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Re: [IRCA] New C.Crane "Skywave" Vs. Tecsun PL-380-- Daytime DX Shootout
Gary -
Intelligibility is almost completely determined by frequencies below 3000 Hertz, hence the 3400 Hertz upper limit in the phone system. The amplitude responses of the two receivers is pretty identical below 3000 Hertz. The noise at 3000 Hertz and above is just a bad distraction in the Skywave.
Chuck
> Date: Mon, 29 Dec 2014 23:26:22 +0000
> From: d1028gary@xxxxxxxxxxx
> To: irca@xxxxxxxxxxxxxxxx
> Subject: Re: [IRCA] New C.Crane "Skywave" Vs. Tecsun PL-380-- Daytime DX Shootout
>
> <<< I don't think so. The audio response for the two is very similar (identical?) from 100 - 2500 Hertz. It's just below 3000 that a big difference can begin to be noted. There's about a 15 dB difference from that point upward, and it'd sue to "wideband" white noise.
> Take a look at a frequency plot and you'll easily see what I mean. >>>
> Chuck
>
> Chuck, I have no doubt that you are correct that the barefoot "Skywave's" audio response has a huge dose of white noise starting just below 3000 hertz, and going upward from there.
>
> My point is that for transoceanic DXing, almost nobody is going to spend the $$ to go to the ocean coast and then try chasing DX with a barefoot Skywave (or any other barefoot pocket radio, for that matter). When an FSL antenna inductively couples to one of these pocket radios and provides a huge gain boost, it typically chops off the higher audio frequencies in the DX station's audio-- which should make the Skywave's high frequency audio bias pretty much irrelevant in DX audio MP3's. As for how this presumption will play out in actual DXing on the ocean side cliffs, only time will tell. But I do know that the combination of the PL-380's 1 kHz DSP filtering and the FSL's inductive coupling boost has usually resulted in a serious loss of high frequency audio in DX station MP3's, making it seem desirable to try correcting the issue.
>
> Gary
>
>
> ----- Original Message -----
>
> From: "Chuck Hutton" <charlesh3@xxxxxxx>
> To: irca@xxxxxxxxxxxxxxxx
> Sent: Monday, December 29, 2014 11:02:55 AM
> Subject: Re: [IRCA] New C.Crane "Skywave" Vs. Tecsun PL-380-- Daytime DX Shootout
>
> Gary -
> I don't think so. The audio response for the two is very similar (identical?) from 100 - 2500 Hertz. It's just below 3000 that a big difference can begin to be noted. There's about a 15 dB difference from that point upward, and it'd sue to "wideband" white noise.
> Take a look at a frequency plot and you'll easily see what I mean.
> Chuck
>
> > Date: Mon, 29 Dec 2014 08:54:12 +0000
> > From: d1028gary@xxxxxxxxxxx
> > To: irca@xxxxxxxxxxxxxxxx
> > Subject: Re: [IRCA] New C.Crane "Skywave" Vs. Tecsun PL-380-- Daytime DX Shootout
> >
> > Chuck,
> >
> > Given the likelihood that these new "Skywave" portables will be used with extremely high-Q FSL antennas during actual transoceanic DXing, the high-treble audio of the "Skywave" may help to compensate a little for the tendency of the FSL's to chop off the higher audio frequencies when they zero in on DX with their razor-sharp tuning system. Up until now the PL-380's 1 kHz DSP filtering and the FSL's razor sharp tuning system have been kind of a double whammy on DX stations' higher audio frequencies, resulting in somewhat "muddy" sounding audio during typical MP3's. Previously, the only way to correct this issue was to switch to 2 kHz DSP filtering on the PL-380, but that usually results in unacceptable splatter from domestic stations. Time will tell if the "Skywave's" high-treble audio provides a little more balance in MP3's of DX stations.
> >
> > Gary
> >
> >
> > ----- Original Message -----
> >
> > From: "Chuck Hutton" <charlesh3@xxxxxxx>
> > To: irca@xxxxxxxxxxxxxxxx
> > Sent: Sunday, December 28, 2014 10:42:15 PM
> > Subject: Re: [IRCA] New C.Crane "Skywave" Vs. Tecsun PL-380-- Daytime DX Shootout
> >
> > I was somewhat bothered by a lot of hiss in the Skywave audio. It's easily visible in a spectrum plot.
> > To a lesser degree, the 380 audio had too much low frequency rumble.
> > Doing a good lowpass and highpass filtering on both, I was left with audios that sounded identical from the two receivers.
> > Chuck
> >
> > > From: canswl@xxxxxxxxx
> > > Date: Mon, 29 Dec 2014 06:04:16 +0000
> > > To: irca@xxxxxxxxxxxxxxxx
> > > Subject: Re: [IRCA] New C.Crane "Skywave" Vs. Tecsun PL-380-- Daytime DX Shootout
> > >
> > > Impressive results, Gary. I was very impressed with the 550 clip. Wow!
> > > As for the others, the C Crane receiver was so much less fatiguing to
> > > listen to. Great audio, for sure! Thanks for doing the side by side
> > > comparisons! 73,...Walt Salmaniw, Victoria, BC
> > >
> > > On Mon, Dec 29, 2014 at 5:40 AM, <d1028gary@xxxxxxxxxxx> wrote:
> > >
> > > > Hello All,
> > > >
> > > > With clear weather and lots of open space in our back yard, it was time
> > > > for a full Shootout between the Si4734-chip-powered Tecsun PL-380 and the
> > > > new Si4736-chip-powered C.Crane Skywave portable. Both stock models were
> > > > checked out for normal operation before the contest, with new batteries and
> > > > an equal chance to receive six fringe MW stations just after local noon..
> > > >
> > > > The new Skywave is significantly smaller than the Tecsun PL-380 (see photo
> > > > at
> > > > http://www.mediafire.com/view/8o5mdtt1bc1rfik/CCraneSkywaveDisassembly-04_(Large).jpg
> > > > ), and at $89.95 (before shipping) costs about twice as much. The Tecsun
> > > > PL-380 stock model was chosen for this Shootout because it has become the
> > > > favorite of Ultralight radio Transoceanic DXers, with a generous range of
> > > > functions combined with "toned down" soft mute. Its stock loopstick places
> > > > it near the top of the ULR class in sensitivity, and with DSP filtering
> > > > down to the 1 kHz level it provides fairly representative performance of
> > > > all the Tecsun Si4734 DSP chip Ultralights.
> > > >
> > > > Rather than tell you immediately how the Shootout went, I will let you
> > > > form your own opinion by posting six MP3's of the relative reception by the
> > > > PL-380 Vs. the Skywave in receiving the daytime DX fringe stations. In each
> > > > MP3 both the PL-380 and the Skywave were set on the 1 KHz DSP setting, and
> > > > both were pointed in the same direction. In each MP3 the PL-380 receives
> > > > the fringe station for the first 20 seconds, and the Skywave receives the
> > > > same fringe station for the final 20 seconds.
> > > >
> > > > 550 KARI Blaine, WA (5 kW at 127 miles)
> > > > http://www.mediafire.com/listen/dd8dok6ujeh50cz/550-KARI-PL380vsSkywave.MP3
> > > >
> > > > 690 CBU Vancouver, BC (50 kW at 148 miles)
> > > > http://www.mediafire.com/listen/hj3khn0zjep3pxc/690-CBU-PL380vsSkywave.MP3
> > > >
> > > > 750 KXTG Portland, OR (50 kW at 117 miles)
> > > > http://www.mediafire.com/listen/06uc2a15yas4y57/750-KXTG-PL380vsSkywave.MP3
> > > >
> > > > 1070 CFAX Victoria, BC (10 kW at 100 miles)
> > > >
> > > > http://www.mediafire.com/listen/44vpx852aa7pwn4/1070-CFAX-PL380vsSkywave.MP3
> > > >
> > > >
> > > > 1420 KITI/ KUJ Centralia and Walla Walla, WA (5 kW at 46 miles and 202
> > > > miles)
> > > >
> > > > http://www.mediafire.com/listen/b2apvjdi5uwhksw/1420-KITI-KUJ-PL380vsSkywave.MP3
> > > >
> > > > 1470 KELA Centralia, WA (5 kW at 46 miles)
> > > >
> > > > http://www.mediafire.com/listen/glppgdt26jzcnlc/1470-KELA-PL380vsSkywave.MP3
> > > >
> > > > Comments: The Si4734 DSP chip in all of the Tecsun Ultralights tends to
> > > > clip off the higher audio frequencies in the 1 kHz DSP setting, leaving the
> > > > audio with somewhat of a "muddy" sound. Obviously, the Si4736 chip in the
> > > > Skywave not only solves this issue, but solves the heterodyne issue
> > > > (audible in the 1420 kHz MP3) as well. As for why the Skywave seems to have
> > > > a slight sensitivity edge over the PL-380 (except on 550, where it smokes
> > > > the PL-380), it could either be the result of a superior loopstick, or
> > > > superior sensitivity of the Si4736 chip. Further testing should reveal the
> > > > cause.
> > > >
> > > > Verdict: The Si4736 DSP chip in the Skywave is a major improvement over
> > > > the Si4734 chip in the Tecsun DSP Ultralights. Although there may be some
> > > > jokes about the Skywave's cost being "sky high," the radio seems to be
> > > > everything claimed by C.Crane, at least in its MW performance. This model
> > > > should see a lot of action among Transoceanic MW DXers, where its superior
> > > > audio and heterodyne-free reception should make a significant difference in
> > > > split-frequency results.
> > > >
> > > > 73 and Good DX,
> > > > Gary DeBock (in Puyallup, WA, USA
> > > >
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