GMRS antenna/reception question/help?

[diesellord]

Greetings- hoping some radio experts out there might have some suggestions with the setup I’ve put together for radio comms. It’s at least tangentially related to the GX itself and to the GXOR set ups…

Issue 1: I can “hear” a higher pitch noise through the radio speaker that matches the RPMs of the engine (higher pitch with higher rpm and vice Versa). Also, tbd on the reception strength.

Issue 2: if the big ditch lights go on, radio reception goes back to static. Direct correlation.

Set up:
-Midland MXT-275 with the ghost antenna
-mounted to the passenger side ditch light bracket with extension.
-The antenna coax is routed across the the engine bay, behind the ‘shroud’ closest to the windshield/firewall…then pokes through the rubber gasket near the steering wheel.
-Inside the cab, the coax is routed behind the dash and into the glove box cubby where the radio head unit sits.
-I would say this is the pretty typical set up.

Attempted Solutions:
-cut the coax cable down so none of it is coiled. No excess. No noticeable effect
-added ferrite cores at various points in the system. No noticeable effect.
-attempted to add a ground wire from the antenna base on the ditch light mount to a proper ground inside the engine bay. This was admittedly a sloppy (with terminals and wires I have lying around) attempt but this made things worse anyway.
-move the antenna and extension bracket to the outside of the ditch light.

So that’s where I’m at! The radio is ‘fine,’ if not annoying. Reception is, I guess, fine. I have virtually the same set up in my van with a lower gain antenna and it’s clear as a bell with zero feedback. GX has better parts, and worse quality, reception, and interference.

Any suggestions out there? Better threads with more info?

Thanks!

 

[Rednexus]

I have the exact same radio with the antenna mounted in the exact same place (including feet of coiled up wire in the engine bay) and have no interference issues from my lights or engine. I think the only difference in our setup is that I routed my antenna wire through the PS firewall grommet, instead of running it over to the DS grommet. This required pulling the ECU out to reach the grommet, but worked out well as I have the radio in the DVD player cubby.

Given than you seem to be receiving interference from multiple sources, I'm thinking you have an connection issue somewhere. It may be where the cord screws into the bottom of the antenna, or in the piece of the cord where the shielding is damaged. The screw-in connection to the base of the antenna is kind of weird and easy to mess up - so that is where I would start.

I'd suggest reaching out to Midland and seeing if they can help troubleshoot.

 

[Jstawgn]

How did you power it? Most radio need to be connected directly to the battery. I tried to use my Auxbeam power switch and it interfere a lot and doing weird things. I end up adding a separate relay and it have been fine after that.

 

[diesellord]

Time to triple check connections and talk to midlands- thanks @Rednexus

@Jstawgn - let’s talk power. I grabbed power from the under dash fuses with a fuse tap into the passenger side power seats fuse (always on). So it’s not “directly” tapped into the battery (just extra steps), nor is it connected to the 12V cigarette lighter by the shifters.

Maybe that somehow makes a difference? But the ferrite cores should help?

 

[diesellord]

Alright, one other cord/cable worth mentioning- there is the handset cable and extension (basically an Ethernet rj45 cable) running from the radio unit in the glovebox dvd cubby, that sneaks behind the radio and pops out on the drivers side console plastic (near the gas pedal). From there, the handset plugs in and is mounted under the vent. (I have pictures somewhere).

Possible to get this interference through the Ethernet cable? That doesn’t really explain the interference from turning the ditch lights on/off.

 

[Rednexus]

I have my GMRS going thru a dedicated relay/fuse that's connected to the battery.

I don't think the ethernet cable is the issue unless it's nicked or something. I actually have mine extended from the radio to the center console with basic house ethernet cable, then I have a round jack that the handset plugs into. I've never seen ethernet affected by lights/engine stuff. I have had spark plug wires cause radio interference in old Chevy V8s.

 

[Jstawgn]

Radio power need clean power with no interference. Try connecting to battery directly. Both positive and negative. If the problem goes away then you found your problem.

I was stubborn before and power it using Auxbeam switch panel. It was fine for a few months until I need to transmit at high power. All light start flashing every time I hit transmit button. Wire it directly and all problem goes away.

 

[diesellord]

Follow up from awhile ago - finally- in case anyone in the future reads.

I rewired and got power (positive) directly from the battery and a proper ground. Ta da! Did the trick. No interference.

Thanks again!