So, now that my CarPC is up and running, and mostly done, I have found that my radio reception is terrible when the CarPC is on.

I've tried a couple of things so far to solve the problem:

1. Disabled my wireless card, since it is a high powered (400mW; typical wireless is 15-20 mW) wireless card on a 3 dbi gain antenna. No change in reception whatsoever.

2. Wrapped my carPC in some mesh (located here 20 gauge steel mesh, I figured since the holes in the mesh are much smaller than the wavelength of any possible RFI, it would make a good Faraday cage, and contain the RFI. It looks cool, and the plexiglass case now has more rigidity with the mesh added, but no change in reception.


Some things I may try:

1. new radio antenna, located in different spot in car; where are the radio antennas in a G?

2. Case for my SoundBlaster USB, made of mesh, so if that is making the RFI.

Not sure what other solutions there might be; anyone have any ideas?

Dave

 

1. The antenna is located in the rear window. It's integrated into the glass along with the defroster.

2. Not sure about this.

RFI/EFI is most likely coming from the motherboard. The crystal oscillator used as a frequency multiplier is the most likely culprit. But that might just be a component of the total inteference.

You could try putting foil over your entire trunk mat and see if that prevents any leakage.

I'm putting the finishing touches to my install. Hopefully I'll finish within the next couple days. I'll let you know if the foil or anything else works for me.

 

Yeah I'm dreading booting up my PC and discovering all the problems that never occured on my bench, EMI/RFI being one of them. sigh Feels like it's a never ending project huh?

 

RF hash from the computer shouldn't reduce your reception unless it is SO bad that it is desensitizing the front end of the receiver. Most computer has is from the power supply. The noise manifests itself as "birdies" in the radio. In this type, you are converting 13.8 vdc into a higher voltage dc. Most PS that do this use a high frequency generator that makes a lot of noise. Check that first.

Big audio amps are the same way. I had one in my car that played he11 on my Ham Radio at 50-54 Mhz.

 

Where is your ground located?

 

No, it's not chirps, it's really bad static on my radio. I think it might be the USB GPS antenna that is on the back shelf. Next weekend, some troubleshooting is going to happen.

Dave

 

Ground is located on the metal bar (part of the frame) that is immediately behind the rear seats. It's not a grounding problem, since I have the same ground for my amps, and everything was fine until my CarPC is on.

Dave

 

The only way I got rid of the RF problem was to completely case the computer in metal (aluminum in my case) and house the computer next to the stock amp

 

I also had a custom case and had very bad RFI/EMI - poor radio reception I didn't care much about, but having lines all over the LCD screen was unacceptable. I tried noise filters on the power line, which did help a little but dropped the voltage going to the PC (which my OPUS 150 did not like too much).

I finally bought an aluminum Travla C138 and stuck it in the passenger side rear corner (under the carpet, where the tools used to reside) and all is well. No lines - no crackles or buzzing - no static.

You can test this by taking the PC out of the car and playing audio etc while connected to AC power. Actually even with the PC left in the car, when I powered by external AC, a lot of the noise went away completely (for radio and screen) - so it may be interference travelling through the power line. This interference does not occur with the OPUS mounted inside the Travla C138 case though (I now use a CarNetix P1900 external to the PC because of better standby support - it feeds into the Travla's built in 120W default ATX DC/DC supply - no interference).

I really don't understand why my custom case had so much interference - I even cut out sheet metal panels for the sides - still did not help. I finally gave up - cause the case was starting to look like Frankenstein Jr. I think the hard drive was the main culprit - I could actually hear static corresponding to hard drive activity!