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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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