I didn't disconnect the cable. Using good jumper cables I placed the good
battery in-line with the installed battery. No luck. I forgot my
multimeter so I couldn't check the voltage on the existing battery.

I called the dealer and a new antenna ring is $62. From what I understand,
to install a new antenna ring you remove three #25 torx screws on the
bottom of the column cover and then pry off the top and bottom.

If I have room to put my leg, even gimpy should be able to install a new
ring. The only possible problem is that the steering wheel is not facing
straight ahead and since I can't start the car moving the wheel may be
difficult. I am parked sideways on a parking lot with a small degree of
grading.

If that doesn't work it may be the key. Then I will need to get the car
towed to the dealer and a new key.