UNO5800

hello
i bought your 600mw transmitter and the UNO5800 v4 receiver.
Is the receiver only working with batteries or akkus?
I bought a power adaptor with the output of 9V DC 1,2A. After i turn the UNO5800 on, it continously is beeping.
I tried to turn off the "under-voltage"-function, but in the manual there is only explained to do it with 2 or 3s akkus or batteries.
So my question is: It is right, that there is no possiblity to run the UNO5800 with the adapter which is turning the input (230V) to 9V DC ?
If it is possible, why the UNO5800 is no running right. It only penetrates with a disturbing BEEP-sound which wont stop what every i try to do on the UNO5800.
Best regards