[Elecraft] KX3- laptops for I/Q

[Larry Phipps]

Most laptops don't have a stereo input, only mono mic input, so they are 
worthless for SDR. I haven't tested any pc card type sound cards that 
are really good, but some can be acceptable for limited bandwidth if you 
can accept the center spike in the display. I have had very good results 
with my laptop and E-MU 0204 USB sound card.

The SDR Widget sound card should be good since it uses the AK5394A ADC, 
but I completely disagree with their test results of the E-MU 0202. My 
tests using the same software testing suite were MUCH better. Also, they 
didn't test the E-MU 1212m, which uses the AK5394 and gives spectacular 
results.

Even though a lot of emphasis is put on sound cards, I think most casual 
users of SDRs would be surprised at the results that can be obtained 
with basic sound cards... as long as they have stereo line level inputs.

For basic field use with the KX3, there is an SDR app for iPhone / iPad 
/ iPod Touch called iSDR which might be worth looking at. For stereo mic 
input, additional hardware is required, and of course a SoftRock or 
LP-PAN is still required.

Larry N8LP



On 2/1/2012 11:40 AM, elecraft-request at mailman.qth.net wrote:
> Date: Wed, 1 Feb 2012 00:29:03 +0000
> From: Thomas Horsten<thomas at horsten.com>
> Subject: Re: [Elecraft] KX3- laptops for I/Q
> To: Brian Pepperdine<brianpepperdine at sympatico.ca>
> Cc:elecraft at mailman.qth.net
> Message-ID:
> 	<CAPaRxgR-C=Uege91AkYgi14MH58Z8ebRNNo0ZUWTh+jr+=vVdQ at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Brian,
>
> Some laptops are good, some are bad. This varies even between laptops even
> with the same chipset, because the support chips differ. I've found that of
> all the laptops I've tried, only a HP 8440 had a really good chipset for
> SDR sampling up to 92kHz.
>
> Consider getting an external USB soundcard like the E-MU 0202, which works
> great on any laptop, or even the SDR Widget (still in the process of
> building mine, but the performance data is amazing even at 192kHz, beating
> any built-in or external sound cards on the market for this application!)
>
> You probably won't get any decent 192kHz sampling in any laptop. To get the
> noise level acceptable at this sampling rate, very careful design
> considerations have to go into it, which would conflict with the space
> constraints etc. of a laptop.
>
> So far, I haven't seen a really "bad" HP, nor a really good Dell... But
> those are just my experiences, YMMV.
>
> 73, Thomas M0TRN