Re: [IRCA] Tecsun PL-300WT-- A Sizzler on AM & FM, A Fizzler on LW and SW
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Re: [IRCA] Tecsun PL-300WT-- A Sizzler on AM & FM, A Fizzler on LW and SW



Hi Paul,
 
Thanks for the information on the PL-300WT's AM-FM DSP chip, and of course  
the radio's uneven performance on LW and SW certainly makes me agree  with 
your statements.
 
It's obvious now that Tecsun designed the breakthrough DSP performance  to 
apply only on AM and FM, and the LW and SW bands are mediocre additions 
which  border on the defective. I myself have been puzzling why Tecsun would 
even wish  to include them in this innovative receiver, but I suppose that if 
they were  lacking, purchasers might think that this was only another typical 
 AM-FM portable receiver for local reception (which of course would be a  
great mistake), and pass over this receiver in favor of its 4-band  
competitors.
 
73, Gary    
 
 
In a message dated 6/1/2009 10:16:22 P.M. Pacific Daylight Time,  
texnote@xxxxxxxxx writes:


Gary,

According to the ebay description of the Tecsun  PL-300WT (by the seller 
"liypn"), this radio uses the Silicon Labs Si4737 DSP  chip which can only 
demodulate MW, FM, and the Weather Band. See slide 12 of  
https://www.silabs.com/Marcom%20Documents/Resources/Si473x_Presentation.pdf
and
https://www.silabs.com/products/audiovideo/amfmreceivers/Pages/Si473637.aspx

If  liypn's information is correct (verified by opening the radio up and 
locating  the Silicon Labs chip), Tecsun must use this chip for MW/FM, and a 
separate  non-DSP single or dual conversion demodulator/tuner with much 
poorer  selectivity and sensitivity for shortwave.

For shortwave enthusiasts,  it will be interesting to see which one of the 
forthcoming DSP radios from  Tecsun use the Si4734 or Si4735 chips, which 
demodulate MW, FM, and  SW.

In terms of price, the Si4737 chip starts at $3.06 in quantities of  10K; 
the Si4734/35 starts at $3.27 in quantities of  10K.

Paul

--- On Mon, 6/1/09, D1028Gary@xxxxxxx  <D1028Gary@xxxxxxx> wrote:

> From: D1028Gary@xxxxxxx  <D1028Gary@xxxxxxx>
> Subject: [IRCA] Tecsun PL-300WT-- A Sizzler  on AM & FM, A Fizzler on LW 
and SW
> To: irca@xxxxxxxxxxxxxxxx,  am@xxxxxxxxxxx, ultralightdx@xxxxxxxxxxxxxxx, 
odxa@xxxxxxxxxxxxxxx
>  Date: Monday, June 1, 2009, 9:45 PM
> Hello All,
>  
>  Although evidence indicates that a huge ordering boom has
> started for  the  
> DSP-enhanced Tecsun PL-300WT Ultralight radio, for those  of
> you still on the 
>  fence about this innovative pocket  radio, some further
> information may be 
> of   interest.
>  
> Tecsun's primary focus in developing this  breakthrough
> model appears to  
> have been in transforming  the AM and FM circuitry to set
> new standards of  
>  weak-signal performance, and with superlative sensitivity
> and  selectivity  in 
> both bands, they appear to have accomplished  their purpose.
> However, the  
> model does have other bands  included in the package, which
> frankly appear to  
> have  been neglected, and border on the substandard.
>  
> The  Longwave band (153-513 kHz) of the PL-300WT  was
> thoroughly  searched 
> for any possible signals at local sunset, without   any
> results. This is not 
> unusual for small portables with LW  capability, but
> in  most cases, one or two 
> of the  strongest beacons will at least make an
> appearance  at sunset.  
>  
> The Shortwave bands of the PL-300WT are filled with  local
> MW station spurs, 
>  and mixing products. The signal  of local KSUH-1450 has a
> "coverage" of 
> about 6  Mhz on  the Tecsun's shortwave bands, from 9.5
> Mhz to 15.5 Mhz. WWV on  
> 10 Mhz is  really just a mixing product with KSUH.
>  Legitimate SW stations 
> have anemic  signal levels, to the point  of being
> crowded out by the MW spurs. 
>  The Tropical Band  is especially bad, with a sorry
> collection of MW  
>  station spurs and mixing products overpowering any
> legitimate   stations.
>  
> Of course the argument could be made that for  a $50
> receiver, Tecsun has  
> already provided an  outstanding value with the superlative,
> DSP-enhanced  
>  reception on the AM and FM bands. The puzzling aspect is
> why Tecsun  would  
> include such dreadful LW and SW sections in a model  which
> is otherwise so  
> superb. In summary, if LW or SW  reception is your top
> priority in a  portable, my 
> strong  recommendation would be to avoid the PL-300WT,
> despite its   
> breakthrough DSP capabilities.
>  
> 73, Gary  DeBock
>  
>  
>      
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