What causes harsh noise during TX/RX on VHF radio?
If the transmit signal is strong the Signal-to-Noise Ratio is high, which would mean that the noise that you hear is not background white noise filtered through the VHF frequency band. First thing I would look for is an active noise transmitter on the band, which would only be present in a limited set of frequencies. 

Hard to say from behind the keyboard what causes the noise that you hear, suggestions for troubleshooting:


Is the noise present at all Xmit frequencies? 
Does it diminish if you move away from your present position? 
Does your squelch setting help at all?