CW Skimmer – Quadrus SDR

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What is a CW Skimmer?

A CW Skimmer is multi-channel CW decoder and analyzer by Alex, VE3NEA. You can read about this great tool and his other works on his website:

A great tutorial is available from Pete, N4ZR as well:

Go ahead, and look at the links if you are not familiar with the topic.

How to connect the CW Skimmer and the Quadrus SDR ?

The CW Skimmer is accepting signals from radio receivers. The traditional hardware radio can be connected through a sound card audio input to the software, and the CW Skimmer software can remote control the receiver on CAT. The bandwidth, in this case, is limited to the usual 3 kHz of typical HF radios.

However, the CW Skimmer software can handle a couple of SDRs too, and can accept higher bandwidth signals from them. Some of the SDRs on the market can also be controlled from software trough their APIs.

Today the CW Skimmer – Quadrus SDR connection is not supported directly by the CW Skimmer. Thus, we have to use the simple audio interface connection. This limits the analysis bandwidth to 3 kHz. Because the SRM-3000 SDR receiver is software too, we can use a virtual audio cable to connect to the CW Skimmer. I’ve used the VB-Cable A&B from VB-Audio Software for my tests. A single connection is free for non-commercial use.

Decoding calls in the 20 m band

Yesterday, I had a chance to use one of the remote stations with TeamViewer. It is located in the country side with a simple inverted-V shaped G5RV wire antenna. I found a spot around 14.025 MHz in the CW band. There were a lot of stations in the 3 kHz bandwidth. The outcome of only a couple of minutes of recording can be seen below with the call signs collected by the CW Skimmer.


Further improvements with server version CW Skimmer

There is another software from Alex called CW Skimmer Server. This application can handle up to 192 kHz bandwidth in seven ham radio bands. The SDRs can be connected with a 3rd party driver. We are looking for interested programmers to provide a driver to CW Skimmer Server based on the TCP/IP remote control interface of the SRM-3000 SDR software receiver.

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11 thoughts on “CW Skimmer – Quadrus SDR”

    1. Heard and saw an English station calling by using another remarkable communication software MixW3.
      It’s difficult to find radioteletype stations in the lower frequencies this evening.
      Distant station may be found on the higher frequency bands during daylight.

        1. I have received all continents using JT65 mode. Above all there is activity frem even Antarctica. The other day the Japanese Research Base was active, today a R1ANR Russian research base station was heard in Europe.

  1. BPSK31 is one of the most popular mode on ham radio bands since telegraphy exams are not compulsory in most countries. It seems RTTY is mainly used during contests and it is preferred by old boys who has had this possibility beside Morse telegraphy an AM after WW II. BPSK31 is the everyday digital conversation mode which csan be used between distant stations. There are dedicated frequencies in each band plans of IARU regions.
    See: (Can be printed onto an A4 size sheet.) and to print a larger sheet of paper.

  2. I think this is one of the most significant info for me.And i am glad readnig your article. But want toremark on some general things, The site style is ideal, the articles is really nice : D.Good job, cheers

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