True
When I relied on radios for my living (tow truck), I had separate radios for base and mobile freqs. (I used Mot. Maxtracs...insanely good reception)
One idea: Try having your DPS in a dedicated list. Have both channels in, and set delay to 0, so the radio will immediately resume after one or the other quits transmitting.
And, also that is how the actual DPS radios are set up: The units can only hear their base. When they key up, their radio TXs on one, and as soon as they un-key the radio goes back to RX on the other.(Same as a conventional repeater setup, sans repeater) The units can't hear each other, and on busy nights, we would hear them key up over each other, not knowing that another unit was also calling dispatch.
Some troopers actually read their Spectra manuals and knew how to set up priority scan so they could hear other nearby troopers' traffic.
For car to car chatter, they move to a dedicated car to car channel, or locally, use the local 800 county system, where they have both dispatch simulcast(saves me $500 for digital radio...for now) and car to car TG.
One thing that will help TREMENDOUSLY is a 5/8 wave VHF whip. That will work MIRACLES for hearing the mobiles. Especially if you're used to a ducky.
Rich