[Skimmertalk] KX3 with CW Skimmer ?

Mark n2qt n2qt.va at gmail.com
Tue Dec 15 17:05:38 EST 2015


Actually it's not all that hard.  You do need to create a virtual comport to connect to
Cwskimmer so it knows your frequency without taking away the ability to use n1mm etc.
at the same time.  I use Vspe but there are other choices.  Take a look at the LPpan 
website at 
Telepostinc.com       For ideas and guidance, and also sound card setups.
If you change modes the frequency offset will change and your displayed frequency 
will also therefore be off.  On CW the offset is about 1khz which cwskimmer allows
you to specify. 

Also since the offset is only 1khz there will likely be a spike in the response at that
point caused by any little ground loop or low frequency noise.  You can do an offset
in the kx3 to move this away (I think it's 6khz) but you lose the use of the optional
narrow CW filter and the ability to go split in the kx3.

Also when you transmit the I/q output isn't muted and it's at a high enough level I've
had it disrupt the careful I/q balance done in skimmer.  This allows images to show up.
I normally shut off the automatic balance when I operate, after allowing it to calibrate
itself on real signals.

If you use cwskimmer in IF mode, you only get about 22khz of displayed and decoded
spectrum, however the skimmer can follow the rigs frequency. However If your sound 
card is 192khz capable, and you don't want to tune the kx3, you can cover 192khz by
setting the kx3 on a fixed frequency and telling skimmer what it is. (And don't touch it).
This isn't all that useful if you want to actually use the kx3. However if it's just acting as a 
remote skimmer it'll work just fine.

Be aware 160 can have signals strong enough to create images.  If you are using this
as a standalone skimmer set your center freq. at the bottom band edge so the images
are out of band, and won't bother you with bogus decodes.

Mark. N2QT

> On Dec 15, 2015, at 4:18 PM, Bob Wilson, N6TV <n6tv at arrl.net> wrote:
> 
> Google searches indicate some have this working, but it's very complicated
> to get the frequencies displayed accurately since the center of the IF
> shifts every time you move the KX3 tuning knob?
> 
> See WK1K:
> http://www.eham.net/ehamforum/smf/index.php?ehamsid=megt5e81caq3s8knstt5bj8oa0&topic=85050.msg641365#msg641365
> 
> And N1DX:
> 
> http://elecraft.365791.n2.nabble.com/Re-CW-Skimmer-Setup-with-K3-and-KX3-td7605241.html
> 
> It should be much simpler to connect a direct sampling SDR directly to the
> antennas than to the KX3 I/Q output.
> 
> 73,
> Bob, N6TV
> 
>> On Tue, Dec 15, 2015 at 10:21 AM, Steve London <n2icarrl at gmail.com> wrote:
>> 
>> Before you ask "why ?", let me add some verbiage.
>> 
>> N5FO and I are looking at operating the Stew Perry contest from my QTH,
>> and still satisfy this Stew Perry rule by setting up a skimmer at his QTH:
>> 
>>   If you are multi-op, you can get assistance from other humans in your
>>   shack.  We still do not want to encourage the use of packet during the
>>   contest, so would rather you not do that.  If you have a skimmer - go
>>   ahead and use it.  Remote receiving sites within the 100 kM are okay.
>>   If a networked connected skimmer is within 100 kM of you, go ahead
>>   and use it.
>> 
>> His QTH is about 70 kM from my QTH.
>> 
>> 73,
>> Steve, N2IC
>> 
>> 
>>> On 12/15/2015 11:01 AM, Steve London wrote:
>>> 
>>> I see that the KX3 has I/Q output. Can it be interfaced with a CW Skimmer
>>> ?
>>> 
>>> Thanks,
>>> Steve, N2IC
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