WSJT-X Split Operation and Why Use It

In FT-8, Software by K0PIR20 Comments

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I’m going to make the case for using Split Operation in the WSJT-X program. Recently I took a poll on the WSJT-X Facebook page and got some interesting results. Almost twice as many Hams use “Fake It” than “Rig” for Split Operation. There are still many that use “None”.

Modern HF transceivers are capable of using “Rig” for Split Operation, however most Hams end up using “Fake It” because of either radio problems, timing issues or just plain simplicity. I have been using “Fake it” for a long time and just recently revisited using “Rig”. Both work very well. Note: If you are using the Icom 7300 or 7610 and Ham Radio Deluxe for the Rig in WSJT-X, you will have to use “Fake It” for Split Operation.

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Split Operation Explained

The Split Operation that I am talking about here is the setting on the Radio tab in WSJT-X. For split we have three choices, Fake It, Rig or None.

There is another split method that we can use when trying to make contacts and that involves using the option in WSJT-X to “Hold TX Frequency”. More on that later.

What is Split Operation and why is it useful?

Significant advantages result from using Split mode (separate VFOs for Rx and Tx) if your radio supports it. If it does not, WSJT-X can emulate such behavior. Either method will result in a cleaner transmitted signal, by keeping the Tx audio always in the range 1500 to 2000 Hz so that audio harmonics cannot pass through the Tx sideband filter. Select Rig to use the radio’s Split mode, or Fake It to have WSJT-X adjust the VFO frequency as needed, when T/R switching occurs. Choose None if you do not wish to use split operation. – WSJT-X Manual

The Case For Using Split Operation

I think it’s important to use Split Operation in the WSJT-X settings and here’s why.

Let me show you what I found out from operating PSK31.

If you ever operated PSK31 you may have noticed when moving too far off center that the power output level will go down. To compensate for this, some software (WinWarbler) offers the option to optimize or set the transceiver frequency to achieve optimal offset.  It will shift your frequency for you.

This is basically what the Split Operation will do in WSJT-X, but WSJT-X does it on the fly. It uses the optimal offset and puts your TX audio in the range of 1500 to 2000 Hz automatically for you and leaves the RX frequency alone. Nice!

With WSJT-X and using “None” you may not see the loss of power if transmitting out of 1500 to 2000 Hz like when in PSK31 mode, but there is the risk of creating IM within the TX passband.

If I look at it in terms of my experience with PSK31, I’m going to naturally want to use Split Operation in WSJT-X. I’ll have a cleaner signal and I think it increases my chances of making the contact. Also, a cleaner signal makes everyone around me happy.

Holding the TX Frequency

The other split reference we here about is using the option, “Hold TX Frequency”.

wsjt split operation tx hold frequency

I always use “Hold TX Frequency” when calling CQ, because I don’t want to lose my TX frequency.

Some experienced users exclaim, “Don’t call me on my transmit frequency”. It’s not a hard and fast rule, but makes sense, especially in a DX pileup situation.

If you select the option “Hold TX Frequency” in WSJT-X to hold the TX frequency and then place your red TX indicator in a clear spot on the waterfall (wide graph) it may help you get the DX station that everyone is calling.

wsjt-x waterfall spilt

The reasoning behind this: Others will be calling the DX station on the DX stations TX frequency (simplex). So instead of getting caught up in the pileup, try this split method.

I know many Hams use this method, because when I call CQ others respond off of my TX frequency.

I have to admit though, to this date, I’ve been disappointed. I don’t know why, but I have better success using simplex and calling a station on it’s TX frequency. I still think split is worth trying when calling a DX station and I’ll continue to try it for North American stations too. Just my 2 cents on that subject.

Conclusion

I encourage everyone to try using Split Operation, either “Rig” or “Fake It”. It may take a little getting used too. If it doesn’t work for you then use “None”. It’s not the worst thing, especially if you don’t use excessive power. You could also try to stay in the 1500 to 2000 Hz range too.

I hope you find this information useful. Thank you for coming by and I hope to hear YOU, on the air!

So how do you use the “Hold TX Frequency” option?

If you have any questions or comments, please post them below. Your experience will help someone else. I’ll do my best to answer questions and reply.

73,

Rich, K0PIR

Sources:

FT8 Hinson Tips for HF DXers

WSJT-X

Frode, LA6VQ in QRZ.com Forum

UPDATE: Very informative comments below. I just want to clarify using Split Operation as mentioned first. If using Rig or Fake It, it just shifts your TX frequency to put your TX in the sweet spot of 1500 to 2000 Hz. When using it, if your TX and RX indicators are lined up on the same frequency in the wide graph, you will still not be running the traditional split mode, it is simplex, ie. calling on the TX frequency of the other station. Thanks so much for the very informative comments.

Comments

  1. Hi Rich,
    I have 7610, WSJT JT alert. Works ok but VFO changes from USB-DATA to USB by itself sometimes. Any ideas?

    Bil w9LR

    1. Author

      Hi Bill,

      Nice to hear from you and thank you for commenting.

      In WSJT-X try Data/Pkt. for MODE.

      You may also want to use Fake It for Split Operation in WSJT-X.

      See if that works.

      Rich, K0PIR

  2. I have been using Rig with my 7610 and notied when it is time to transmit, the radio seems to start, resets and starts again and continues. I can hear the relays click twice. I will try fake it and see what happens. Enjoyed the conversation about split mode. It will make me a better operator. Going to use Hold Transmit.

    I sure wish we could post picture here at your website.

    Brad
    N6GR

    1. Author

      Hi Brad,

      Yes, I have used fake it a lot and it works very well. The siftware will alter the TX freq. on the radio.

      Try it.

      Rich, K0PIR

  3. Thanks for all your help, Rich. I have done everything you suggested, and I am unable to make WSJT-X work correctly. I get one thing working, and another thing messes up. I have tried v. 7, 8, 9 and still, something is not quite right. The latest problem is switching out of USB-D goes out to USB when it stops transmitting. I have tried many different ways. I have probably spent 20+ hours trying to make it work.

    Thanks for all your effort. I am not one to give up, but, I am tired of trying.

    73

    Deryl, WB4QIZ

    1. Author

      Hi Deryl,

      Thank you for commenting, I am sorry to hear that, but it has happened to me too. After a while go back and try it again. Sometimes when I take a rest, I figure out what the problem is later.

      Today I am not using Ham Radio Deluxe as the rig. I have the Icom 7300 as the Rig in WSJT-X and I can use either Fake it or Rig for Split Operation. I can just leave Ham Radio Deluxe Logbook open and JT-Alert will log into it automatically. There’s a article and video here. I don’t know if you’ve attempted JT-Alert, but it is a worthwhile program for Hams who use WSJT-X a lot.

      I have not Failed:
      I have only discovered 10,000 ways that don’t work.
      Thomas Edison

      Hope to hear your on, take care and 73.

      Rich, K0PIR

  4. Hi Rich . Having trouble getting a copy of Ham radio deluxe to match my Icom 7300 ,There are no old copies ,just new available, Are Canadians cut off? Tnx for the great job you are doing, Bob VA3RE

    1. Author

      Hi Bob,

      Nice to hear from you and I certainly hope not, hi.

      I believe you can download the last free version here.

      It doesn’t have the Icom 7300, but there is a workaround. Just use a different radio (7700) and change the CI-V address and make it the 7300s which is 94.

      I hope this helps.

      Rich, K0PIR

  5. I did what you said above: however, the radio jumps out of the USB-D when transmitting to USB on 14.074

    I am using the 7300, on the WSJT-X, on settings, the Radio: Rig is Ham Radio Deluxe, Network server is blank, Mode: I have tried all three, None, USB, and Data/pkt, and the rig jumps out of USB-D to USB when transmitting or when it stops transmitting, it jumps out of USB-D to USB.

    Any suggestions?

    Thanks you for all you help.

    Deryl, WB4QIZ

    1. Author

      Deryl,

      Yes, use Data/Pkt for mode. Use Fake it for the Split Operation.

      When using Ham Radio Deluxe for the Rig in WSJT-X I had problems too when using Rig for Split Operation. Use Fake it and it’ll be good.

      Thanks for commenting and let me know.

      Rich, K0PIR

  6. Rich,

    I am using the Icom 7300, HRD, and WSJT-X with FT8. Audio with Codec, I have followed your instructions with the one USB cable. I get a green signal when I press the button and red with PTT. My problem is I get little power output. I followed all the internal radio connections on the 7300. I am getting signals coming in. I can call CQ and still very little power output. I have the pwr set at 100 watts on the radio and trying to control the slider on the software cannot make the power go higher.

    73,

    Deryl, WB4QIZ

    1. Author

      Hi Deryl,

      Nice to hear from you and thanks for commenting.

      In the radio, look and see if your USB MOD Level is around 40%. You can increase that to increase power. DATA MOD should be USB.

      If you’re using Windows go into the Sound and Playback Devices. Look for the USB Audio CODEC and open it. Go to the Levles tab and see what it is set to. 30 to 50 is a good starting place.

      Set the Slider to 1/2 and try the Tune button. You should have plenty of power. I adjust mine in Windows and then WSJT-X. I leave the radio alone most of the time. Once you get it set, you won’t have to touch those again.

      If you still need to decrease power you can turn down the RF Power on the radio.

      I should do another video on this and WSJT-X. Thanks for the question and I hopes this helps.

      Let me know,

      Rich, K0PIR

  7. Hi Rich,

    Thanks for a nice article as always.

    I always work split and ALWAYS call the DX off his channel. I have had astounding success with this and am surprised that you have not. Okay, I may have to call for over 10 mins, but I invariably snag ’em. I have also started to stop sending the line with my locator. It makes for much quicker QSOs.

    73 de Guy G4DWV 4X1LT

    1. Author

      Hi Guy,

      Nice to hear from you and thank you for commenting.

      It is strange, but it seems like simplex works better for North American stations. How can it be??? With the software the QSO partner will see my callsign in the RX window just as if I was calling him on simplex. It seems very odd.

      I am wondering if it has something to do with the software and timing. Maybe simplex will be seen 1st by the software if “Call 1st” is checked on the receiving station??? It is a mystery.

      When 20 Meters is so very busy it is sometimes hard to find a clear spot, so it seems using simplex is the only way. I’ll have to look into that some more and see if I am missing anything. How do you find a clear spot or do you go simplex too?

      I appreciate your taking time to comment. I will continue to try it more and see. Maybe it is just a quirk and over the long run it will even out for me.

      I hope to see you on the air.

      Best 73,
      Rich, K0PIR

  8. Rich, I have found that with the 7300, if you use “rig” for the split and you change the band you are operating on, as an example 40 meters to 30 meters, your receiver changes to the frequency that is that your switch to automatically with WSJT-X, but your second VFO does not change frequency on the transmit. The 7300 will try to transmit on 40 meters when you change to 30 meters for receive. Do not have my 7610 set up for WSJT so I do not know if it does the same or not. When you check the “fake it” box, the 7300 switches both transmit and receive correctly. 73, Ray AA4EZ

    1. Author

      Hi Ray,

      Nice to hear from you and thank you for the comment. I was just on another forum last week and was mentioned the same thing about the 7300. I would have to make sure and sync the VFOs when changing bands. It was a little cumbersome and that’s why I started using Fake It.

      I tried “Rig” with my 7610 and it worked perfectly. I am using The Icom 7610 for the Rig in WSJT-X. Using Ham Radio Deluxe for the Rig in WSJT-X still causes problems for me.

      I was going to go back and test it with the 7300 and using the Icom 7300 as the rig just to see if something had changed.

      Thank you for commenting and thank you for the reminder about the 7300.

  9. I am very impressed with FT-8 and us it a lot. However, I don’t like using split with FT-8 for the following reasons.

    1. When using split the required bandwidth is doubled. When not using split both sending and receiving stations use the same frequency and 50 Hz bandwidth. When using split each station is using 50 Hz for a total bandwidth of 100 Hz.

    2. Split causes interference. A station calling CQ picks a clear frequency and the answering station blindly picks a different frequency that may not be clear for the calling station. This creates the possibility of interference to other stations on those frequencies. This often occurs when a desired DX station calling CQ is simultaneously called by multiple stations.

    When the band isn’t busy, split works fine. When it is very busy split doesn’t work well, creates interference and uses double or more of the bandwidth.

    FT-8 is amazing. I have called CQ and then simultaneously copied and worked 2 or more stations answering on the same frequency.

    It will be interesting to see how FT-8 works out on field day. My guess is that if propagation is good the existing 20 Meter 3 KHz FT-8 window will expand to about 13 KHz or more, perhaps from 14.070 to 14.083 MHz.

    Earl, N7EP

    1. Author

      Hi Earl,

      It’s nice to hear from you and thank you for commenting.

      If I understand you correctly you are referring to just plain old spilt and not Split Operation, ie. Rig and Fake It.

      When the band isn’t busy, split works fine. When it is very busy split doesn’t work well, creates interference and uses double or more of the bandwidth.

      That’s pretty much how I see it. When the band is so busy it’s hard to find a clear spot to put my TX indicator, hi!

      Thank you so much and I appreciate your taking time to comment.

      I hope to hear you on the air.

      Best 73,
      Rich, J0PIR

  10. Rich
    Doesn’t using split tie up twice as much band width??
    The FT8 band portion is already crowded most times
    Steve
    KK6NTL

    1. Author

      Hi Steve,

      Nice to hear from you and that’s a very good question. Using Split Operation, there’s no question is doesn’t, but I think you are referring to plain old split when making QSO’s. According to the experts, the short answer is no. See section 9.3 in this Hinson Tips for HF DXers.

      Here’s his explanation:

      Each party to a QSO transmits in a different period. Even and odd periods are orthogonal or independent, and should be considered separately. Within each period, each party is using one thin slice of spectrum, just 50 Hz wide. After they end their transmission, their transmit frequency is then released for anyone else to use. See Appendix E for a more elaborate explanation.

      What do you think?

      Rich, K0PIR

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