[Elecraft] RX I/Q output planned or thought about for the K3/P3?

[Joe Subich, W4TV]

Geoff,

 > I suppose the thing I'm trying to get at is a direct I/Q line from the
 > K3... Whether a software update is possible to add this to the current
 > Stereo Line-Out jack (on the back of the K3) or not.

At present, there simply *is no hardware* capable of providing a direct
I/Q output to the stereo line out jack.  Line Out audio is "0 Hz based"
following the main/sub RX.  I doubt the K3 has enough processing power
to do a separate 15 KHz to 6 KHz I/Q conversion and even if it did the
output bandwidth would be severely limited by the 1st IF ("roofing")
filters.

The P3 certainly has no provision for separate I/Q audio output.  Other
than the display. the entire P3 electronics would need to be duplicated
to generate an I/Q output otherwise the audio (if it could be extracted
from the P3 and there is no DAC to do so)would be limited to the span
and resolution of the P3 display.

As Tony has suggested, the proper way to get wideband I/Q audio from
the K3 is by use of a SoftRock with Clifton Labs isolation amplifier
or an LP-Pan connected to the K3's wideband IF output. Other solutions
would essentially be reinventing the Softrock or LP-Pan and any USB
based solution would likely be limited to a 48 KHz sample rate if it
used one of the commercial USB sound chips.

73,

    ... Joe, W4TV


On 5/9/2012 12:03 AM, Geoff Wolf AB3LS wrote:
> Tony,
>
> Yes I am aware of Softrock and LP-Pan, as well as a whole slew of other
> SDRs you could use with the K3's Buffered IF Output.
>
> I suppose the thing I'm trying to get at is a direct I/Q line from the
> K3... Whether a software update is possible to add this to the current
> Stereo Line-Out jack (on the back of the K3) or not.
>
> 73
> DE AB3LS
>
> On Tue, May 8, 2012 at 11:31 PM, Tony Estep<esteptony at gmail.com>  wrote:
>
>> On Tue, May 8, 2012 at 10:14 PM, Geoff Wolf AB3LS
>> <liltechdude13 at gmail.com>wrote:
>>
>>> ....way to get I/Q data to a computer from ...an extra module....?
>>> =============
>>
>> Well Geoff, one way is to use a Softrock-IF (a kit, available from KB9YIG
>> for less than 30 bucks); another way is to use an LP-Pan (available from
>> http://www.telepostinc.com/LP-PAN.html).  The LP-Pan costs way more but
>> has
>> better dynamic range and other fancy features; nonetheless the little
>> Softrock is a dynamite piece of engineering and does a great job.
>>
>> In either case you will get much better results by adding an outboard sound
>> card instead of your computer's on-board card. I use an EMU0202, no longer
>> made, but others are good too. You take IF out of the back of the K3 and
>> feed the Softrock or LP-Pan, and get I-Q out.
>>
>> Tony KT0NY
>>
>>
>>
>>
>> --
>> http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352
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