HP M210 Configuration And Administration Manual page 49

The solution to this problem is to set the two networks to different channels with as great a
separation as possible in their operating frequencies. This reduces crosstalk and enables
wireless clients connected to each M210 to transmit at the same time.
AP 1 AP 2
Channel = 1 Channel = 6
AP AP
Selecting channels
For optimal performance when operating in the 2.4 GHz band, select an operating frequency
that is different by at least 25 MHz from the frequency used by neighboring APs.
Two channels with the minimum 25 MHz frequency separation always perform worse than two
channels that use maximum separation. It is always best to use the greatest separation possible
between overlapping networks.
With the proliferation of wireless networks, it is very possible that the areas of coverage of APs
outside your control overlap your intended area of coverage. To choose the best operating
frequency, select Wireless > Rogue AP detection to generate a list of all APs that operate
near you and their operating frequencies.
The number of non-overlapping channels available to you varies by geographical location,
which affects how you set up your network when multiple APs are present.
Wireless coverage 49