7.5 inch Loopstick Radiwow R-108

Gary DeBock

The Chinese-made Radiwow R-108 is a very compact AM-FM-LW-SW-AIR portable which has recently become available to North American purchasers via eBay, where it is currently offered at various prices (the lowest being $49.98, including free shipping) in listings such as https://www.ebay.com/itm/RADIWOW-R-108-Radio-Digital-AM-FM-Portable-Stereo-LW-SW-AIR-Band-LCD-fm-Receiver/173793532305?hash=item2876e6d991:g:esMAAOSw1YRcZTng

     Since it is obviously an Ultralight-sized radio and a DSP-enhanced design with multiple selectivity options, four of the R-108 models were purchased for performance tests, technical investigation, quality control checks and comparison with similar models. The Radiwow R-108 is manufactured by the same company that builds the XHDATA D-808, so the styling is very similar, with dark grey cabinets, orange colored power controls and company logos, and lithium-ion rechargeable batteries. And like with the D-808, you will search the owner's manual in vain for any type of manufacturer's warranty. Chinese companies typically don't offer them in their domestic market, and Radiwow isn't offering them on either the R-108 or D-808. 

     This Chinese company certainly draws a lot of "inspiration" (to use a very generous term) from the C.Crane Skywave model (manufactured in the same Chinese city, Shenzhen, at the Redsun factories). Whereas the company's reverse engineers started their D-808 model with wholesale design appropriation of the Skywave SSB's technical innovations, the new R-108 matches the CC Skywave exactly in height, length and width, as well as in the location of the company logo, speaker, wrist strap, display, keypad, power control, tuning knob and volume control. As a crowning touch, the company's reverse engineers ensured that the R-108's screened-on tuning and volume control legends match those of the CC Skywave exactly.

     Since only one of the R-108 test models has arrived here so far I haven't yet done a full technical disassembly, although to its credit the R-108 does have good shielding of the DSP chip, avoiding the irritating digital whine which occurs in recent (post 2012) Tecsun PL-310ET and PL-380 models when the display is grasped. The R-108 also seems to correct the internal heterodyne generation issues of the Tecsun Si4734 DSP chip models (PL-310ET, PL-380 etc.), although my first R-108 test model did suffer from a new digital issue-- intermittent, nasty oscillations at the extreme high end of the AM band (1650-1700 kHz). Whether this a congenital issue or not will be determined when the remaining three R-108 models arrive, but previous reviews of this model have mentioned uneven quality control.

     The reason why I mentioned that my first R-108 model "did" suffer from high band oscillations is because when I replaced the midget 2.75 inch (70mm) stock loopstick with a 7.5 inch Amidon Type 61 transplant, the oscillation problem not only disappeared completely, but the "Supercharged" R-108 became a tiny little terror in AM band sensitivity, fully competitive with the "Supercharged" D-808, Skywave, and Skywave SSB models. Because the R-108 can be purchased for only $49.98 (shipped to North America) and the 7.5" loopstick modification can be done for $35 in parts, a DXer can have an outstanding "Supercharged" AM-DXing compact portable for travel and casual DXing-- all for under $100 U.S.

     The 7.5 inch loopstick transplant procedure on the R-108 is fairly straightforward, although it is slightly more technical than the equivalent Tecsun PL-380 and XHDATA D-808 procedures. The 250/46 Litz wire leads must be routed through the empty wrist strap hole, which is on the opposite cabinet side from the RF circuit board. Despite this, once the cabinet sides are placed in the appropriate position (as shown in photos which will be uploaded to the Ultralight Experimenters site) the transplant procedure is not difficult to complete. As a bonus (as shown in the photo below), the orange loopstick mounting frame is color-coordinated with the Radiwow logo on the R-108 front panel :-)  

     The AM band performance of the stock model does seem to be competitive with the Tecsun PL-380 model as far as sensitivity, DSP selectivity and digital functions, although the audio amp will max out more quickly on a weak signal. The multiple DSP options are quite good at this price point, especially when combined with the correction of the Tecsun PL-380's internally generated heterodyne and digital whine issues. 

Detailed photos are posted at the following links:  RF Circuit Board  https://dreamcrafts.box.com/s/456oocxphu0uytkz8i9trfdhb06750i3

Cabinet Disassembly (Digital and RF Circuit Boards)  https://dreamcrafts.box.com/s/xxhqja4031uo16j1rma41xk0t84ujm0p

Lithium-ion Rechargeable Battery  https://dreamcrafts.box.com/s/zn97mtiathscw54qn5i8tdfs4jesem8d

CC Skywave SSB and R-108... the identical sized Shenzhen "siblings"  https://dreamcrafts.box.com/s/jvenlc0mg6a8lqktld6ouyna3fjzbhaw

73 and Good DX,

Gary DeBock (in Puyallup, WA, USA)


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