{HEAD ~ Other environmental conditions} that interfere with {TAIL ~ the transmitting and receiving signals} may further bear on the values of V1 and V2 
{ HEAD ~ Other environmental conditions } that interfere with { TAIL ~ the transmitting and receiving signals } may further bear on the values of V1 and V2
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH