A simple test of the VHF is to transmit without the headsets turned on; if you have a dirty transmission then the problem is probably with the existing system and that can be any of a number of issues that existed prior to your new EQ1 system.  Look for bad connections, loose wiring, faulty aerial and or coax, wrong aerial, bad power supply, bad earth issues or multiple earthing points. You may wish to install an EQ1 pi filter to ‘clean up’ the dirty power supply.
You may need to adjust the 'gain' in the EQ1 base unit for the radio that you are using. This is done by going into the menu in a 'pilot' headset, scrolling through until you reach VHF communications level and increasing the output. then scroll to 'program controler' and the headset will program the base unit for you. As standard it is set to 23, adjust in steps of 6 until a suitable output volume is reported back to you. Any questions on this one please feel free to call me  0419942645  int +61419942645