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power supplies with minimal radio interferance?

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  • power supplies with minimal radio interferance?

    My m2atx no longer survives cranking, so I figured I'd get a new power supply and hopefully fix my radio reception problem (I can't get any radio stations with my carputer on). I already have the carputer fully enclosed in an aluminum Mo-Co-So case, but that doesn't block the radio interference.

    Are there any power supplies out there that don't really interfere with the radio?

  • #2
    My m2 doesn't give any interference at all. I kept all power wires separate from signal wires.

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    • #3
      There is always a little interference form a carpc, but it should be
      unnoticeable unless you max out the volume playing a blank sound file
      and even then it should be really low

      I think you have a wiring problem, check all your grounds
      and yea keep power wires on one side of the car and audio
      cables on the other, dont run them together

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      • #4
        Originally posted by will1384 View Post
        There is always a little interference form a carpc, but it should be
        unnoticeable unless you max out the volume playing a blank sound file
        and even then it should be really low

        I think you have a wiring problem, check all your grounds
        and yea keep power wires on one side of the car and audio
        cables on the other, dont run them together
        The problem isn't the audio cables; I'm using the Directed HD radio module and it's unable to lock on any stations when the carputer is on, but a dozen or so when the carputer is off. I believe it's either radio interference or maybe some sort of electrical interference over the +12v line (I don't know if that's possible, I'm just speculating). The HD radio module is mounted in my trunk (the carputer is under my passenger seat)...there is a stereo cable running to the carputer and a 12v line coming from the carputer to power the HD radio module.

        I'm also using an aftermarket antenna that's inside of my car's cabin on the rear deck lid (the factory antenna was pretty ugly). I know I can't expect as good reception with the aftermarket antenna, but the fact that I can lock onto stations with the carputer off tells me there's some sort of interference going on. I supposed I can try grounding the antenna at a different point in case the point it's currently grounded to isn't great.

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        • #5
          What kinda gauge power wiring are you running to the M2?
          Why not build a Faraday cage around the M2, or at least check our cable runs?

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          • #6
            Have you tested your carputer with a regular desktop power supply plugged into 110(AC-DC) to verify the M2-ATX was causing RF reception interference? Friend of mine has the same issue but I haven't had time to help him troubleshoot this issue yet to determine if it's the PS or the PC.
            System always under construction


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            • #7
              That's a good point Durwood...in a car, RF noise can be coming from any number of areas...

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              • #8
                i get EXACTLY the same problem with my M2ATX, what I did was fed the HD radio a separate supply from another car battery, turned the carputer on and the radio reception went cack.

                I then repeated the experiment with a DC power supply feeding the M2ATX, same result

                I finaly repeated the experiment with a standard ATX supply feeding the Carputer - i removed the M2-ATX. THe prbolems went away.

                I have since ordered an Opus PSU as i've been told these have the lowest RF interference - they were originally designed for emergency vehicles.
                The epitome of Function over form and is probably the best Car PC in Europe.
                Visit my Homepage

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                • #9
                  Opus FTW!!!!

                  Yet ANOTHER testimonial as to the ****tiness of the M2/M4...

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                  • #10
                    Originally posted by dyne View Post
                    The problem isn't the audio cables; I'm using the Directed HD radio module and it's unable to lock on any stations when the carputer is on, but a dozen or so when the carputer is off. I believe it's either radio interference or maybe some sort of electrical interference over the +12v line (I don't know if that's possible, I'm just speculating). The HD radio module is mounted in my trunk (the carputer is under my passenger seat)...there is a stereo cable running to the carputer and a 12v line coming from the carputer to power the HD radio module.

                    I'm also using an aftermarket antenna that's inside of my car's cabin on the rear deck lid (the factory antenna was pretty ugly). I know I can't expect as good reception with the aftermarket antenna, but the fact that I can lock onto stations with the carputer off tells me there's some sort of interference going on. I supposed I can try grounding the antenna at a different point in case the point it's currently grounded to isn't great.
                    Sounds a little odd, I could see the antenna being inside the cab
                    could be a problem, should be outside, but I am one to talk I have
                    my Wi-fi antenna in the same place.

                    Every time I have had a problem like that, its been a wiring problem,
                    ether a lose wire, connector, or bad ground, I sometimes end up
                    having to pull/tug on the wires to check for that, just don't pull to
                    hard, but you would try something like that with the system on and its
                    messing up, to see if by pulling or moving the wires the problem
                    changes, I also have had grounds in a car be bad, and have to
                    remove the paint from the metal to get a good ground, might also
                    want to check under the hood, might have corrosion on the
                    battery terminals or wires, -use some Vaseline to help prevent that -
                    or the wires or grounds under the hood may be rusted/ corroded.

                    I suspect its a grounding problem

                    Check this link out might help

                    Ground loop problems and how to get rid of them

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                    • #11
                      First, I'm still not ready to blame the M2-ATX until all troubleshooting has been verified. I have an M2-ATX (don't know what revision level) and the Directed HD radio. I get reception, not quite as good as my stock radio, but it works. Stock radio reception is also unaffected by the PC and/or M2-ATX being on.

                      nrgizer-was the PC in the car when you tried the standard ATX supply? How far away was the standard ATX from the actual car?

                      will-this is a RF interference problem, not related to noise in on the audio signal. I think you are still getting confused about this.

                      Does anyone know what the switching frequency of the PWM power supply in the M2-ATX is?

                      Also, what cars are you guys having problems in? My friend that has this issue tried a standard ATX and still had no reception. I just talked to him about it. He even had issues with his GPS antenna not working in the rear of his vehicle where his PC was located. He had to fix that by moving the GPS up front. This was in a Civic.

                      Also, does this happen with the car running, not running, or both?
                      System always under construction


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                      • #12
                        durwood, I've got a toyota corolla - euro model.

                        The case I use is a Jye Jou Nu528 which came with a power supply. When i use this power supply i have zero reception problems. When I use the m2ATX with any combination of source power it screws up the reception. I'm convinced its the M2.
                        The epitome of Function over form and is probably the best Car PC in Europe.
                        Visit my Homepage

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                        • #13
                          Hmmm,

                          well my friend has tried a different supply and still had reception issues. A desktop PC also causes interference on an Alpine radio when located close to the desktop PC (standard PSU).

                          Found some info I was looking for:
                          http://tarzan.ituner.com/support-cen...root=28&id=116

                          The 3.3V and 5V rails operate at 300Hkz. The 12V rail works at ~500Khz and the -12V rail works at 100Khz.All inductors are shielded (closed magnetics) and the M2-ATX has 2 stage input filter, hopefully it will stay very quiet. Pre-scans conform with FCC/CE in the 0-30Mhz (conducted) and 30-1Ghz (radiated) emmisions.
                          For something to disrupt reception through RF it would have to be in the same freq range. According to this, the M2-ATX should not have a problem with this. In most modern computers, CPU, FSB, RAM ETC can operate at 100MHz (x multiplier) however. Uh oh, this is in our FM band range. This is why I think it somehow has more to do with the PC than with the PSU. I cannot explain why it worked for you to change the PSU and problem goes away, but for someone else it does not.
                          System always under construction


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                          • #14
                            In my case I think it's my touchscreen that causes reception issues on my FM reception. I can't be sure though. Same thing though, FM radio reception is horrid with the PC on, once the PC is off, reception is great. You can sit there and watch the computer go into hibernate and the whole time static is rolling on my HU (in the glove box). Then AS SOON as the PC goes into hibernate, BAM full reception.

                            Very strange issue. I'll have to turn off my LCD separate from the PC and see if that makes a difference. Haven't tried that yet because I pretty much got used to just having the PC off when I'm listening to the radio.
                            CarPC:
                            1.8GHz Northwood, Intel 845 Mobo, 512MB DDR, 1x20GB + 1x160GB, Intel GPU, SB Live 5.1

                            Sound System:
                            Phoenix Gold RSD 65cs 6.5" Drivers, Infinity Tweets, Pioneer 305DVC 12", PPI Sedona 630IX, Alpine MRP-M500

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                            • #15
                              subscribed!

                              i'm having the same battle. i've had this issue since i first got my hd radio unit up and running and have never really figured it out.

                              obviously the thing that i wish i could try is: a new mobo, a new power supply, a new case. seems to me one of those or a combination would end up fixing things..

                              please keep this thread updated with any findings

                              im running an M2-ATX and a Via VB7001 mobo in a Mo-Co-So case.

                              i've tried split beads on the wires leaving the case, aluminum foil, unplugging all accessories, monitor powered down, powering the radio from the PC or from the HU stock connections, serial connection, USB connection, you can practically name it.

                              i'd love to believe that i can just replace the M2 and my worries would be gone

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