[Elecraft] What's best Soundcard Interface for KX3

[Don Wilhelm]

John,

That is mixing apples and oranges.
The RX I/Q is a quadrature output that can be used as input to a 
panadapter software application or to the PX3.  Yes, it requires stereo 
for those applications.
They can display up to a 200 kHz slice of the band (if the bandwidth of 
the soundcard is great enough) and can produce either a real time 
spectrum display or a waterfall (signals over time) or both.
That is *only* display - there is no decoding of signals.

Decoding of digital mode signals requires only one channel to an 
application for decoding (and transmitting) the audio tones of the 
transceiver output when that transceiver is tuned to one or more digital 
stations.  The main purpose of that software application is to decode 
digital signals.
Yes, those applications contain a waterfall display so you can identify 
a particular station and click on it to tune to it (and decode it).

Theoretically, one channel of the RX I/Q could be routed to the digital 
software application running on the computer, but the bandwidth would be 
restricted to whatever width that application is designed to handle 
(4kHz or less).
But, the problem is the level available from the RX I/Q is too low to 
adequately drive those software applications.

So bottom line -- if you are using a digital mode software application, 
use the headphone output to drive one channel of the soundcard 
(typically the left channel).  If you are driving a soundcard for a 
panadapter display, use the RX I/Q output.

73,
Don W3FPR



On 4/10/2016 4:12 PM, John Pitz wrote:
> On the topic of sound cards, I was wondering what the advantages are to
> using the IQ output of the KX3 as opposed to feeding the headphone jack
> into the input of the soundcard?  I believe the IQ output requires
> stereo input to work, but what are the advantages?  I have seen on this
> list quite a few people with radios that have an IQ output still use the
> headphone output to decode the digital modes.  I am under the impression
> that the PX3 can display a 200KHz slice of the RF spectrum using the IQ
> outputs whereas the best I can get out of fldigi is about 4KHz.  Is
> there any way to coerce fldigi to display a wider chunk of the band?  I
> am running fldigi on Linux.
>
>