EMI Shielding for RADAR cable

[Fever]

Hi all-

Garmin recommends EMI shielding if I run my RADAR cable near GPS, FF, etc cables. This will be the case, as I'll be running the RADAR network and power cables down the hardtop tube to the electronics box on the dashboard.

My guess is several people have done exactly the same thing.

I have to wonder if power and GPS/RADAR cables all crammed into one tube makes any difference.

Has anyone had to deal with this?

And if EMI shielding is really a must-do, how then do I do it? Internet searches aren't too helpful. Maybe wrap EMI shielding tape around the cable.

Thanks,

Mike

 

[SmokyMtnGrady]

Hi Mike,
I have a Garmin 24XHD radome. I did not shield my radar cables and I have not noticed any RFI or if it is there, I have tuned it out with the gain control. I don't think it would hurt to have it but in my case it has not hurt to run it without the shielding. When you run energy through a wire you can also get magnetic fields also along the wire. Again, I have not noticed any interference.

 

[Fishtales]

Maybe check out a magnetic choke, they snap on over the wire. Sometimes you can add these to the end(s) of the cable.

 

[freddy063]

Most radar cables have foil around each pairs in the cable it self, and a outer shielding over all pairs. I f it a cable from the vented it should be good.

 

[SkunkBoat]

These new radars have all the transmit stuff up in the radome. Its only sending digital data to the Multi-function display. Its not going to interfere with anything.
That cable is usually shielded. If your VHF antenna cable is not properly connected, it would be the only likely source of interference.
Like the others have said, I would go with what you have first. Most likely you will have no problem.

That statement by Garmin is the catch-all phrase that all electronics comes with because they don't know what kind of crazy setup you might have rigged that might actually cause problems. Kind of like the "turn all cell phones off while pumping gas and riding in airplanes"

 

[Fishtales]

I agree with Freddy... If you are using factory cables you will be fine. I have read in the past that they recommend you do not adjust the length or cut in anyway. While RF is only transmitted in the dome, there are digital and power lines in the cable which if not properly shielded could create problems. The factory cables should be designed for this.

 

[Fever]

Thanks everyone for the responses.

Garmin says it's okay to cut the network cable. They provide a replacement terminal and instructions. Should be okay. Besides being 45 feet long and only 9 ft from the radome to the display, the terminal is too big to pass through the raceways. I need to cut off the end to snake it through the hard top.

The power cable is also 45 ft long, but it has to all the way back to the battery. By the time it gets back there, I can coil and stow the excess.

Thanks,

Mike

 

[SkunkBoat]

The power cable is also 45 ft long, but it has to all the way back to the battery. By the time it gets back there, I can coil and stow the excess.

Why go all the way to the battery?
You don't have a fuse panel in your hardtop or dash?

 

[Fever]

The power cable is also 45 ft long, but it has to all the way back to the battery. By the time it gets back there, I can coil and stow the excess.

Why go all the way to the battery?
You don't have a fuse panel in your hardtop or dash?

OH! I assumed by the age of the boat and the jumble of wires in the hard top radio box that it was an after-market thing, so I did not trust it. (Have had too many surprises on other boats...so...)

Already checked the fuses there. They are 10a and the radar is 7.5 fused. Think there's four slots. Already have three used by stereo, VHF and second GPS/FF monitor.

If i want to be sure, i just need to check the size of the power cable it's connected to.

Thanks for bringing that to my attention.

 

[SkunkBoat]

Pretty sure Grady fed the all the hardtops with 10AWG wire to a panel.

If the panel is old, you might want to change it now. They get brittle after 10 or 15 years. You go to pull a connector off and it cracks in half. Just happened on my 2000 265express.
It happened on my old boat too.

 

[Fever]

Hi All-

I just wanted to note that when I started cutting cable for the installation, I noticed both the network and the power cable are shielded internally.

Seems like Garmin has a "catch all" phrase for every situation in their instructions. covering their bases, so to speak.

Thanks,

Mike

 

[Fever]

Pretty sure Grady fed the all the hardtops with 10AWG wire to a panel.

If the panel is old, you might want to change it now. They get brittle after 10 or 15 years. You go to pull a connector off and it cracks in half. Just happened on my 2000 265express.
It happened on my old boat too.

Doing just that.

Also saw a second pair of 10ga wire stubbed out in the radio box. Has power. But, I decided to just get a longer fuse box and put everything on the first circuit. If there are issues with radar performance, I may hard wire with in-line fuse to the second power source.

Thanks,

Mike

 

[Fever]

Update:

I installed without any additional shielding other than what was inside the cables. Also, decided to cut the power and network cables shorter and use the terminations that garmin supplies with the radar. Cables come 45 ft long and it's only 3 ft to the radio box and 10 ft to the GPS unit.

Finally got it out and used it this weekend, and I can say I am 100% satisfied with the results.



Mike