The antenna that comes with the ACK E-04 is the E-04.8 which is designed for transmitting on 121.5 MHz and 406 MHz.
The ACK-E-04 is spec'd to output a maximum of 23 dBm at 121.5 MHz. That's 200 mW and is 50 times less than the typical 10 W aviation communications transceiver. So the E-04.8 may not be designed to accommodate the output power of a comm radio.
I can't find any document showing the frequency response of the E-04.8. If it has a tight bandwidth (which I doubt but do not know) on VHF, the SWR might swing high in the comm freqs.
There is no harm in using the antenna for receive only
with a communications transceiver.