Spengler OXYFROG Manuel Utilisateur page 57

For transmitters rated at a maximum output power not listed above, the
recommended separation distance d in meters (m) can be estimated using the
equation applicable to the frequency of the transmitter, where P is the maximum
output power rating of the transmitter in watts (W) according to the transmitter
manufacturer.
NOTE 1: at 80MHz and 800MHz, the separation distance for the higher frequency
range applies.
NOTE 2: these guidelines may not apply in all situations. Electromagnetic
propagation is affected by absorption and reflection from structures,
objects and people.
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