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One for the radio amateurs: a first look by ROSS TESTER The G90: A High Spec, SDR QRP HF 12V Amateur Transceiver Best known for their range of quality radio receivers, Tecsun Radios Australia have recently expanded their product line-up with a compact HF Amateur Radio Transceiver from China. With an extensive list of features and a commendably low price, it's enough to make amateur operators take notice! F rom the age of 16 right through to my early-50s I held an amateur radio licence (first the old "Z" call and later a “K” call). But I found I was going on air less and less, to the point where I considered licence renewal an expense I couldn't justify. But if this new transceiver had been around at the time, I might have reconsidered that! Then again, it was not possible for this to be around back then – SDR (software defined radio) was yet to be invented and devices using SDR were therefore non-existent. We're looking at the Xiegu G90, which Tecsun Radios Australia have recently added to their range. They have “dipped their toe in the water”, so to speak, by gradually expanding into other communications equipment. While they are well aware that amateur radio is a strictly limited market, director Garry Cratt believes it is large enough to justify this expansion – particularly if they can offer quality product at a very realistic price. The G90, made in China, fits both of these criteria very nicely. Tecsun Radios Australia carried out extensive research into both the manufacturer and the transceiver itself after being offered distribution rights for Australia. With glowing (independent) reports from amateurs in countries where the G90 is already available, they decided to take up the offer. Incidentally, we should note that we have not used this transceiver on air (for the reason above!) but have relied on 82 Silicon Chip reports from licenced amateurs in our local amateur radio club for their reports. And they were quite enthusiastic! About SDR Software-defined radio (SDR) takes avantage of the capabilities of today's microprocessors to give features and performance that were only dreamed about in decades past. Many of the functions which SDR takes on were originally implemented in hardware – often complicated, intricate hardware – which of course came at a cost. With (usually) embedded processors undertaking all, or most, of the digital signal processing within the radio, the cost of high performance receivers, transmitters and transceivers has fallen dramatically. The SDR software performs all of the demodulation, filtering (both radio frequency and audio frequency) and signal enhancement (eg, equalisation). In the case of the Xiegu G90, the 24-bit data size and 48kHz sampling results in excellent performance and is highly configurable. The G90 The first thing you notice about this transceiver is its size – just 120w x 45h x 210d (mm). But in this small package is a full-featured transceiver covering the entire band from 0.5 to 30MHz (receive), with all HF amateur bands Australia’s electronics magazine siliconchip.com.au programmed in for transmit (10m to 160m inclusive) in AM, SSB and CW modes, with FM available as an option. What's more, it also includes an inbuilt antenna tuner so if you're away from home, you can use a random length of antenna wire (hoisted up a tree, or over a hotel balcony, for example) and the G90 will match into that with an SWR of 1.2:1 or better (many users report a solid 1:1). You'll also notice the front panel with its 1.8-inch colour screen, which has a ±24kHz bandwidth fast-scan spectrum display with waterfall. And there's also the oversize microphone, with 25 push-buttons for control, along with the standard PTT. What you won't notice, until you start reading the documentation and/or using it, is that it offers a transmit power of up to 20W (1W steps) in SSB/CW/FM modes and 5W in AM. Receive sensitivity is excellent at 0.25µV <at> 12dB SINAD. There are two independent VFOs with each capable of different frequencies and different modes. In SPL (split) mode, you can also have split transceiving operation (eg, VFO A for receive, VFO B for transmit). Operating frequencies can be direct-entered via the microphone keypad or “dialled up” using the front panel knob. In the latter case you can also select steps (using the same knob): 100Hz, 1kHz and 10kHz. The transceiver operates from (nominal) 12V DC (actual 10.5-16.5V) but you'll need a fairly beefy supply – at 20W out, it will draw about 8A (did someone mention mobile/ car battery?). Receive, as you would expect, is much lower at about 500-750mA. You probably also won't have noticed that the radio and its display unit can be separated, making for a versatile mounting arrangement. Conclusion Consistent with our earlier statement that we weren't able to fire the G90 up in anger, we can only go on the many favourable comments we've seen online (Google Xiegu G90) – there isn't one post which gives it a less than 4 out of 5 Features: • • • • • • • • • • • • • • • • • • • • • High-performance front end narrowband ESC preselector Covers the frequency range of 0.5~30MHz (receive) Covers all Australian HF amateur bands Three working modes; SSB/CW/AM; FM optional Built-in wide-range automatic antenna tuner 1.8-inch high brightness colour TFT LCD screen ±24k bandwidth spectrum display, waterfall display Software defined narrowband filter (CW mode: 50Hz) Detachable display unit RF power output: 1-20W (in 1W increments) Sensitivity: typically 0.25µV <at> 12db SINAD Adjacent channel suppression: 60dB Rx dynamic range: 90dB Spurious suppression: better than 50dB Sideband suppression: better than 55dB Audio output power: 0.5W into 4Ω Operating temperature range: 0-55°C Operating voltage: 10.5-16.5V DC (12V nominal) Current consumption: Rx 750mA, Tx 8A max Size: 120 x 45 x 210mm Weight: 1.85kg and, indeed, most give it 5 out of 5. And the members of the local radio club who have used it on air had nothing but praise. One comment we heard was that, despite the huge range of controls on this transceiver, the learning curve was virtually non-existent. “You take it out of the box, plug in an antenna and power supply and you're ready to go.” It also earned top marks for ease of use, for receive quality and for transmit quality reported back from club member's contacts. Yes, it is QRP (low power, for those who don't know radiospeak!). But there's an old adage in amateur radio: you can work the world with five watts . . . It becomes more of a challenge for avid amateur operators! Warranty and service The G90 Transceiver is guaranteed for 12 months from date of purchase. Warranty and any out-of-warranty service work will be undertaken by Tecsun Radios Australia in their fullyequipped service centre in Sydney, although they do reserve the right to send units back to the manufacturer for more specialised work, if required. Naturally, any units which have had hardware or firmware modifications are not covered by warranty. Price Aha! We knew you'd be asking that . . . The Xiegu G90, Tecsun Radios Australia (cat no Q5000), has a recommended retail price of $740.00, including GST and freight within Australia. Overseas customers should email Tecsun Radios Australia for a quotation for freight to their location. The G90 sports a very nice 1.8-inch TFT display which not only gives you both VFO frequencies, modes, receive "S" and even the antenna SWR via the inbuilt antenna matcher, it also has a fast-scan spectrum analyser with waterfall display. siliconchip.com.au More info? Log onto www.tecsunradios.com.au/store/product/ xiegu-g90-transceiver/ for more detailed specifications and user reports. There's also a range of accessories available but everything to get you going is supplied in the box! SC Australia’s electronics magazine April 2020  83