meters, for example, starts at 7.1MHz instead of 7.2Mhz (in effect since March 29, 2009). Bottom line: tuning manually is a must now and then. Many stations transmit outside these outdated and limited ranges embedded in the Silicon Labs chip.
The audio quality is a pleasant surprise. You can turn up the volume without any distortion, and the frequency spectrum is better than any other similar sized radio I ever owned. Great stereo sound on FM too, when using a headphone.
For less than $45, you get an amazing piece of technology; the price/performance ratio is off the scale. A nice touch is the inclusion of the 4 meters band, which is already available to hams in some countries. The Tecsun PL-310 is not perfect though. The radio is completely deaf on LW, uses outdated or limited SW ranges, and manual tuning can be challenging.