2.8.3 Single Operator Split Operation

Split operation is when you transmit on a frequency different from the one where you are listening. This is often used when stations have huge pileups like some DXpeditions, or when frequency allocations do not allow people in different countries or IARU regions to make contact on the same frequency. An example is 40 meter SSB between Europe and the USA. Many European stations operate below 7.125 MHz, the bottom edge of the US allocation. When N1MM Logger is controlling a transceiver with split capability, the program enables you to split and "unsplit", to change frequencies, and perform other useful operations.
When used in this manual, the term "split frequency" always refers to the transmitting frequency. The assumption is that you will listen first, either to identify a station to call or a clear listening frequency to use while running, and then set your transmit frequency.

1. Am I Transmitting Split?

There are a number of ways that the program tells you whether you are in Split mode, which can avoid some embarrassing moments or potentially, a citation for out-of-band operation. In the Entry window Split is displayed in the title bar. The receive frequency is always displayed first, and the transmit frequency in parentheses, as in this example.


In the Bandmap, there are two sets of indicators, shown in this example.


You'll notice that the receive frequency is shown in bold blue letters at the top of the Bandmap, and the transmit frequency is shown below it in smaller type. You are also reminded by the indicators for your receive frequency (always blue) and your separate transmit frequency (always red).

Clicking on either the receive or transmit frequencies in the top part of the Bandmap will toggle split operation.

 Running While Split

Some people prefer to be in Split mode while running, in order to use the main tuning knob to tune in calling stations that are off frequency. One drawback is that if you tune your receive frequency outside the tuning tolerance set on the "Other" tab in Config > Ports,Other, the program switches from Run mode to S&P. The way to avoid this is to use Alt+F11 to temporarily lock the program in the current mode. That is, if you press Alt+F11, the program will not automatically change modes when you tune. Press Alt+F11 again to return to normal operation.

2. Setting Split Transmit Frequencies Manually

The easiest way to set a split transmit frequency is to type the desired frequency in kHz into the Callsign textbox in the Entry window, and then hit Ctrl+Enter. Another alternative is to use Alt+F7 to open the Split dialog, type the transmit frequency, and hit Enter. The split frequency may be entered either in full (e.g. 7027), as a difference from the lower band edge (e.g. 27), or as a positive or negative difference from the receive frequency (e.g. +2) . Decimals are allowed (7032.3, or 7032,3 if your regional preferences in Windows use the comma as the decimal separator).

3. Split Mode and Frequencies Set Automatically from Cluster Spots

If you click on a station in the Bandmap which was spotted with a QSX (transmit) frequency specified — in the format "DX PA1T 7095 QSX 7130"), the radio will be put into split mode and the frequencies set automatically. You will be set up to transmit on 7130 (in this example).

4. Resetting to Non-Split Mode

Resetting to non-split mode is done by moving to another frequency or band, using the program to do so. Simply turning the VFO on your transceiver will not do it. You can:

  • Click on another spot or frequency in the Bandmap
  • Click on a non-split spot in the Packet/Telnet window
  • Click on the transmit frequency or receive frequency in the top part of the Bandmap
  • Click on a band button in the Available Mult's & Q's window to change bands
  • Press Ctrl+PgUp or Ctrl+PgDn (which also changes bands)

 Icom Precautions

Icom radios can't report VFO B without being set to VFO B, and don't report whether the radio is in Split mode. To operate split successfully, you need to set and cancel splits solely from the computer. Use Ctrl+Enter or Alt+F7, as above. Only turn Split on/off from the keyboard/program and not on the radio, to make sure it stays in sync with the program.

5. Split Operation Key Assignments

Alt+F7 - Set split frequency or offset from current frequency for the active radio. When hitting Enter or click OK with nothing on the line split will be cleared. Press ESC or click Cancel to exit.

Alt+S - When your rig is in Split mode, Alt+S will reset the receive frequency back to your transmit frequency, but the split mode is preserved. This is used to run a pileup with the rig in split mode. With a radio which has VFO A/B they use the 2nd VFO as an RIT. This is done since many RIT knobs are small or hard to get at, while some find it more natural to use the main VFO to tune in a caller rather than use the RIT. By running split, you can use the main knob to tune in the caller, while your TX frequency doesn't change. The Alt+S acts like an "RIT clear" when you are running split.

This operates on VFO-A only. With Main/Sub radios like the Icom 756/7800 series you can not RX on SUB without receiving on both VFOs. In this case put RX on Main and TX on SUB for Alt+S to work.

"Reset RX freq when running split", an option found on the Entry window's Config menu, is a way of automating the Alt+S function. When this option is checked, the program will automatically do an Alt+S as you log each QSO. This gives you an automated “RIT clear" after every QSO when you are running split.

Ctrl+S - When not in split mode, the first press of this combination puts the radio and program into Split mode. After that Ctrl+S will toggle the RX frequency between the split RX frequency and the RX/TX frequency while maintaining split mode. Application: This was designed primarily to help SSB operators run on 40 or 80mM where split operation is widely used. For example, "CQ CQ de N1MM listening on this frequency (7183) and 7068". Use the Ctrl+S key to toggle between 7183 and 7068 to check for both USA or DX callers.

Ctrl+Alt+S - Toggle Split mode on the radio. 'Split' will be shown in the Entry window.

Ctrl+Enter - Entering a frequency or offset in the callsign with Ctrl+Enter will set a split frequency.

 Using Split - Some Hints

Click on a spot in the Bandmap or Available window. Then look at the Bandmap or the Entry window title bar to see if you are going to transmit out-of-band. If you SINGLE-click on a spot on 40 or 80, and don't see the split indicator, then wait for the station to announce his listening frequency. If he says "listening 214.5", type 214.5 in the Callsign textbox and press Ctrl+Enter - you are then ready to call him.

6. Split mode vs. SO2V

With a dual-receiver radio, the difference between Split mode and dual receive operation can be tricky. If both receivers are on, the radio is set up exactly the same way for split from the VFO A Entry window (listen to the other station on VFO A, monitor your transmit frequency on VFO B, transmit on VFO B ) and for SO2V with the Entry window focus on VFO B (conduct a simplex QSO on VFO B while monitoring the VFO A receiver somewhere else on the band). However, although these two situations are identical on the radio, they are quite different in the logging software. In the split operation scenario, the QSO is logged from the VFO A Entry window, with different RX (VFO A ) and TX (VFO B ) frequencies in the log. In the SO2V scenario, the QSO is logged from the VFO B Entry window with the RX and TX frequencies the same (both from VFO B ).

By changing the transmit VFO from VFO B to VFO A, you can switch to either one of two new situations - split from the VFO B Entry window (listen to the other station on VFO B, monitor your transmit frequency and transmit on VFO A ) or SO2V with the Entry window focus on VFO A (conduct a simplex QSO on VFO A while monitoring the VFO B frequency somewhere else on the band). Again, these two are the same on the radio, but different in the logging software - split logged from the VFO B Entry window with different RX and TX frequencies in the log vs. SO2V logged from the VFO A Entry window.

Because there are four possible logging scenarios but only two different radio configurations, you cannot depend on making adjustments from the radio to get QSOs logged correctly. By default, in SO2V mode with both receivers active, N1MM Logger will assume you are operating in one of the two SO2V modes and will log QSOs using the callsign and exchange from the active Entry window and logging both TX and RX frequencies from the active Entry window's VFO.

It is possible to work and log split mode QSOs in SO2V mode, but it takes care and practice to get it right. In order to work and log QSOs in split while the Logger is in SO2V mode, you must tell the Logger that you are operating split. Since you cannot do this from the radio, you must turn Split on or off from the keyboard/program, using Ctrl+S and Ctrl+Alt+S. You need to take care to do this from the correct entry window (the one whose VFO you are receiving the other station on), and to be aware at all times of which frequency you are transmitting on.

Last Modification: 17 October 2015 10:05:42 EDT by VE3KI.