VHF static coming from networking cables

[Defiance Sportfishing]

I'm getting static on several VHF and 2 Meter frequencies. I've traced the source of the noise to my DSM 300 and Radar (28" Digital Dome) raynet cables. Remove cables from high speed switch or back of device (E125 & C95) and static goes away. I upgraded switch to HS5 and replaced all RayNet cables, static still exists. I've put ferrites on both ends of all cables and static still exits. What else would you recommend testing ?

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Defiance Sportfishing,

How much distance is separating:
- the radios from the network switch
- the radios from the DSM300
- the radio antenna cables from the network cables (specify minimum distance)

How many RF chokes have been applied to the network cables?

[Defiance Sportfishing]

Hi Chuck - My answers are inline.

How much distance is separating:
- the radios from the network switch - 6" - 12" but tested with networks switch a couple feet away and still had static

- the radios from the DSM300 - several feet

- the radio antenna cables from the network cables (specify minimum distance) - They are very close (2") in one spot then seperate to 6" - 12".

How many RF chokes have been applied to the network cables? I currently have 2 on each ends of the DSM and Radar cables

[Chuck - Raymarine - Moderator]

Defiance Sportfishing,

This is the first RF noise issue which I can recall that was associated with a system's Ethernet cables. Should the noise not be able to be squelched with via the controls of the communications equipment, then the following is recommended:
- verify that that the RF drain leads /terminals of the marine electronics equipment have been connected to the vessel's bonding system
- check the grounds of the communications equipment
- start by adding up to six snap-on ferrite beads to the communications cables which are suspected of causing the noise.
- provide greater separation of the communications equipment from the marine electronics. Raymarine recommends that communications equipment not be installed within 3' of the marine electronics.
- provide greater separation of the antenna cables for the communications equipment from the marine electronics. Care should be taken to not chase/bundle communications cables with other cables. Separation of 2-3' would be wise.

[SteveME]

I'm in the end stages of upgrading my MFD and VHF radio. The plan was to mount them in the same positions as the previous (approx. 16" separation). Previously, the antenna cable came in from the opposite side of the helm and was run across the dash to the radio. Ugly but separated from other electronics. I'd like to clean things up which would mean re-routing the antenna cable up in the vicinity of the MFD. Question is, can the cable be shielded to avoid potential interference?

[Chuck - Raymarine - Moderator]

Steve,

As had been suggested earlier within this thread, should RF energy from the MFD cause noise within the VHF radio or cause it to break squelch, then it would be recommended that RF chokes be applied to the MFD's power cable.