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using P3 and Skimmer

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DOUGLAS ZWIEBEL

using P3 and Skimmer

I have noted on the P3 panadapter page from Elecraft, that one of the
"features" or uses is cited as

http://www.elecraft.com/P3/p3.htm (bullet #11)
Buffered IF output to drive other equipment (CW Skimmer etc.)

Can anyone describe for me just how this is specifically accomplished for
use with Skimmer? I don't see any references to "how to hook it up with
Skimmer" anywhere in the P3 user's manual, while I see a lot of
documentation for "how to" with LP-Pan.

Thanks,
de Doug KR2Q

K3 SN: 295, 822
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Don Wilhelm-4

Re: using P3 and Skimmer

Doug,

The setup with CW Skimmer is about the same as for LP-Pan. CW Skimmer
is only the software, and it needs a baseband signal having I/Q outputs
to operate. Such a signal can be obtained from LP-Pan, or a Softrock
receiver, or a variety of other SDR devices that provide I/Q signals to
the soundcard inputs.

I also note that there is a slight inconsistency between those "bulleted
features" and the P3 manual.
The manual states that its INPUT should come from a buffered IF output
on the transceiver, however the P3 OUT signal comes from a 3 dB splitter
- it apparently is not separately buffered in the P3.

73,
Don W3FPR

On 8/28/2011 5:51 PM, DOUGLAS ZWIEBEL wrote:
> Buffered IF output to drive other equipment (CW Skimmer etc.)
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David Gilbert

Re: using P3 and Skimmer

In reply to this post by DOUGLAS ZWIEBEL

Hi, Doug.

It cannot be done without the addition of some other SDR hardware, such
as an LP-Pan or SDR-IQ or Softrock.

I publicly, privately, and unsuccessfully lobbied for well over six
months prior to the introduction of the P3 for Elecraft to include
buffered I/Q outputs in it so that it could be used with third party SDR
software like CW Skimmer. The fact that it doesn't is why I don't own
one and instead bought an LP-Pan. There are so many interesting things
that can be accomplished with SDR applications that I don't want to be
without that capability, and in my opinion buying two sets of hardware
to do essentially the same thing is an unnecessary redundancy.

The upcoming KX3 will have buffered I/Q outputs, though, so clearly it
could have been accomplished without undue cost adders. In my opinion,
it would have made far more sense to include it in the P3.

73,
Dave AB7E

On 8/28/2011 2:51 PM, DOUGLAS ZWIEBEL wrote:

> I have noted on the P3 panadapter page from Elecraft, that one of the
> "features" or uses is cited as
>
> http://www.elecraft.com/P3/p3.htm (bullet #11)
> Buffered IF output to drive other equipment (CW Skimmer etc.)
>
> Can anyone describe for me just how this is specifically accomplished for
> use with Skimmer? I don't see any references to "how to hook it up with
> Skimmer" anywhere in the P3 user's manual, while I see a lot of
> documentation for "how to" with LP-Pan.
>
> Thanks,
> de Doug KR2Q
>
> K3 SN: 295, 822

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Jack Smith-6

Re: using P3 and Skimmer

In reply to this post by Don Wilhelm-4

Don:

I recently had a question from a prospective customer for a Z10000B
buffer amplifier about the need for additional isolation if a Softrock
is used with the P3's splitter IF output.

I can't find a spec for the P3's isolation between the IF output port
and the IF Input, but 30 dB isn't a bad estimate for a 3 dB hybrid
splitter.

Typical local oscillator leakage out of a Softrock is -40 dBm, so a -70
dBm signal (approximately) will be injected into the P3's input if a
Softrock is connected to the P3's IF out port. This will appear as a
spurious pip on the P3's display at around -70 dBm.

The LPPan has isolation and it's leakage is not a problem when used in
this fashion. But, I believe a Softrock will require additional
isolation, on the order of 60 dB or so, in order to be useful without
injecting a spurious pip into the P3.

Jack K8ZOA

On 8/28/2011 7:41 PM, Don Wilhelm wrote:

> Doug,
>
> The setup with CW Skimmer is about the same as for LP-Pan. CW Skimmer
> is only the software, and it needs a baseband signal having I/Q outputs
> to operate. Such a signal can be obtained from LP-Pan, or a Softrock
> receiver, or a variety of other SDR devices that provide I/Q signals to
> the soundcard inputs.
>
> I also note that there is a slight inconsistency between those "bulleted
> features" and the P3 manual.
> The manual states that its INPUT should come from a buffered IF output
> on the transceiver, however the P3 OUT signal comes from a 3 dB splitter
> - it apparently is not separately buffered in the P3.
>
> 73,
> Don W3FPR
>
> On 8/28/2011 5:51 PM, DOUGLAS ZWIEBEL wrote:
>> Buffered IF output to drive other equipment (CW Skimmer etc.)
> ______________________________________________________________
> Elecraft mailing list
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>
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Don Wilhelm-4

Re: using P3 and Skimmer

Jack,

Thanks for that information.
I was not thinking about the P3 display. Harmful injection into the K3
would be no problem because it has a buffered output IF output, but you
are correct, the Softrock LO will produce a spur on the P3 display even
if it does not get into the K3 IF.

73,
Don W3FPR

On 8/28/2011 8:42 PM, Jack Smith wrote:

> Don:
>
> I recently had a question from a prospective customer for a Z10000B
> buffer amplifier about the need for additional isolation if a Softrock
> is used with the P3's splitter IF output.
>
> I can't find a spec for the P3's isolation between the IF output port
> and the IF Input, but 30 dB isn't a bad estimate for a 3 dB hybrid
> splitter.
>
> Typical local oscillator leakage out of a Softrock is -40 dBm, so a -70
> dBm signal (approximately) will be injected into the P3's input if a
> Softrock is connected to the P3's IF out port. This will appear as a
> spurious pip on the P3's display at around -70 dBm.
>
> The LPPan has isolation and it's leakage is not a problem when used in
> this fashion. But, I believe a Softrock will require additional
> isolation, on the order of 60 dB or so, in order to be useful without
> injecting a spurious pip into the P3.
>
> Jack K8ZOA
>
>
>

Joe Subich, W4TV-4

Re: using P3 and Skimmer

In reply to this post by David Gilbert

> The upcoming KX3 will have buffered I/Q outputs, though, so clearly
> it could have been accomplished without undue cost adders. In my
> opinion, it would have made far more sense to include it in the P3.

The circuit of the P3 and the KX3 are massively different. If you had
bothered to read the P3 manual and study the block diagram/circuit
description you would not have made such a ridiculous statement.

The P3 does not create audio internally *at all* - to generate I/Q
would require essentially duplicating the P3's entire "IF" along
with a separate controller to maintain independent tracking frequency
control, an independent "wideband" I/Q audio output and digital to
analog converters.

73,

... Joe, W4TV

On 8/28/2011 8:08 PM, David Gilbert wrote:

>
> Hi, Doug.
>
> It cannot be done without the addition of some other SDR hardware, such
> as an LP-Pan or SDR-IQ or Softrock.
>
> I publicly, privately, and unsuccessfully lobbied for well over six
> months prior to the introduction of the P3 for Elecraft to include
> buffered I/Q outputs in it so that it could be used with third party SDR
> software like CW Skimmer. The fact that it doesn't is why I don't own
> one and instead bought an LP-Pan. There are so many interesting things
> that can be accomplished with SDR applications that I don't want to be
> without that capability, and in my opinion buying two sets of hardware
> to do essentially the same thing is an unnecessary redundancy.
>
> The upcoming KX3 will have buffered I/Q outputs, though, so clearly it
> could have been accomplished without undue cost adders. In my opinion,
> it would have made far more sense to include it in the P3.
>
> 73,
> Dave AB7E
>
>
>
>
> On 8/28/2011 2:51 PM, DOUGLAS ZWIEBEL wrote:
>> I have noted on the P3 panadapter page from Elecraft, that one of the
>> "features" or uses is cited as
>>
>> http://www.elecraft.com/P3/p3.htm (bullet #11)
>> Buffered IF output to drive other equipment (CW Skimmer etc.)
>>
>> Can anyone describe for me just how this is specifically accomplished for
>> use with Skimmer? I don't see any references to "how to hook it up with
>> Skimmer" anywhere in the P3 user's manual, while I see a lot of
>> documentation for "how to" with LP-Pan.
>>
>> Thanks,
>> de Doug KR2Q
>>
>> K3 SN: 295, 822
> ______________________________________________________________
> Elecraft mailing list
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> Post: mailto:[hidden email]
>
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>

k.igor

Re: using P3 and Skimmer

>> Dave AB7E:
> I publicly, privately, and unsuccessfully lobbied for well over six
> months prior to the introduction of the P3 for Elecraft to include
> buffered I/Q outputs in it so that it could be used with third party SDR
> software like CW Skimmer.
This was brought few times already and pretty much was black holed by
Elecraft. The reason is that too much need to be done in hardware and
software for pretty little value added, plus, I am sure it also would
increase P3 price dramatically. But there is a "workaround"! I discovered
Reversed Beacon Network and bunch of nice people who actually put very nice
SDRs with Skimmer online and report on DX cluster every station that did CQ
or TEST in their CW transmission. I use N1MM as my rig control software and
it has band maps where all the cluster stations appear as they are reported.
It is almost like having your own skimmer without all the hassle!
73,
Igor, N1YX

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David Gilbert

Re: using P3 and Skimmer

In reply to this post by Joe Subich, W4TV-4

OK ... I was wrong about how easy it would be to do. I still find it
difficult to believe that any of us should need two different pieces of
hardware to accomplish what is basically the same job.

Dave AB7E

On 8/28/2011 6:22 PM, Joe Subich, W4TV wrote:

>
>> The upcoming KX3 will have buffered I/Q outputs, though, so clearly
>> it could have been accomplished without undue cost adders. In my
>> opinion, it would have made far more sense to include it in the P3.
>
> The circuit of the P3 and the KX3 are massively different. If you had
> bothered to read the P3 manual and study the block diagram/circuit
> description you would not have made such a ridiculous statement.
>
> The P3 does not create audio internally *at all* - to generate I/Q
> would require essentially duplicating the P3's entire "IF" along
> with a separate controller to maintain independent tracking frequency
> control, an independent "wideband" I/Q audio output and digital to
> analog converters.
>
> 73,
>
> ... Joe, W4TV
>
>
>
> On 8/28/2011 8:08 PM, David Gilbert wrote:
>>
>> Hi, Doug.
>>
>> It cannot be done without the addition of some other SDR hardware, such
>> as an LP-Pan or SDR-IQ or Softrock.
>>
>> I publicly, privately, and unsuccessfully lobbied for well over six
>> months prior to the introduction of the P3 for Elecraft to include
>> buffered I/Q outputs in it so that it could be used with third party SDR
>> software like CW Skimmer. The fact that it doesn't is why I don't own
>> one and instead bought an LP-Pan. There are so many interesting things
>> that can be accomplished with SDR applications that I don't want to be
>> without that capability, and in my opinion buying two sets of hardware
>> to do essentially the same thing is an unnecessary redundancy.
>>
>> The upcoming KX3 will have buffered I/Q outputs, though, so clearly it
>> could have been accomplished without undue cost adders. In my opinion,
>> it would have made far more sense to include it in the P3.
>>
>> 73,
>> Dave AB7E
>>
>>
>>
>>
>> On 8/28/2011 2:51 PM, DOUGLAS ZWIEBEL wrote:
>>> I have noted on the P3 panadapter page from Elecraft, that one of the
>>> "features" or uses is cited as
>>>
>>> http://www.elecraft.com/P3/p3.htm (bullet #11)
>>> Buffered IF output to drive other equipment (CW Skimmer etc.)
>>>
>>> Can anyone describe for me just how this is specifically
>>> accomplished for
>>> use with Skimmer? I don't see any references to "how to hook it up
>>> with
>>> Skimmer" anywhere in the P3 user's manual, while I see a lot of
>>> documentation for "how to" with LP-Pan.
>>>
>>> Thanks,
>>> de Doug KR2Q
>>>
>>> K3 SN: 295, 822
>> ______________________________________________________________
>> 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
>>
>

Guy, K2AV

Re: using P3 and Skimmer

One is enough. If skimmer is really needed, and you want the panadapter and
the ability to drive various programs, you get LP-Pan instead of a P3.

A P3 was made so someone with ONLY a K3 and a P3, WITHOUT a PC, could have a
panadapter. The P3 was not designed as a do-all for all things SDR.
Elecraft may get around to some add-ons, like IQ output from a P3 or some
such, but those are business decisions. A K3 had a very clear, specific
intention to begin with, which it brought to life very nicely.

73, Guy.

On Mon, Aug 29, 2011 at 2:34 AM, David Gilbert <[hidden email]>wrote:

>
>
> OK ... I was wrong about how easy it would be to do. I still find it
> difficult to believe that any of us should need two different pieces of
> hardware to accomplish what is basically the same job.
>
> Dave AB7E
>
>
>
> On 8/28/2011 6:22 PM, Joe Subich, W4TV wrote:
> >
> >> The upcoming KX3 will have buffered I/Q outputs, though, so clearly
> >> it could have been accomplished without undue cost adders. In my
> >> opinion, it would have made far more sense to include it in the P3.
> >
> > The circuit of the P3 and the KX3 are massively different. If you had
> > bothered to read the P3 manual and study the block diagram/circuit
> > description you would not have made such a ridiculous statement.
> >
> > The P3 does not create audio internally *at all* - to generate I/Q
> > would require essentially duplicating the P3's entire "IF" along
> > with a separate controller to maintain independent tracking frequency
> > control, an independent "wideband" I/Q audio output and digital to
> > analog converters.
> >
> > 73,
> >
> > ... Joe, W4TV
> >
> >
> >
> > On 8/28/2011 8:08 PM, David Gilbert wrote:
> >>
> >> Hi, Doug.
> >>
> >> It cannot be done without the addition of some other SDR hardware, such
> >> as an LP-Pan or SDR-IQ or Softrock.
> >>
> >> I publicly, privately, and unsuccessfully lobbied for well over six
> >> months prior to the introduction of the P3 for Elecraft to include
> >> buffered I/Q outputs in it so that it could be used with third party SDR
> >> software like CW Skimmer. The fact that it doesn't is why I don't own
> >> one and instead bought an LP-Pan. There are so many interesting things
> >> that can be accomplished with SDR applications that I don't want to be
> >> without that capability, and in my opinion buying two sets of hardware
> >> to do essentially the same thing is an unnecessary redundancy.
> >>
> >> The upcoming KX3 will have buffered I/Q outputs, though, so clearly it
> >> could have been accomplished without undue cost adders. In my opinion,
> >> it would have made far more sense to include it in the P3.
> >>
> >> 73,
> >> Dave AB7E
> >>
> >>
> >>
> >>
> >> On 8/28/2011 2:51 PM, DOUGLAS ZWIEBEL wrote:
> >>> I have noted on the P3 panadapter page from Elecraft, that one of the
> >>> "features" or uses is cited as
> >>>
> >>> http://www.elecraft.com/P3/p3.htm (bullet #11)
> >>> Buffered IF output to drive other equipment (CW Skimmer etc.)
> >>>
> >>> Can anyone describe for me just how this is specifically
> >>> accomplished for
> >>> use with Skimmer? I don't see any references to "how to hook it up
> >>> with
> >>> Skimmer" anywhere in the P3 user's manual, while I see a lot of
> >>> documentation for "how to" with LP-Pan.
> >>>
> >>> Thanks,
> >>> de Doug KR2Q
> >>>
> >>> K3 SN: 295, 822
> >> ______________________________________________________________
> >> 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
> >>
> >
> ______________________________________________________________
> Elecraft mailing list
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N8LP

Re: using P3 and Skimmer

In reply to this post by DOUGLAS ZWIEBEL

Correct Jack. Just a couple additional comments...

LP-PAN has more than enough isolation, but we recommend the optional
preamp (mounts inside LP-PAN) to overcome the total losses of the K3
buffer and the hybrid splitter in the P3.

FWIW, I have measured the isolation of the P3 splitter, and it is
considerably lower than 30dB. If using a SoftRock, I would consider it
imperative to use a Z10000 or similar buffer. It would also make sense
to use one of your low noise preamps ahead of the Z10000 if weak signal
decoding in CW Skimmer is important. I would set the gain of the preamp
at about 10dB, and the buffer at about 0dB.

73,
Larry N8LP

On 8/29/2011 12:00 PM, [hidden email] wrote:

> Date: Sun, 28 Aug 2011 20:42:04 -0400
> From: Jack Smith<[hidden email]>
> Subject: Re: [Elecraft] using P3 and Skimmer
> To:[hidden email]
> Message-ID:<[hidden email]>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Don:
>
> I recently had a question from a prospective customer for a Z10000B
> buffer amplifier about the need for additional isolation if a Softrock
> is used with the P3's splitter IF output.
>
> I can't find a spec for the P3's isolation between the IF output port
> and the IF Input, but 30 dB isn't a bad estimate for a 3 dB hybrid
> splitter.
>
> Typical local oscillator leakage out of a Softrock is -40 dBm, so a -70
> dBm signal (approximately) will be injected into the P3's input if a
> Softrock is connected to the P3's IF out port. This will appear as a
> spurious pip on the P3's display at around -70 dBm.
>
> The LPPan has isolation and it's leakage is not a problem when used in
> this fashion. But, I believe a Softrock will require additional
> isolation, on the order of 60 dB or so, in order to be useful without
> injecting a spurious pip into the P3.
>
> Jack K8ZOA
>

Edward R Cole

Re: using P3 and Skimmer

In reply to this post by DOUGLAS ZWIEBEL

After a lot of research and questions to Elecraft and others, I
decided to go with two LP-Pan for my dual-polarity diversity-Rx
system that is also called an adaptive polarity system.

I chose the install the LP internal preamp option since I will be
doing eme level signals. The LP-Pan interface nicely with the
emu0202 soundcard for single receiver work and with the Delta-44 for
dual receiver tasks. In the later DSP is done by Linrad sw fed by
the Delta-44. details with block diagram:
http://www.kl7uw.com/LINRAD.htm

I outline how I slaved one of the LP-Pan to the xosc in the other so
they would be phase locked together, and how I exported the IF from
the sub-Rx in the K3.

73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ 500 KHz - 10-GHz www.kl7uw.com
EME: 50-1.1kw?, 144-1.4kw, 432-100w, 1296-60w, 3400-?
DUBUS Magazine USA Rep [hidden email]
======================================

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Guy, K2AV

Re: using P3 and Skimmer

Certainly looks good from here....

73, Guy.

On Tue, Aug 30, 2011 at 4:22 PM, Edward R. Cole <[hidden email]> wrote:

> After a lot of research and questions to Elecraft and others, I
> decided to go with two LP-Pan for my dual-polarity diversity-Rx
> system that is also called an adaptive polarity system.
>
> I chose the install the LP internal preamp option since I will be
> doing eme level signals. The LP-Pan interface nicely with the
> emu0202 soundcard for single receiver work and with the Delta-44 for
> dual receiver tasks. In the later DSP is done by Linrad sw fed by
> the Delta-44. details with block diagram:
> http://www.kl7uw.com/LINRAD.htm
>
> I outline how I slaved one of the LP-Pan to the xosc in the other so
> they would be phase locked together, and how I exported the IF from
> the sub-Rx in the K3.
>
>
> 73, Ed - KL7UW, WD2XSH/45
> ======================================
> BP40IQ 500 KHz - 10-GHz www.kl7uw.com
> EME: 50-1.1kw?, 144-1.4kw, 432-100w, 1296-60w, 3400-?
> DUBUS Magazine USA Rep [hidden email]
> ======================================
>
> ______________________________________________________________
> 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
>