[Elecraft] SDR-IF and I/Q questions

[Edward R. Cole]

Responding the message repeated, below.

Planning on a KX3 and user of SDR sw I am interested in this topic, 
though I have no experience with SDR-IF, PSDR-IF, or HDSDR.  I have a 
SDR-IQ which interfaces using USB-2.0 and mainly run Spectravue with 
it (though I have run Linrad).  Also the K3+LPPan+emu0202 which uses 
USB-2.0, also.  These can also utilize software that support 
soundcard input (with proper drivers).

My impression was that the KX3 IQ output was analog baseband and not 
converted to USB. (?).

73, Ed - KL7UW

Message: 16
Date: Tue, 8 Nov 2011 14:36:53 -0600
From: "Richard Fjeld" <rpfjeld at embarqmail.com>
Subject: [Elecraft] SDR-IF and I/Q questions
To: "elecraft posting" <elecraft at mailman.qth.net>
Message-ID: <A1A1511B47FF46F7A35DA9C84AFA1D5E at BIOSTAR>
Content-Type: text/plain;       charset="Windows-1252"

This is the new subject title, and needs some background, so it will 
be lengthy this time.

Some of us use SDR-IF, and the new KX3 will use SDR-I/Q methods for 
connecting to a computer  running SDR software and seeing the results 
on a monitor. (The SDR-IF users must provide a SDR-IF receiver to 
bring out the I/Q leads. It is to be assumed that the SDR-IF receiver 
is functioning correctly.)  With both types,  I/Q leads are brought 
to a computer. (If you are wondering, I am on the list for a KX3)

So the computer AND THE SOFTWARE are the center of attraction here. 
This is where great things may happen. (Emphasis on 'may')

Some of us are at different experience levels, but I think we all 
would have, and still would, appreciate help to reach 
satisfaction.  The reflector is the place for this. The real question 
is; Should this be on a dedicated thread?  When I read the KX3 was 
going to be SDR capable, I wondered if Elecraft realized what it was 
getting into for the reflector?

IMHO, The weak link in this SDR thing is the computer and software. 
PSDR-IF has great control features, but when I compare it to HDSDR, 
the latter does a great job of displaying the signals and is very 
sensitive. PSDR-IF looks at both directions in spectrum, so far, I 
can only get HDSDR to look upward in spectrum.

We can't get rid of the mirrored images in PSDR-IF.  ('WE' includes a 
friend who still owns 3 of 6 Flex radios he has owned, and 2 of 4 
SDR-IF receivers. He is no beginner to SDR.)

My thanks to all who responded. Can't take the space to recap 
everything, but Sebastian suggested mirrored images are due to ground 
loops. It has been long enough that I can't remember if I checked 
that, and I will.  However, why just PSDR-IF and not HDSDR that is 
affected?  A ground loop should affect both. Still, it is worth checking out.

Basically, I'm disappointed with the software. I don't mind 
installing and setting some options for my type of equipment, but 
from there-on I expect it to function conveniently and nearly as well as a P3.

The question for today is; have any Elecraft users achieved that goal 
with a computerized pan-adapter? And if so, with what software?  And 
if so, do you use a USB to Serial, or straight Serial?


Thanks, from now on it will be shorter.

Richard Fjeld, n0ce
rpfjeld at embarqmail.com
I'd rather be learning.







73, Ed - KL7UW, WD2XSH/45
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