[IRCA] Tecsun PL-300WT DSP-enhanced Ultralight Radio-- Further Details

[D1028Gary@xxxxxxx]

Hello All,
 
With a large number of medium-wave DXers apparently waiting to receive  
their new PL-300WT's from the Chinese eBay sellers "Liypyn" and "Anon-co," more 
 information regarding this innovative pocket radio may be of interest.
 
The PL-300WT was thoroughly disassembled here to gain various technical  
information, and the radio does indeed have some very unusual characteristics. 
 There is no alignment system designed for either the AM or FM bands, and 
no  frequency limit adjustments or upper-band trimming capacitors were found. 
The  new DSP chip was designed to provide optimum performance on both 
bands, without  alignment. Does it accomplish this purpose? Basically, yes-- the 
out-of-the  box performance was very good on my PL-300WT model, as reported 
previously.  However, despite the manufacturer claims, the loopstick can 
indeed be aligned.  Although its construction certainly doesn't make this job 
easy, a hobbyist can  peak the coil on a 600 kHz signal, and gain some 
additional low-band AM  sensitivity by doing so. The final aligned inductance of 
the single coil is  about 282 microhenries.
 
For the typical DXer who does not enjoy taking radios apart, the new  
PL-300WT should be an ideal model, assuming that the same very good  
out-of-the-box performance applies to other such radios. Tecsun's  no-alignment design 
is quite an innovation. 
 
The PL-300WT's DSP chip apparently is designed to provide maximum  
sensitivity on all AM frequencies when the loopstick inductance is fixed around  the 
282 microhenry value. This makes the PL-300WT's AM RF design significantly  
different than that of the Eton E100 and other radios with single-coil  
loopsticks, which benefit greatly from a Slider loopstick which can  adjust 
coil inductances along with the changing frequencies. In the PL-300WT, so  such 
adjustment is needed, and as long as the loopstick shows an inductance of  
around 282 microhenries from the single coil, maximum sensitivity should be  
possible. This means that although a Slider loopstick transplant will not  
benefit the PL-300WT, a larger fixed-coil loopstick providing the 282 
microhenry  inductance will boost the sensitivity greatly (this has already been 
done on the  PL-300WT here, using a 7.5" Amidon ferrite bar wound with a 
40/44  Litz wire coil). Photos of the disassembled PL-300WT have been uploaded 
to the  Ultralightdx Yahoo group site, for those interested. 
 
The PL-300WT's front-panel access door to the world time selector  switch 
was stuck on my review model, and stubbornly refused to open.  After 
completely disassembling the radio, I gently attempted to open the  access door from 
the back side-- which made the door completely fall out.  All attempts to 
make it work have failed-- the time switch door has apparently  decided it 
was "time" to teach me a lesson. Beware of its flimsy  construction.
 
As reported previously, the LW and SW bands on the PL-300WT are mediocre at 
 best, and my investigation confirmed that the LW band does not receive  
signals from the loopstick. Since I've yet to receive any LW signals on my  
review model, I'm still wondering how or if Tecsun really intended  this band 
to receive any signals.
 
In summary, the PL-300WT's out-of-the-box AM and FM performance is truly  
remarkable, and more than justifies the modest $50 price, in my opinion. I  
hope that the legion of DXers who have purchased this breakthrough DSP model  
will be equally satisfied in the exciting medium-wave DX capability.
 
73, Gary DeBock
 
 
        
**************Mortgage rates dropped. Record lows. $200,000 for $1,029/mo 
Fixed. LendingTree® 
(http://pr.atwola.com/promoclk/100126575x1222627882x1201465404/aol?redir=http:%2F%2Fwww.lendingtree.com%2Fborrower%2Falliance%2Ffrom.a
sp%3Fwhereto%3Dpr
omopagev3%26promo%3D00279%26loan%5Ftype%3D2%26source%3D2889570%26esourceid%3D2889570%26800num%3D1%2D800%2D289%2D3915%26AdType%3D2)
_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://montreal.kotalampi.com/mailman/listinfo/irca

Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers

For more information: http://www.ircaonline.org

To Post a message: irca@xxxxxxxxxxxxxxxx