Paul Remde wrote:
Beyond whether it is OK to do - it is also important to consider whether it
will work well when needed. The rubber duck antenna is for 118 to 136 MHz
while the ELT that Ron asked about transmits on both 121.5 and 243.0 MHz
simultaneously. It is important to use an antenna that will transmit on
those frequencies well in an emergency.

To be honest, I suspect some of us are giving a bit more consideration
to what is minimally necessary to meet the SSA rules and FAA
regulations, than we are to how well it might ultimately work if it is
ever actually needed...

Marc