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

[Edward R. Cole]

Mike,

Use of other SDR sw with the K3 can only be implemented via using the 
1st IF output to "secondary SDR hardware" such as SoftRock or LP-Pan 
that do provide interface to a computer where SDR programs like 
PowerSDR can be loaded.  At this point it appears to me the only  SDR 
sw that can be uploaded directly into the K3 is Elecraft's firmware.

I think at the time the K3 was designed, SDR's were very new on the 
landscape and all of them had one large problem of lack of 
availalble, viable sw to run them.  Elecraft wisely decided to 
develop the SDR sw for the K3, but failed to realize the interest 
there would be for running the K3 on alternative SDR programs, thus 
there was no external I/F provided to the IQ data stream.  Apparently 
"after the fact" is hard to provide.

In designing the KX3 (much later in time) Elecraft responded to the 
wishes of many for access to the IQ data by providing output of the 
baseband audio stream. Still not quite what was asked for, but very 
usable with several after-market SDR programs.

The promise of the SDR radio is non-obsolescence thru continual 
ability to write updates or even new software to run the radio.  The 
second aspect of that is the desired to run alternative SDR applications.

In the competitive radio market we will see more and more SDR 
technology used to offer the best (and latest) features and versatility.

In most SDR one sees conversion of RF to data by A/D conversion and 
signal processing and demod done in sw.  Since the radio is 
essentially defined by the sw program it can be re-designed 
forever.  Some designs use a quadrature mixer at RF before conversion 
to digital; some just go directly to digital and do it all under 
sw.  To produce audio for listening to the radio a D/A conversion is 
performed.  Soundcards provide both A/D and D/A hardware so were 
naturally included in early SDR design to keep costs in line.  But 
A/D and D/A technology is progressing rapidly beyond so I would 
expect to see more SDR radio's that directly connect on a digital 
level with the computer (or have an embedded processor like the K3).

73, Ed - KL7UW

---------------------
Date: Wed, 09 May 2012 08:01:05 -0500
From: Mike Schwendeman <mike at s3com.net>
Subject: Re: [Elecraft] RX I/Q output planned or thought about for the
         K3/P3?
To: elecraft posting <elecraft at mailman.qth.net>
Message-ID: <4FAA6A91.5000807 at s3com.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Geoff;

As far as I know, the K3 is NOT an SDR.  (Search the Elecraft web site
for better information; If it were an SDR, I am very sure that the folks
at Elecraft would be very sure to mention this.)  The KX3 is reported to
be an SDR, and is, per the block diagram.

I am also very interested in an "easy way" to get a version of PowerSDR
to operate with the KX3's I/Q outputs.  This is a very new field for a
lot of folks, and so there will be a learning curve.  But the results
are well worth the effort.  (Me, I'm fighting mirror images on some
apps, using a low-cost SDR RX..!)

73;    -Mike-    K?JTA


73, Ed - KL7UW, WD2XSH/45
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