[Elecraft] Connecting SDRPlay to P3 IF OUT, to CW Skimmer

Thu May 23 22:44:42 EDT 2019

Peter,
     First, you do not use RX RF out. You should use IF out. You need not 
disconnect your receive antenna. I believe there is a buffer between the 
receiver IF and the connector on the back of the K3, but the splitter 
adds a little over 3 db loss/per output. The buffer amp I added, the 
Clifton Lab amp available from DX Engineering, adds little better 
buffering and just enough additional gain to make up for the losses 
caused by the splitter. You loose NO coverage this way.

     You really do want to use the Win4K3 suite all the time. It will be 
the center for all of your radio to various software communications even 
if you never use the built in features. Please do not stress over 
setting up com ports; it really isn't that hard with a port replicator 
like com0com. There is only one port to worry about, the one real one 
that connects to the radio. You can make that anything you like using 
device manager, but just use whatever your computer calls it. To find 
out what that is just bring up device manger, look under ports. You 
should see a list of com ports. If there is nothing there, you probably 
have only USB ports. If this is the case plug in your USB to serial 
adapter. It will show up as a com port with number. That is what your 
radio will use and you will tell Win4K3 that number. The virtual 
comports you create will remain constant; just write them down so you 
don't forget them and the pairing. Win4K3 communicates through these 
virtual ports, and they will not change. The one real one may change due 
to software upgrades, but it can be changed back in device manager. Now 
you cab connect any software package you want and use a virtual com 
port. If you use logging software, use the same com port as you would 
for your contest logger like N1MM. Since you will use one or the other, 
your logging can alsways be on that com port; this keeps a constant plan 
no matter what you do. And I do the same thing with FLDIGI and WSJT-X. 
My point is pick some com port designators and some configuration plan. 
You can also use this plan with onmirig and whatever you want. 
Hopefully, this whole thing helps.

73,
Barry
K3NDM

------ Original Message ------
From: "Peter Dougherty" <lists at w2irt.net>
To: "Barry" <barrylazar2 at gmail.com>; "Bob McGraw K4TAX" 
<rmcgraw at blomand.net>; elecraft at mailman.qth.net
Sent: 5/23/2019 10:00:14 PM
Subject: RE: [Elecraft] Connecting SDRPlay to P3 IF OUT, to CW Skimmer

>I had an LP-PAN and sound card and could never get them to work very well
>(they're up for sale for anybody who's interested). I don't think I
>understand the whole RX-OUT/splitter/back to RF-in loop. Doing that would
>mean I would have no RX antenna connection, would it not? I use the RX IN
>connection for the feed from my K9AY loop in the back yard. If I used the
>RX-OUT port, wouldn't I then lose my lowband RX antenna?
>
>This is all still very unclear to me. I don't mind buying the Win4K3 suite,
>but the COM port issues are confusing. 99% of the time I won't be using the
>Win4K3 software and associated control. It's only going to be used for CW
>contesting, period. The rest of the time I just use it as a conventional
>radio for CW, SSB, FT-whatever, and RTTY.
>
>  - pjd
>
>-----Original Message-----
>From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On
>Behalf Of Barry
>Sent: Thursday, May 23, 2019 9:10 PM
>To: Bob McGraw K4TAX <rmcgraw at blomand.net>; elecraft at mailman.qth.net
>Subject: Re: [Elecraft] Connecting SDRPlay to P3 IF OUT, to CW Skimmer
>
>You can do that. In fact I did that initially, I now use a Minicircuits Lab
>2 way splitter and an about 6 db gain buffer amp between my K3s and the
>divider. This seemed to give me a bit better spectrum display. You will need
>NO SDR protection as you are using the receiver IF.
>
>I did use HDSDR during one of my early configurations. It just seemed harder
>to set up than what I use now. But, it won't require spending for an LP pan
>and sound card. Hmmm. I think I just got the answer to a question I had
>raised about using the I&Q data available from the K4 USB connector for CW
>Skimmer. I suspect the formats are the same.
>
>Your description at the bottom of your note will work if all you want is
>spectrum display, but to do serious integration like marrying up logging,
>spotting spectrum display CW skimmer and then a contest configuration, you
>are going to need to distribute and receive K3 band, frequency, and mode
>data. Using Win4K3 suite with com0com does make that easy and you could use
>what you describe using a pair of virtual ports.
>Should work well.
>
>73,
>Barry
>K3NDM
>
>------ Original Message ------
>From: "Bob McGraw K4TAX" <rmcgraw at blomand.net>
>To: elecraft at mailman.qth.net
>Sent: 5/23/2019 8:36:06 PM
>Subject: Re: [Elecraft] Connecting SDRPlay to P3 IF OUT, to CW Skimmer
>
>>Why not take the RX OUT of the K3 to a BNC T  and the RX IN of the K3  to
>the other side of the BNC T and with a BNC T  in that path, feed that to the
>SDR receiver.  Then on the K3 press the RX ANT button and both are fed the
>entire band from the same antenna and they are protected during transmit.
>You can use HDSDR and OmniRig to control both the SDR receiver and control
>the K3.  With HDSDR and OmniRig it communicates both ways.
>>
>>Two short BNC to BNC jumpers, a BNC T and a short BNC to the input on the
>SDR is all that is needed.
>>
>>73
>>
>>Bob, K4TAX
>>
>>
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