Radio interferance problems (1 Viewer)

[green fj]

I have Just rebuilt an Fj45 1972 Iv completely rewired everything. Now the radio which is brand new work perfectly when the Ute is idling and not running but after running at higher revs for about 10-15 min the quality completely breaks down till the radio cant be heard at all. This issue is the same what ever the media, usb, blue tooth or radio.

 

[1911]

Does it buzz, and the buzzing increase with engine rpm? If so, it's either the alternator or the ignition being picked up by the radio antenna. If that is the case, you can put capacitors on the coil and the alternator, and you can add some more ground straps in strategic places, such as between the exhaust pipe and the frame.

 

[green fj]

Hey thanks no it doesn't buzz the sound just completely breaks down until it is no longer recognizable as music. I have an all in one Dizzy no external coil. Iv bee playing with electrics a bit for a while but this is an issue iv never encountered before.

 

[green fj]

When I rewired the Ute I started from scratch. Theres more earth wire then you can count every where. (wires cheap) Wind screen frame Radio Wippers UHF all earthed. Plus direct negative to all electronics as well as the earth wire

 

[emac]

After the radio starts to crap out does turning off the engine fix the issue?

 

[Tin basher]

Looks like a clean instal
I try to keep radio speaker wires and radio it self away from power wires as much as possible
It appears you have main power Gage's right between your stereo and cb
And then a bank of switches on other side of radio
May not be a problem If possible can you disconnect power wires running up to there and try driving it with just the stereo operational to see if you get same kind of feedback

 

[lenmn]

Or power the radio from an external supply. Based on sufficient grounding it may not be conductive interference but rather radiated or coupled interference. Shielded power and ground wires will reduce coupling from radiated emissions.

 

[green fj]

yes As soon as I drop the revs even just throw her in neutral and coast the radio revives its self and once you've been driving for a while revving it has a direct affect on the volume. The only real power going up to the console is for the radio, uhf, wipers and engine watch dog. the gauges are just readings off the power already there. I can pull a few fuses for the wipers and other extras but the issues doesn't change if Iv got the wipers on or head lights or any extra electrical. When parked I can have any electrics I want and no interference but the problem only becomes present after a while of high speed driving.

 

[green fj]

For an alternator Iv installed a 60amp alt with an external bosch regulator. Running to the Starter motor then to the start battery whilst also charging a second battery through a red arc isolator. most of my electronics are feed from the second battery to try and eliminate any flat battery issues. The power is now located in th e glove box and has two feed one from each battery, first two fuse banks are the main battery which are the main features like lights, wipers, gauges and dash controls. the second half are the extras, radio, uhf, auxiliary lights, fridge points and 12v points.

 

[green fj]

Or power the radio from an external supply. Based on sufficient grounding it may not be conductive interference but rather radiated or coupled interference. Shielded power and ground wires will reduce coupling from radiated emissions.

I could almost guarantee that will fix the issue but the problem is how to make the radio work with out carrying a battery on the front seat. or only being able to listen when parked. I suspect the Dizzy is the issue. It s is one of the DUI from cruiser corps. terrific spark and power but unsure how to fit a condenser. as the original points had on inside the dizzy.

 

[lenmn]

I could almost guarantee that will fix the issue but the problem is how to make the radio work with out carrying a battery on the front seat. or only being able to listen when parked. I suspect the Dizzy is the issue. It s is one of the DUI from cruiser corps. terrific spark and power but unsure how to fit a condenser. as the original points had on inside the dizzy.

Lol. Suggested the external supply as a test and process of elimination. Not familiar with the DUI dizzy. Maybe it's the Bosch regulator and the batteries are fully charged and you could disconnect it and take a brief test run? Also it might be possible to add a condenser external to the dizzy as on some stock setups.

 

[green fj]

Lol. Suggested the external supply as a test and process of elimination. Not familiar with the DUI dizzy. Maybe it's the Bosch regulator and the batteries are fully charged and you could disconnect it and take a brief test run? Also it might be possible to add a condenser external to the dizzy as on some stock setups.

Ill have a play and post results it could take a couple of days thanks for the ideas.

 

[lenmn]

My suggestions are not based on direct experience and there are many others on MUD that have more related knowledge and experience. Good luck!

 

[bikersmurf]

I'd suggest running a jumper to ground to the battery and see if that'll change anything. there are also power filters that can be installed to clean up the incoming power if running from an external power source helps. Also running extra grounds, even if only temporary to remove the possibility of floating grounds.

I also hope that's wire wrap not just "Electrical" tape... Electrical tape will turn into a sticky mess after it warms up a bit.

 

[Tin basher]

The dui dist uses gm hei type electronics
I believe the cap coil ignition module all interchange with gm inline six parts
At least the dui dist we have for a 302 Ford uses gm parts
I don't think it could be that I have a Chevy v8 in mine and dist is inches away from radio
And it has Bluetooth usb etc and rca cables going to a amplifier

 

[Coolerman]

Beautiful wiring and truck!

It is easy to add filter caps/isolation traps to your truck to see if that is the issue. Do a Google search on Automotive Noise Filter and read away.

From what you are describing, I would not rule out the possibility of a defective radio or power amp. Most noise that interferes with a receiver or amp, comes in through the power wires, speaker wires, or antenna. What you describe happening, seems to be a breakdown in the audio path somewhere, not noise coming in from outside. If you could substitute another receiver, or use your phone, or mp3 player straight to the amp, that might isolate the issues to the receiver. Also maybe hookup speakers straight to the receiver, bypassing the amp, to see if that isolates the issue to the amp.

 

[1911]

Hey thanks no it doesn't buzz the sound just completely breaks down until it is no longer recognizable as music.

OK then, this sounds almost like an impedance mismatch between the amp and the speakers to me (had something similar happen to me on a motorcycle stereo). Are you sure that the speakers have the same impedance as the amp can satisfy? Most car amps are designed to drive 4 ohm impedance speakers, but if you wire multiple speakers in parallel, the impedance of the system will drop and the amp doesn't have enough power to drive them, resulting in the muddy, unrecognizable noise you describe. How many speakers do have wired into a single channel? If you're running front and back speakers, you really need a 4-channel amp.

 

[Coolerman]

But if the impedance is mismatched wouldn't it sound muddy all the time, not after a period of time?

 

[green fj]

I'd suggest running a jumper to ground to the battery and see if that'll change anything. there are also power filters that can be installed to clean up the incoming power if running from an external power source helps. Also running extra grounds, even if only temporary to remove the possibility of floating grounds.

I also hope that's wire wrap not just "Electrical" tape... Electrical tape will turn into a sticky mess after it warms up a bit.

Hey thanks the tape is harness tape seems really good to work with too. As I described earlier I've got got grounds every where and direct neg as well. Ill check out the power filters haven't had a chance to run it from an external power supply yet.

 

[green fj]

OK then, this sounds almost like an impedance mismatch between the amp and the speakers to me (had something similar happen to me on a motorcycle stereo). Are you sure that the speakers have the same impedance as the amp can satisfy? Most car amps are designed to drive 4 ohm impedance speakers, but if you wire multiple speakers in parallel, the impedance of the system will drop and the amp doesn't have enough power to drive them, resulting in the muddy, unrecognizable noise you describe. How many speakers do have wired into a single channel? If you're running front and back speakers, you really need a 4-channel amp.

Hey I don't have an amp just the head unit through a high low pass straight to two 6 inch speakers rear and 1 1/4 tweeters front. Shoundnt have much trouble driving that, not even trying to go too loud.