DSP in the FT-891 is great for the mobile environment. I can filter out noise and just hear voice. Almost like listening to FM !
Ran an 857 for (more than 10) years in the mobile with the ATAS-120A and it worked well, but the 891 is even better. Don’t care about 2m/70cm anymore, since there is little activity on those bands around here.
Only complaint I have with the 891 vs the 857 in the mobile is that the 891 doesn’t offer as wide a menu selection to be assigned to the A/B/C buttons as the 857 did. Can’t assign RF power output to a button on the 891 like I could on the 857, unless I haven’t found out how (operator error is always a possibility).
Always had good results from the ATAS. My K-400 mount is grounded/bonded to the vehicle frame, and the ATAS has always worked well. The ease of installation/operation of the ATAS with a Yaesu radio is much more simplified over other screwdriver antennas. Just assign the tune function to one of the front buttons, and you don’t have to take your eyes off the road. I don’t care about the lack of 75m ops, so the ATAS is not a compromise for me. 40 and 20 are the go-to bands for me when mobile.