[IRCA] 7.5" Longwave Loopstick XHDATA D-808

[Gary DeBock <d1028gary@xxxxxxxxxxx>]

For the admittedly small segment of the DXing community that still has interest in experimentation, an XHDATA D-808 model was successfully enhanced by the transplantation of a 7.5" Longwave loopstick (as part of a project to thoroughly test out the new model's DXing capability on all bands).

The Longwave loopstick was originally developed for the Tecsun PL-380 model, with full construction details posted in the PL-380 "supercharging" article posted at http://www.mediafire.com/file/du3sr5cd9thqvau/7.5inch-LS-PL380.doc/file

It has 122 turns of 100/44 Litz wire on a Type 33 ferrite rod for a target inductance of about 1700 uH. The loopstick was developed as part of an interesting project to make the first Longwave-optimized loopsticks for portables, since stock portables always have MW-optimized loopsticks.


As a result of the Longwave loopstick transplant, the LW sensitivity of the D-808 was greatly enhanced, of course. But in comparison with the 7.5" Longwave loopstick Tecsun PL-380 model, the modified D-808 had a shade less sensitivity in digging out the weaker NDB's. I suspect that the Si4735 DSP chip in the new D-808 has some minor differences in comparison to the Longwave performance of the Si4734 DSP chip in the Pl-380. Despite this, the modified D-808 does have a few advantages over the modified PL-380. When its SSB capability is used by a skilled operator, it can compensate for the minor sensitivity difference. In addition, the Tecsun company removed a lot of the DSP chip shielding in the PL-380 model as a cost-cutting measure around 2012, resulting in an unpleasant digital whine when new PL-380's receive this Longwave modification. As a result, unless you can track down an "old-model" (pre-2012) PL-380, your options at this point are pretty much limited to the D-808 if you want to have a digital-whine-free Longwave-optimized portable.


Currently the XHDATA D-808 has a somewhat murky supply network, with all the Chinese-manufactured models being shipped from China. There are a couple of eBay sellers shipping the D-808 to North America at a price of $112 plus $10 shipping at the current time, but there are no North American suppliers. As such, the future availability and price of the model are somewhat uncertain at this point. I've managed to track down three models (two from eBay, and one from Hiroyuki Okamura in Japan), and all three have been of good quality so far.


Gary DeBock (in Puyallup, WA, USA)


  
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