Midland MXT575 Vehicle Noise

[WSFU671]

I hooked up my new GMRS radio in my 2020 Sierra a few weeks ago. For the first week it was good, clear audio and communication. A few days ago I hopped on a local repeater net and it was nothing but static during receive (and transmission I found out.) I decided maybe it was my location at home, so I went to drive around. The static got worse, almost like a whirling static that matched the vehicle's speed. Only seemed to clear up when I was stopped or parked. I have the radio wired to the positive on the battery and a ground post on the frame. The antenna is the stock 1/4 wave antenna with mag mount that came with the radio. Any suggestions on clearing this up? I purchased ferrite clips on Amazon to see if that will help. I was wondering if I should maybe hook up the negative to the battery as well or maybe moving the antenna. It seems like it happened after it rained recently... Thank you in advance!

[WRYZ926]

Just now, WRUE951 said:

There is a huge difference connecting a battery charger to a battery and connecting a source that draws power..  The latter will have no effects on the vehicles electrical system or its can buss system regardless where you place its ground..   It's always best to place grounds at the common location with other vehicle grounds.     

No not really. You don't want to mess with the BMS or how the computers control the voltage from the alternator to the battery. And every radio manual from the Baofeng to Motorola all state to never connect the radio's ground wire directly to the battery negative post.

I suggest you do your own research about battery management systems and why it is important to run your ground wires directly to a chassis ground.

PS. The reason you never connect a charger to the battery negative post is it can and will mess up the computer. 

[AdmiralCochrane]

The manufacturer of my vehicle provided extra lugs on both battery terminals specifically for connecting accessory loads.

[WRYZ926]

Leave your radio connected as it is with the ground going to chassis. Otherwise you could interfere with the auto start/stop system and the battery management system if you connect it to the negative battery terminal.

It sounds like you might be getting noise from the alternator. I know I was getting noise from the alternator on my 2023 Ford Escape. I put clamp on ferrite beads on the leads to the radios and I put two more, one on each end, on the cable going between the alternator and battery. That helped clear things up for me.

[WSFU671]

4 hours ago, WRYZ926 said:

Leave your radio connected as it is with the ground going to chassis. Otherwise you could interfere with the auto start/stop system and the battery management system if you connect it to the negative battery terminal.

It sounds like you might be getting noise from the alternator. I know I was getting noise from the alternator on my 2023 Ford Escape. I put clamp on ferrite beads on the leads to the radios and I put two more, one on each end, on the cable going between the alternator and battery. That helped clear things up for me.

I did purchase a kit of the ferrite clamps on Amazon, has a few sizes in it. I will certainly give it a shot. 

[WRYZ926]

Make sure to use good quality electrical tape and tape up the clamp on ferrite beads so they don't fall off.

[WSFU671]

19 hours ago, WRYZ926 said:

Make sure to use good quality electrical tape and tape up the clamp on ferrite beads so they don't fall off.

I put some ferrite clamps on the radio but it didn't seem to help at all. I don't know if I should just use one or a few. I put one on the coax, one on the power wire before the battery and one on both the ground and power wire before the radio itself. It didn't seem to make any difference.

[WRYZ926]

Find the main cable going from your alternator to your battery. Once you find it, put a clamp on ferrite bead on both ends.

And it helps to use a sloughy bigger clamp on ferrite so that you can do at least 3 wraps of the wire through it. I only do that on the power leads going to the radio.

I don't know if putting clamp on ferrite beads on the alternator to battery cable will fix your problems, but it sure won't hurt a thing.

Another thing to check is to make sure the alternator is grounded to the chassis correctly. I know the motor block is grounded, but sometimes putting a ground strap directly from the alternator ground/case to the chassis does help.

[nokones]

It's worth a try!

https://powerwerx.com/dc-line-noise-filter-powerpole-connectors

[WRYZ926]

10 minutes ago, nokones said:

It's worth a try!

https://powerwerx.com/dc-line-noise-filter-powerpole-connectors

I forgot all about inline noise filters. We use to use them with CB's back in the day.

[tcp2525]

Are you using an external speaker? If so, unplug it and see if there's any change. It's just a long shot.

[WRUE951]

Try installing a braided ground strap from your hood to the opposite chassis and even across your exhaust and the chassis.  Use an inline noise filter, Kenwood and Icom make a nifty one and use ferret beads.. Make power connections directly to the battery with quality 10GA wire. both ground and positive.   That should eliminate most all your noise problems.  Ram Trucks are notorious for generating noise in Ham radios... I've applied everything i mentioned to friends with Rams and problems eliminated.   

[WRYZ926]

6 hours ago, WRUE951 said:

Make power connections directly to the battery with quality 10GA wire. both ground and positive.

That is not advisable nor correct with newer vehicles equipped with the battery management system. You can actually cause problems by attaching accessory ground wires and chargers directly to the negative battery terminal. Always use a good chassis ground no matter if you are wiring up a radio or other stuff and also when connecting a battery charger.

Pretty much all newer vehicles made in the last 5-8 years all have the BMS module on the battery negative terminal. This is what controls how much voltage goes from the alternator to the battery. And you can really mess things up if your vehicle is equipped with the auto start/stop system.

And the 2020 GMC Sierra does have the BMS.

[nokones]

7 hours ago, WRUE951 said:

Try installing a braided ground strap from your hood to the opposite chassis and even across your exhaust and the chassis.  Use an inline noise filter, Kenwood and Icom make a nifty one and use ferret beads.. Make power connections directly to the battery with quality 10GA wire. both ground and positive.   That should eliminate most all your noise problems.  Ram Trucks are notorious for generating noise in Ham radios... I've applied everything i mentioned to friends with Rams and problems eliminated.   

Don't run the radio ground/negative lead directly to the battery. Always ground directly to a factory chassis grounding point. The radio manufacturers such as Motorola makes a point in their radio installation instructions where to terminate the radio ground lead and it is not at the battery. You can be rest-assured that their engineers know what they are talking about regarding the proper procedure for grounding the radio and accessories. "Some People" are not Electrical or Automotive Engineers.

[UncleYoda]

I'm not an engineer, never played one on TV.  But connecting both wires from the radio to the battery with a fuse on the red wire has worked well for me.  The only time I had a noise problem was with CB connected to the auxiliary cigarette-lighter type socket (is there a better name for those?).  I have used other radios that way without a problem.  (And this is on a Ram, V6, not much extra electronics just A/C and built-in AM/FM.)

[SteveShannon]

2 minutes ago, UncleYoda said:

I'm not an engineer, never played one on TV.  But connecting both wires from the radio to the battery with a fuse on the red wire has worked well for me.  The only time I had a noise problem was with CB connected to the auxiliary cigarette-lighter type socket (is there a better name for those?).  I have used other radios that way without a problem.  (And this is on a Ram, V6, not much extra electronics just A/C and built-in AM/FM.)

I am an engineer and I watch tv.
What @WRYZ926 says is exactly right. If you connect any device directly to the battery you bypass any protective electronics that monitor and manage the charging system and battery. 30 years ago that would not have meant much but the under hood electronics are much more sophisticated now and much more susceptible to getting out of whack when something bypasses them. 

[WRYZ926]

1 minute ago, WRUE951 said:

There is no proven reason to ground separate to the vehicle chassis vs. the battery ground.  In fact, there are more reasons not to ground to chassis then to the battery ground.  Especially in vehicles built today having various chassis insulators, protective sheet metal coatings and metals with poor conductivity.   If you can provide an reasonably explanation from an engineering standpoint, you might have my ear..   

The main reason for using a chassis ground is because of the battery management system AKA BMS. And if you use a chassis ground in the engine compartment then you don't have to worry about insulators or protective coatings, especially if you use a chassis ground that already has a ground wire attached to it.

And this even goes for using battery chargers and battery maintainers. They too tell you not to connect directly to the battery negative terminal. And the reasons are the same - it can cause problems/interfere with the BMS.

[WRUE951]

1 minute ago, WRYZ926 said:

The main reason for using a chassis ground is because of the battery management system AKA BMS. And if you use a chassis ground in the engine compartment then you don't have to worry about insulators or protective coatings, especially if you use a chassis ground that already has a ground wire attached to it.

And this even goes for using battery chargers and battery maintainers. They too tell you not to connect directly to the battery negative terminal. And the reasons are the same - it can cause problems/interfere with the BMS.

you do what you want,,  But i'll tell you, your reason is 100% incorrect.    Like i say, until you can prove to me from an engineering stand point grounding to a separate location is beneficial over grounding at the battery location your point is mute..    And dont confuse from connecting sources with power vs sources that draw power..   Completely different scenarios!!    

[WRYZ926]

Well read my signature. I am done trying to explain things. You have had three different people with plenty of experience tell you the same exact thing. Have a good day.

[WRUE951]

2 hours ago, WRYZ926 said:

Well read my signature. I am done trying to explain things. You have had three different people with plenty of experience tell you the same exact thing. Have a good day.

you haven't explained anything in regards to the difference in placing ground to battery or chassis.    Nada..       Tu-Tu.       But i bet if you google its you'll find Motorola recommends grounding to chassis  to save on material cost since they offen install the transceiver brick the trunks or backends of vehicles..    

[WRYZ926]

Here is a good explanation on why to use a chassis ground.

Quote

THE BEST PLACE TO GROUND ACCESSORIES

MARCH 2, 2019 

Despite common belief, the battery ground is NOT the best place to ground accessories. The battery ground to body/engine/chassis is certainly required in order to complete the circuit which makes up the vehicles ground path. However, it is not the best place to install your ground wire for various accessories.

The issue here is related to ground path, and everything else in the vehicle that ultimately uses the same ground path, which all makes its way back to the (-) side of the battery.

For simple-circuit accessories (lights, relays, electric motors), battery ground is perfectly fine, though anything with a processor or that has high sensitivity to electrical noise or ground path should never use battery ground. The reason here is due to the battery being the return ground path for everything electrical in the vehicle. There can be much electrical noise, or simply high current flow at the battery, which can wreak havoc on your hi-tech or sensitive device/accessory.

The best place to ground electronics like these is actually to the engine itself. Due to the nature of the engine’s construction, there is going to be very little current flow through nearly any ground point you choose on the engine. We recommend the engine block, cylinder head, intake manifold (if aluminum or cast iron), or transmission to engine bolt. Any of these locations will provide you with a great grounding location for your accessories. You do, however, want to keep any related wiring as far away from the ignition system or plug wires as you reasonably can to avoid creating a new issue with ignition noise.

You can also consider this. The OEM manufacturers ground very little directly to the battery. They engineer and create ground locations throughout the vehicle to work for what the vehicle comes originally equipped with and they are not all in the same place. They are spread out. Not just for cost savings purposes, but also for the purpose of not having everything funneling into the same ground path at one point, which can cause problems.

For the purpose of installing gauges that use senders which monitor various engine vitals such as temperature, pressure, and EGT, another good reason for engine ground is to ensure that you have a completed, non-interrupted ground loop shared between the sender and the gauge for the most accurate readings.

https://www.autometer.com/blog/the-best-place-to-ground-accessories/?srsltid=AfmBOopjS7br8Iaan-eUs32NxG9VbdQ7RRJYDiK2gBP3M-DaHN-Z59tD

And some more reading for those interested.

https://electronics.stackexchange.com/questions/329559/when-do-i-connect-to-negative-terminal-or-ground

[tcp2525]

7 hours ago, WRYZ926 said:

Here is a good explanation on why to use a chassis ground.

https://www.autometer.com/blog/the-best-place-to-ground-accessories/?srsltid=AfmBOopjS7br8Iaan-eUs32NxG9VbdQ7RRJYDiK2gBP3M-DaHN-Z59tD

And some more reading for those interested.

https://electronics.stackexchange.com/questions/329559/when-do-i-connect-to-negative-terminal-or-ground

I can't believe that you guys aren't debating "ground loops" How did we forget that?

[WRUE951]

1 hour ago, nokones said:

Don't run the radio ground/negative lead directly to the battery. Always ground directly to a factory chassis grounding point. The radio manufacturers such as Motorola makes a point in their radio installation instructions where to terminate the radio ground lead and it is not at the battery. You can be rest-assured that their engineers know what they are talking about regarding the proper procedure for grounding the radio and accessories. "Some People" are not Electrical or Automotive Engineers.

There is no proven reason to ground separate to the vehicle chassis vs. the battery ground.  In fact, there are more reasons not to ground to chassis then to the battery ground.  Especially in vehicles built today having various chassis insulators, protective sheet metal coatings and metals with poor conductivity.   If you can provide an reasonably explanation from an engineering standpoint, you might have my ear..   

[WRUE951]

4 hours ago, WRYZ926 said:

That is not advisable nor correct with newer vehicles equipped with the battery management system. You can actually cause problems by attaching accessory ground wires and chargers directly to the negative battery terminal. Always use a good chassis ground no matter if you are wiring up a radio or other stuff and also when connecting a battery charger.

Pretty much all newer vehicles made in the last 5-8 years all have the BMS module on the battery negative terminal. This is what controls how much voltage goes from the alternator to the battery. And you can really mess things up if your vehicle is equipped with the auto start/stop system.

And the 2020 GMC Sierra does have the BMS.

There is a huge difference connecting a battery charger to a battery and connecting a source that draws power..  The latter will have no effects on the vehicles electrical system or its can buss system regardless where you place its ground..   It's always best to place grounds at the common location with other vehicle grounds.     

[tcp2525]

43 minutes ago, WRYZ926 said:

The main reason for using a chassis ground is because of the battery management system AKA BMS. And if you use a chassis ground in the engine compartment then you don't have to worry about insulators or protective coatings, especially if you use a chassis ground that already has a ground wire attached to it.

And this even goes for using battery chargers and battery maintainers. They too tell you not to connect directly to the battery negative terminal. And the reasons are the same - it can cause problems/interfere with the BMS.

 Come on guys, you know it's been proven both scientificly and from an engineering perspective that dealing with OEM NITs and aftermarket NITs 0.00001 ohm difference can mean the difference between life and death when it comes to the fine art of picking NITs. Just hook the ground up to whatever place gives you that warm and fuzzy feeling. Now I am going to use my time constructively and split a beer atom.