John,
My first response to you message bounced. So, let's try again.
I'm betting that the radio power doesn't run the antenna. My '63 has a
switch that runs the antenna is mounted next to the map light. Just checked
the '61 brochure. Yours should be in the same location; just right of the
map light under the dash pad.
Here's a pointer to a photo of your dash. You can see the map light just
above the radio and the switch just above the right-most radio preset
button.
http://www.imperialclub.com/YearbyYear/1961/Brochure/page14-15small.jpg
Hope that helps!
Mark Evans
1963 Imperial Crown Convertible
http://www.io.com/~maevans/MyImperial/index.html
1968 Dodge Polara 500 Convertible
http://www.io.com/~maevans/MyPolara/index.html