Sunday, September 2, 2012

CW Skimmer, Airplane Cockpits and Ham Radio

Since I was rained out for my antenna work this weekend, I decided to do some DXing.  I am sitting here with CW Simmer running on the Flex 5000. I just finished working KH8/DL3DXX after about 3 hours of watching the pileup build and the propagation improve.  Funny thing is I only made about 6 calls to get in his log book once I started CW Skimmer. 

I have CW Skimmer tied to the second receiver (RX2) in the Flex 5000.  CW Skimmer from Afreet Software ( is a program designed for Software Defined Radios to decode cw signals across a wide bandwidth. In my case about 10 KHz of bandwidth.  The Flex sends its audio and IQ signals to the controlling computer on what is refered to as virual audio cables (VAC's).  These VAC's can be connected to any kind of digital demod software currently available.  A specific feature of the VAC is its ability to be routed as an in phase and quadrature (IQ) pair of signals.  CW skimmer takes advantage of these bradband IQ signals to allow for decode of a swath of signals instead of the narrow band signal that we are used to. 


OK I'll tell you.  With CW Skimmer and my second receiver, I can watch an entire CW DX pile up as it progresses.  I can see the DX station, and decode what he is sending while simultaneously watching the signals of the answering stations(and decode their responses).  By doing so, I can observe how the DX op is progressing through the pile up and plan my attack.  I like to watch the OP to see how far he tends to tune before answering the next station.  This gives me an idea of where to place my station in my waterfall so that evenually he tunes across me.  This method has proven to be HIGHLY effective.  I won't say that I always get the QSO within 6 calls but I don't send for hours and hours trying to work the guy.  It is akin to making a reservation rather than standing in line.  The wait is much less. 

I started off this morning just calling peiodically to see if he would answer.  I sent my call at least 3 dozen times and decided enough was enough..  I kicked off CW Skimmer and started monitoring.  irst thing I learned was propagation was not good enough to hear most of who he was answering.  I monitored until I could see both sides of the QSO and then stalked his responses.  Once I learned how he tended to tune, I put my signal a few signal widths above the last guy he called and sent.  After about the 5th time through, he sent "Q?".  I sent my call again and he responded with my full call and 599.  I sent my response and got "TU" back.  QSO complete!!!  He's in the log!!

So where did the title for this come from?  I have DXlabs running across 2 monitors, PowerSDR and DDutil running in a third and CW skimmer on top.  There are at least  a dozen programs and 500 buttons on the screen.  There are 3 waterfalls including CW Skimmer!  I think back to the old DX60 days and wonder how the heck did I used to make contacts.  It is a different world.

When you are a Little Gun, you can use all the help you can get!!

Until next time

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