Low Band shuts off Jeep Help

[flipped73]

Thanks for all the replies. The radio is wired directly to the battery. The antenna is a Motorola NMO mount the mast was trimmed by the tech. It is mounted to a homemade mount that bolts to the rear passenger side of the Jeep behind the tail light. I will check the alternator Monday when I can get it back into our shop.

J-Fire is short for Juvenile Fire Intervention Program. We educate juvenile firesetters about the dangers and consequences of playing with fire.

Again thanks for all the advice. I'll keep you posted.

 

[Confuzzled]

- it's RF getting into the computer.

Like I said, check with a Jeep dealer. See if they know of any problems with the frequencies you're using.

Has this vehicle got any other options or add-ons like LoJack or OnStar that might include a remote shut-down command?

 

[OCO]

Thanks for all the replies. The radio is wired directly to the battery. The antenna is a Motorola NMO mount the mast was trimmed by the tech. It is mounted to a homemade mount that bolts to the rear passenger side of the Jeep behind the tail light. I will check the alternator Monday when I can get it back into our shop.

J-Fire is short for Juvenile Fire Intervention Program. We educate juvenile firesetters about the dangers and consequences of playing with fire.

Again thanks for all the advice. I'll keep you posted.

Let us know of the results......

 

[majoco]

Did you say what driving condition you were in when you keyed the mike? Idling, cruising or what? The alternator/ battery question will rear it's head depending on what you were doing at the time.

If you had just started the engine from cold and the alternator was still trying to stuff some charge back into the battery at idle when you wanted 30amps to run your radio, then no wonder it stalled

 

[mancow]

Maybe I missed it but what year is it?

I have a 2010 JKU running a 110 watt X9000 lowband with NMO 10 meter on the 3rd brake light, FT857 with Z11 Pro2 tuner on a Chameleon V1 on the plastic license plate holder and a Comet dual band Vhf/Uhf on the passenger side brake light aftermarket protection frame. I have zero RFI issues. The X9000 is in the back cargo area with the cable routed through the tail gate wiring harness.

 

[OCO]

Anyone know what the radio actually draws on xmit? I was swagging 30 amps...

 

[mancow]

It's close to that I think.

 

[rfradioconsult]

Ensure the metal case of the transceiver is directly grounded to the vehicles body, don't rely on the negative lead to the battery to provide a RF ground to the radio case.

 

[k5phw]

I don't know what year your Jeep is, but DO NOT pull a battery lead while it is running.
That can kill the PCM.

 

[flipped73]

Did you say what driving condition you were in when you keyed the mike? Idling, cruising or what? The alternator/ battery question will rear it's head depending on what you were doing at the time.

If you had just started the engine from cold and the alternator was still trying to stuff some charge back into the battery at idle when you wanted 30amps to run your radio, then no wonder it stalled

It does it at all stages of driving from idling to driving down the road at 55. No added accessories. It is fused with a 30 amp inline fuse. Radio mount is screwed directly to the transmission hump. (the only place big enough for a radio that big) It's a 1997 TJ. If it wasn't still -1 degrees today at 10:45 I'd go put the multi-meter on the battery. I think I will also run a fresh ground from the battery to the body and ground just to be sure that's good.Any suggestion on wire size for the ground?
Thanks
Chris

 

[mm]

I have that same model radio on 6 meters, and the radio only draws 20 to 21 amps maximum at 110 watts output into a 1/4 wave whip, the midland PA's are a ~ 50% efficient design.

This sure sounds more like stray RF getting into your electrical system, do have other low band frequencies that do not cause the problem or are you only licensed for one frequency ?

Also you probably have aftermarket lights/strobes installed, are they properly grounded and filtered ?

Everything that is an aftermarket installation is a source for stray RF getting into the system.

A problem that I had was still poor shielding of manufacturer installed wiring and devices, even with properly bonded antennas which were the standard ball mount low band models, and bonded grounded radio, I still needed to place a toroid/current choke at the antenna end of the coax and at the radio end along with a heavy duty filter in the supply leads to the battery.


Mike

 

[Squad10]

If it applies to your vehicle, may want to consider low band transmit RFI to the OEM Sentry Key feature. I believe I've read there is a way to disable Sentry Key.

SENTRY KEY
The Sentry Key Immobilizer System prevents unauthorized
vehicle operation by disabling the engine. The
system does not need to be armed or activated. Operation
is automatic, regardless of whether the vehicle is locked
or unlocked.
The system uses ignition keys that have an embedded
electronic chip (transponder) to prevent unauthorized
vehicle operation. Therefore, only keys that are programmed
to the vehicle can be used to start and operate
the vehicle. The system will shut the engine off in two
seconds if someone uses an invalid key to try to start the
engine.

 

[Quickcall]

I see you are just down the road from me. If all else fails head over to Tri-County Communications in Oneonta. They are fantastic at solving issuses like that, and all around good guys. Creative Electronics over in Laurens is also a good alternative.

 

[flipped73]

I see you are just down the road from me. If all else fails head over to Tri-County Communications in Oneonta. They are fantastic at solving issuses like that, and all around good guys. Creative Electronics over in Laurens is also a good alternative.

I have thought of both those options. I'm just trying to do this on the cheap due to money being short. But thanks for the suggestion. Our Village uses Tri-County for all our radios. They are great guys. As is Dean over in Laurens.
Thanks

 

[zz0468]

...This sure sounds more like stray RF getting into your electrical system...

Yes, and it's super easy to test for. Just key the radio into a dummy load. If the problem persists, it could be DC power related. If not, it's radiated RF.

One simple test can steer where he should look.

 

[rescue161]

Yes, and it's super easy to test for. Just key the radio into a dummy load. If the problem persists, it could be DC power related. If not, it's radiated RF.

One simple test can steer where he should look.

100% agreed!

 

[krokus]

Check your local auto parts store. They should have replacement ground leads. Take the old one in with you.

Honestly, unless you see some degradation of the conductor, just cleaning the contacts might be sufficient.

What sort of connection do you have for the ground of you radio? How clean are the connections? While running the radio's ground to a point on your chassis will work, connecting it to the battery is better. (For you leads between the battery and the radio, I would suggest an 8 AWG, as a minimum.)

 

[AK4GA]

Check the coax connector.

I had all kinds of problems in my patrol car. When I keyed the 50 watt radio mounted in the console all kinds of stuff would malfunction or shut off.

I found the coax was just shoved into the reducer on the PL259 plug on the back of the radio. I cut it off and reinstalled it properly. As in soldering the center conductor and the shield to the body of the connector. This isn't how the installer did it evidently.

Not a problem since. I would begin there, then make sure the antenna mount is grounded properly.

 

[kb4mdz]

Interesting; make sure that this homemade mount is very well grounded to the rest of the metal of the vehicle.

And you might consider getting some ferrite beads to snap onto the wires going to those lights; you might be picking up RF from the antenna, and sending it straight back into the electrical system to places that don't like it.

Thanks for all the replies. The radio is wired directly to the battery. The antenna is a Motorola NMO mount the mast was trimmed by the tech. It is mounted to a homemade mount that bolts to the rear passenger side of the Jeep behind the tail light. I will check the alternator Monday when I can get it back into our shop.

J-Fire is short for Juvenile Fire Intervention Program. We educate juvenile firesetters about the dangers and consequences of playing with fire.

Again thanks for all the advice. I'll keep you posted.

 

[flipped73]

Added extra gounds to the body and the frame from the battery. Didn't help. Grounded the radio body. Didn't help. Checked battery voltage with key and radio off. I got 13 volts. Started the Jeep and I get 14.7 volts. Turned on everything in the Jeep and get 14.3 volts.

The antenna mount is grounded through all 3 bolts in the tail light. I also grounded the antenna. The part that contacts the mount. Also tried a magnet mount atenna from a friend. It did the same thing.

I don't have a dummy load to try. Are there any other suggestions before I have to take it to a shop?
Thanks for all your suggestions I really appreciate it. I will let you know what I find out.
Chris