VHF marine radio RFI

Hello antares36,  Welcome to the Forum.

Am not familiar with the Ferris Charge Controller (CC).

In general,  PWM CCs create fewer RFI problems than do MPPT CCs,  although a number of MPPT CCs DO meet  FCC Class B Radiated and Conducted Emissions standards (for the USA).

Some PWM CCs do have a switch setting that is said to reduce the RF emissions.

There are some relatively standard emission reduction techniques  --  Ferrites on the PV array cables,  placed near the CC,  with a number of turns of the cables through a toroid,  or Snap-On ferrite.   Sometimes,  placing a good quality capacitor across the PV input terminals in the CC wiring compartment (if it has one).

At times  ferrites,  and or a capacitor across the CC's battery terminals,  very close to the CC can help.

As always,  separating the PV array from the location of the antenna can help (yea,  this is often difficult on many boats),  and perhaps a large toroid or snap-on ferrite on the VHF radio's coaxial feed line, to reduce any common-mode currents on the coax shield,  and so on.

At times,  twisting cables together from the PV array to the CC,  and the battery cables from the CC to the battery can help.

At times a portable radio can help "sniff"  RFI.  In this case,  perhaps a battery operated portable that covers the 130 MHz  Aviation band would help.  Move the radio around the cables to try to see where the Emissions are coming from.

You might try switching off the PV input to the CC,  and using the portable radio,  see how the emissions change.  It is possible that some or most of the RFI might be coming from any Microcontroller that may be in the CC.

And so on,  just to start the ball kind of rolling.   Vic