First you have to open the back of our radio removing the screws marked in the pics below:
Open and find a stripe of 16 pins, you are on the back of the board, see the red circle on the pic below:
Now, the IF output is the 10th pin from the left, the 6th from the right.
Solder a 100pf capacitor to decouple the radio from the sdr and to prevent sdr with bias tee to inject some current.
Add a cable taking the earth from the negative pin of the battery or from other place you like,
and a panel female connector, I choose to use a 2,5mm mono jack, and fix it on one side
You can close the radio now and make a cable to connect the IF out to an SDR, in my case a 2,5mm mono jack male to SMA.
Connect SDR to your PC and open SDR# or other sdr software you like.
According to AOR manuals you have to tune the following IFs, depending on the frequency sintonized:
from 100kHz to 450MHz and from 1500 to 1950MHz IF is at 736,250MHz
from 450 to 1500MHz IF is at 275,450MHz
Below are two examples:
Broadcast FM signals, radio set on 88MHz SDR# on 736,250MHz
TETRA signal, radio set on 463MHz and SDR# on 275,450MHz