VHF radio disabled/static turning on Garmin Plotter 188c

[moccq]

Greetings,

Scenario Garmin 188cc/236 Chart Plotter with an ICOM VHF radio..

The VHF radio becomes static when I turn on the Garmin plotter..and is only usable when the Garmin turned off.

Some sort of interference is going on, but not sure where to start, any ideas or thoughts would be appreciated.

 

[seasick]

Diagnostics depends somewhat on history. Did the setup ever work correctly?
If so, first thing to check are ground wires and connections. Also check the VHF antenna connection.

 

[Parthery]

I chased a similar gremlin for 6 months before I got it.

Couple things to look at...make sure your antenna cable and your transducer cable are coiled separately. Also, make sure your transducer cable is not touching anything metal in the boat. That was where my noise was coming from; it was tie wrapped to a support bracket for the inside of the electronics box.

Finally, antenna quality can play a factor. Better antennas are shielded better, and RG-8X cable is shielded better than RG-58.

 

[BobP]

Make sure VHF antenna connector is proper and tightened to the radio. When you do a radio check from the radio, is it answered?

 

[enfish]

I've dealt with a similar issue, though from your description my problem didn't seem as severe. Garmin fishfinders are not well shielded and put out electrical noise. I was getting static on my fixed VHF during every transducer pulse from my Garmin 240 Blue. It didn't make the VHF unusable, just weaker VHF receptions were overpowered by pulsing static. My troubleshooting involved using a handheld VHF which proved the interference was coming through the air and not through the wiring. The interference got worse and worse the closer I got to the Garmin unit, so it did not involve any wiring or cables. It was actually coming directly from the Garmin. It went away completely when I covered the Garmin unit with aluminum foil. That solution is a bit kludgey, so most of the time I just live with the interference.

Other than that, the other posters all have offered solid advice.

 

[moccq]

Acking to all of the replies, Thank you so much, I'll drop a post here over the next several days as I start the troubleshooting process...we'll see how it goes. Appreciate the feedback.

 

[moccq]

8/7 update:

The 188c GPS mounted in the lower helm box wiring runs up the hardtop pipe into the hardtop box and it connected to the power panel along with a two wire connection to the ICOM M302 VHF Radio for DSC comm ( I believe)..

Noted the VHF Shakespear Antenna cable slack was tucked down into the hardtop pipe , meaning it was sitting alongside the GPS cable.

All of the wiring was cabletied together..

I pulled all the ties apart, separated the cabling and pulled the VHF Antenna out of the pipe and coiled it away from the GPC Cable ( although it is only now 3-4" away and still in the hardtop box area.

Still doing some testing with these changes and will have to repost again..still some static..but now I seem to be receiving some channels on the VHF.

Quest: Wondering if I should somehow shield the wires for the GPS cable that connect to the power source and VHF Radio(serial connects)..or does it matter..

Thoughts ?

 

[Slacktime]

moccq, I had the same problem with the Garmin 188C on my 2000 Adventure 208. I tried everything including filter capacitors on the dc, bi-filar wound chokes separation of circuits etc. One day out of desparation, I moved my hand held radio running on it's own batteries near the unit and discovered that the interference was radiated from the unit. No amount of filtering would stop that. The best I could do was to cover the Garmin in doubled aluminum foil and make sure it was grounded to the GPS antenna connection. That helped to reduce the noise, but it didn't go away completely and I just lived with it. The final solution came when I sold the boat, bid farewell to the Garmin and bought a 2003 300 Marlin which has a Lowrance unit. No more troubles with interference!

regards, Slacktime

 

[simmonsviolet]

Hello..
I think, you have to check all the connections and wires. I also did the same thing. Thanks..
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Have a look at: plastic netting | releasable cable ties