Tuesday, October 26, 2021

The art of working split to contact a DXpedition.

 

Contacting 7P8RU

Yesterday afternoon while on 20m I noticed a large gathering around 14.040.  After a little investigating, I found it to be the 7P8RU DXpedition from Lesotho located in South Africa. The team were excellent CW operators and this made for a very organized pileup. As I listened to find out how they were working the pileup I found that as always operators trying to contact 7P8RU on their calling frequency.  With most if not all DXpeditions they operate split, meaning they call CQ on one frequency and listen on another. Their listening frequency can vary from 1kHz to 5kHz span. 

I find it best to listen to the DX station and also those trying to contact the DX station. This is done to learn how the DX station is working "the pileup"..... those who are trying to make contact. Most if not always the DX station has a pattern on how they contact calling stations. Other times they indicate specific regions they only want to contact.  It's best to listen first and find out the DX's rhythm, and also if they are working a region of the world that you are not in. This avoids you calling not getting answered and the DX station wondering why you're not listening to instructions.  This just brings about frustrations at both ends. 

Now down to the nitty-gritty of making contact! Once you have listened and found out the DX rhythm and that he is working stations in your part of the world, it's time to jump in the fray. But wait, how does one listen to both the DXpedition and perspective contact stations, who are 1-4 kHz away? This is where rigs with 2 independent receivers come in very handy. The 2 independent receivers allows you to hear VFO A and VFO B at the same time or the DX and those who are trying to contact them.  In my case I use headphones with VFO A in my left ear and VFO B in my right ear. 

They do say that a picture is worth a thousand words....and with DXpeditions this is also very true.  It's great to hear both sides but adding a visual representation is fantastic!  This is done with a radio that has a spectrum scope. Now you are able to hear and see each station the DX is working. As the DX either moves up or down the band, you can fit your signal in the pathway and toss out your call and see if you are heard. 

The Icom 7610 has all the above-mentioned bells and whistles, as do many other HF and SDR rigs. The picture above is a screenshot of my 7610 setup to work 7P8RU. I have turned on "Dual watch" this allows me to hear both VFO A (main) and B (sub) Split has been turned on, so I transmit on VFO B and not on top of 7P8RU on VFO A. 

On the spectrum scope, the red M is the main VFO A, and it is set on 7P8RU's calling frequency. The crowd of signals to the right (between M and S) are those calling the DXpedition station. The green "S" is my sub VFO marker and tells me where my transmit signal will be. 

One nice thing about the scope, once 7P8RU has contacted a station, most times you can see this station visually answering the DX station. By watching this interaction you get an idea of how the DX station is working the pileup.  The above picture shows the scope giving a band slice of 100 kHz and you can see t FT8 to the far right and toward the bottom of the band other CW signals. When working the DXpedition I have the scope set to a narrow slice of the band, so I can get a better picture of the pileup and who is being worked by the DX. 

It's great fun to work these stations when you can hear them, and it gives you a good workout on learning your radio and what it can do. In my case 7P8RU was contacted and is in the log! 

8 comments:

  1. Well done Mike, the dual receive function on your radio is excellent for that task. Wish I had an extra one in my IC-7300. It would make things a lot easier. Congrats on working them. So far I worked 7P8RU only on 10m I believe. Should make another effort on other bands now. And hope to work them on 60m which is one of my favorite bands since a few years. 73, Bas

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    1. Good morning Bas, thanks for the kind words, and I was very pleased to contact them. One of the main reasons for me getting the 7610 was the dual receive with 2 receivers. I have a few days of relaxation and I may try to get them in the log on other bands as well.
      73,
      Have a good week.
      Mike
      VE9KK

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  2. Hello Mike, Thank you for the interesting post. The frequency display is a great tool. I once build a simple spectrum analyser for my oscilloscoop to see all the stations on the whole band instandly. Yes, it is great to hear and see the signals. FB. It is great fun and... You also worked 7P8RU. 73, Bert

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    1. Good afternoon Bert very nice to hear from you I hope you are doing well, yes the setup with the 7610 for me is like a dream radio. For sure getting 7P8RU in the log was a bonus!
      73 and have a great week,
      Mike
      VE9KK

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  3. Hi Mike, if you work split then the chances are really much higher. Really nice DX Mike. Well done. With FT8 I always work split. 73 Paul

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    1. Good afternoon Paul very nice to hear from you, I was very happy to make the contact! Yes operating split is the way to go for sure.
      Have a nice what is left of the week Paul,
      73
      Mike
      VE9KK

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  4. WHY did I sell my 7610 Mike??? It's the best out there, bar none!

    73, Tom.
    www.M7MCQ.com

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    1. Good afternoon Tom, yes we all have sold an item that later we shake our head wondering why we did it. I have had lots of those moments in my ham career.
      73,
      Mike
      VE9KK

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