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New XHDATA D-109 Portable-- Tech Report & Loopstick Transplant
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Based on very favorable reports from Les and others I decided to order several new XHDATA D-109 models for testing and experiments, despite the fact that there is currently no North American supply source. The model is only available from China, with the current lowest price (including shipping) of $39.99 from the eBay vendor "liulituan2014."
Like Les, my impression is that this LW-AM-FM-SW portable delivers a lot of performance for the price. The model has the full range of DSP filtering choices from the internal Silicon Labs' Si4734 DSP chip, and in combination with a reasonably powerful audio amp, the superb 5 watt speaker really makes DXing a pleasure, especially in noisy environments. The radio has Bluetooth and MP3 playback capability, and the relatively powerful speaker enhances the value of these additional features. The stock 70mm loopstick does a reasonable job in tracking down AM-DX stations in comparison with its competition (Radiwow R-108, Tecsun PL-330, etc.), although there is no SSB capability like in the XHDATA D-808 and Tecsun PL-330 models. Overall the stock model does a great job for the price, especially considering the powerful battery, the Bluetooth and MP3 playback capability (with relatively high fidelity audio) and competitive AM, FM and Shortwave DXing performance.
Les had asked specifically about an enhanced loopstick for this model, and of course I was highly motivated to try such an experiment. Upon disassembly I noticed that the stock loopstick was in a strange position at the bottom of the cabinet-- and as far away as possible from the digital display. Usually, when a manufacturer does this it is for a good reason-- the digital display noise would otherwise interfere with the loopstick's reception. In the D-109's case the wide separation of the two components does allow AM-DX reception without digital display noise (unless the user touches his palm to the display), but mounting an enhanced loopstick at the bottom of the cabinet just wouldn't work. I went ahead and did the enhanced loopstick transplant in the D-109 anyway, which was a little trickier than the same procedure in the XHDATA D-808 because the R-109 really isn't engineered for easy disassembly. Upon mounting the enhanced 7.5 inch loopstick in the usual position (see photo) my apprehensions were confirmed when moderate digital noise showed up on all frequencies from 530-1700 kHz. As expected the enhanced loopstick did provide a tremendous boost in the R-109's AM-DXing sensitivity, but the digital hash issue was unacceptable, in my opinion. Most other Ultralight and portable models do not have this digital hash problem, and are much better candidates for an enhanced loopstick transplant.
Since I had already done the D-109 loopstick transplant I wanted to finish up with a hot-performing AM-DX model which was totally free of any digital hash. The only solution was to relocate the enhanced loopstick farther away from the digital display on the left side of the orange frame, as shown in the photo. This antenna position allowed the R-109 to chase AM-DX with superb sensitivity and noise-free reception, making it fully equal in performance to a "Supercharged" XHDATA D-808 model. Although the side-mounted loopstick is less than optimum for aesthetic and other reasons, it does transform this R-109 model into a paragon of AM-DXing prowess.
Best of DX,
Gary DeBock (in Puyallup, WA, USA)
Ex-Navy Sonar Technician
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