HF Radios: Split Mode channels

We'll occasionally have customers with HF radios contact us to ask why a certain memory channel was sent to their radio as a split. It's a good question and isn't terribly difficult to understand once you know the secret. It all boils down to the settings for both "sides" of the radio and checking to make sure they are identical. 

Take a look at the image below. It's a programming file for an Icom IC-7300. The customer wanted to set up channels 2-14 for FT8 operation. Obviously to do that you need to have the radio set up in Data mode. You do this in your RT Systems programmer by checking the box in the "Data Mode" column. This is the same as selecting "LSB-D" via the radio's own menu. When the customer sent the file to his radio though every channel was set as a split. Why would that be? 

The answer is highlighted. By checking the boxes for "Data Mode" but NOT checking the boxes for "Split Data Mode" you are essentially telling the radio "Use LSB-D for receive and normal LSB for transmit." This it is going to result in those channels being set up as splits. The ONLY way most HF radios can accommodate different settings on the TX versus the RX sides is to have the channel up as a split. 

Also notice the small issue on row 2. The selected filter is different in the "Split Filter" column. Even if we fix the "Split Data Mode" issue mentioned above we'll still have channel 2 show up in the radio as a Split because of that different filter. Again, everything must be identical for TX and RX or the radio uses a Split to accommodate the differences.  

The key point to understand is that ALL setting parameters for a given channel must be identical or else the channel will be sent to the radio as a split. This happens automatically when you send data to the radio from your RT Systems programmer.

Now that you know what causes it you can make sure to look out for it as you work on programming you radio.