antenna always goes up

1978 vette:  Every time  I start  the ignition my  power  antenna  rises,  does not matter  if  radio  is  on or  off.  Any suggestions for antenna to work only when radio is on?  thanks  zzzs

More info. Is it factory radio and antenna? Most likely problem with antenna relay or relay wiring under the console. If aftermarket antenna, which it probably is(if you have a chrome antenna bezel on your 78 it is)sounds like it is wired into the ignition. Some antennas have a wire that goes to a hot "antenna lead" on the radio to control raising it when the radio is on. Perhaps  the antenna got wired to the power lead to the radio instead of the antenna lead.   Mike