If you are going to use this procedure to work APRS you should have APRS configured on your radio before you proceed. You can use this post to get started.
The Dual Receive Function utilises the Band Home memory and any other frequency either from memory or using the VFO. So the first step is to program the repeater into the Home memory for the Band you are going to use, I will use Band A but you can use either A or B. Setting the Home memory frequency is covered on page 54 of the manual but the steps are:
- Switch to VFO mode and Band A.
- Tune in the frequency you want, and set up any other operating settings you want (PL tones, etc).
- Press and hold V/M MW for over one second. The Memory Write screen appears.
- Rotate the dial to select Home.
- Press DISP Setup. The overwrite confirmation screen appears.
- Rotate the dial to select OK, and press DISP Setup.
One thing to be aware of. When using this for APRS beacons will be transmitted when it is time as determined by the APRS software and the receiver doesn't detect activity regardless of what frequency the unit is actually tuned to. If you get involved in a QSO you may end up transmitting a beacon on the repeater frequency. Not the end of the world, but also maybe something that you don't want to do. An easy way to prevent this is to have the Home frequency stored in a memory location in the other Band (Band B) and have that Band set up to work the repeater. Then by switching to Band B for the QSO the APRS and Dual Receive operations will be suspended until you switch back to Band A.
Another is that if you use APRS Muting from page 59 of the radio APRS manual you won't be able to hear the activity on the home frequency. This is because this is APRS operating band mute and all activity on that Band A or B will be muted. I think we are better off using the voice alert procedure from www.aprs.org anyway.
This may seem a little complicated, but I've used this to operate APRS and have had QSOs with a couple of people and it is easy to do once you have practised a bit. So if you want to operate APRS without dedicating the radio to that, or just want to monitor one repeater while you work another give this a try.
This YouTube video may also help although this video shows setting the "APRS" frequency as the Home station, but I don't think that is the base way to do it.