Softrock vs. LP-PAN

[Bob-19]

I've been using a K2 IF version of V6.2 Softrock Lite as a pandapter
interface with my K2, and the results are OK but not great - among other
things, the K2 IF is very prominent on the screen. How much improvement
could I expect if I replace the Softrock with an LP-PAN? (I have a Z10000
buffer amp in my K2, I'm using an E-MU 0202 sound card and I'm using
PowerSDR-IF software in my computer).
 
Thanks,
 
Bob W1SRB
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[Jack Smith-6]

  Bob:

There are two possible 'spike' concerns here.

One is the so-called 'zero' point spike in the software defined
receivers. This is mostly a function of ground loops between the sound
card and the Softrock. It can be removed by transformers or some careful
work with the audio cables and connections. This spike will be located
at the Softrock center frequency and will be present whether or not the
Softrock is connected to the K2. The LP-PAN has transformers but similar
transformers can be externally added to a Softrock.

The second spike is BFO leakage from the K2 back into the panadapter.
This spike will shift slightly in frequency as USB or LSB or CW CW-R is
selected.  This spike is radiated from the K2 for reasons that are
discussed at my web page
http://www.cliftonlaboratories.com/k2_interface.htm and in the Z10000B
buffer amplifier K2 installation instructions.
http://www.cliftonlaboratories.com/Documents/Installing%20the%20Z10000B-K2%20In%20an%20Elecraft%20K2%20Transceiver.pdf 
It will be present at the same level in any panadapter connected to the
K2, whether it is the LP-PAN or Softrock, one of my HP spectrum
analyzers or, for that matter, a P3.

However, the strength of the leakage signal depends upon where the
Z10000B buffer amplifier obtains its IF sample. The Z10000B K2
installation instructions suggest two possible sample points, one at the
output from the post mixer amplifier and the second at the input to the
post mixer amplifier. There are plus and minus points with respect to
each possible connection point, but the BFO leakage will be much reduced
if the connection is made at the input to the post mixer amplifier, as
the post mixer amplifier provides additional BFO leakage isolation. The
Z10000B K2 installation instructions show examples of leakage with both
connection points.

Additionally, I suspect some variation in BFO leakage level is possible
depending on cable routing and the like.

Jack K8ZOA
www.cliftonlaboratories.com



As the
On 10/5/2010 2:19 PM, Bob wrote:

> I've been using a K2 IF version of V6.2 Softrock Lite as a pandapter
> interface with my K2, and the results are OK but not great - among other
> things, the K2 IF is very prominent on the screen. How much improvement
> could I expect if I replace the Softrock with an LP-PAN? (I have a Z10000
> buffer amp in my K2, I'm using an E-MU 0202 sound card and I'm using
> PowerSDR-IF software in my computer).
>
> Thanks,
>
> Bob W1SRB
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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