==
nit --

All Data Items available in this extension provide access to the
   radios physical layer measurements
   
radios/radio's

==
nit --

Radio Biterror Rate Data Item is a mandatory TLV that contains
   information about the radio receivers estimate how often a
   transmitted bit will be received wrong.

Maybe:

Radio Biterror Rate Data Item is a mandatory TLV containing the receiver's estimate of bits incorrectly modified in transmission.

==
question --

The rate here is as a percentage of bits transmitted rather than time period, correct? The text seems to imply per time period in some way, but I'm pretty certain it's actually per bit recieved in this case?

==
question --

The format of the Radio Biterror Rate Data Item is ...
The format of the Radio SNR Data Item is ...
The format of the Radio Signal Strength Data Item is ...
The format of the Radio Noise Data Item is ...

Do these need length fields? It doesn't seem to adding any information?