Sennheiser SpeechLine Digital Wireless Series System Documentation page 39

▷ When using multiple AWM 2/AWM 4 antenna wall mounts, make sure
that the distances between all antennas are equal:
►
▷ If possible, position the antennas so that there is a direct line of sight
(without obstacles) between the transmitters and the antennas.
►
Recommendations on antenna mounting
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