radio question

Axkicker · 04-27-2001, 12:56 AM

when the computer is off the radio reception is great but when the computer is on the reception gets crappy. Anyone know a fix for this?

wizardPC · 04-27-2001, 09:52 AM

if the computer is close to the radio, then it might cause interference. It could aslo be a ground loop, so check that your case, power supply, and inverter are properly grounded.

Aaron Cake · 04-27-2001, 05:06 PM

Ground loop isolator?

Without knowing more about your setup, it is hard to suggest something.

Axkicker · 04-27-2001, 11:08 PM

the radio is no where by the computer. The computer is in the trunk. the radio is in the fron (where else would it be) all the electrical is run separately from the audio. And everything is grounded to the same point. And I am useing Dc to dc power supply. I think the computer is drawing too much power. I have the same problem at home when I am using my computer. The radio loses reception. They are both plugged into the same outlet. Anyone else experience this ? If not what is different from your setup ?
Thanks for the help.

Bj · 04-28-2001, 11:44 AM

It's to do with the clock frequency of your cpu. You see, it generates harmonics at certain frequencies around the core frequency, so if your CPU is 133mhz, then if will create noise at and 1/4 less and 1/4 past this point....all over the spectrum, it's just the amplitude of these niose spkies that varies.... It's hard to explain, but it means that the bus noise and other noisy things in your pc, will create noise on your radio frequency range 88 - 108mhz, from the puter. There isn't much you can do about this, because the noise is so strong....

You can try shielding your PC better, keeping your radio antenna away from any Bus runs, like Parallel port cables etc. The key is to allow your radio to pick up the radio station BETTER than it hears your PC's "radio staion" (harmonic output).

You can switch to a faster CPU, as this then shifts the harmonics up to the 200mhz region (and away from your fm radio recption area 88- 108mhz) of your CPU. If say you use a 600mhz or so CPU, then this won't be a problem for your radio, but that may be a bit expensive

The best thing is just to sheild everything, and get a good radio with a good signal to noise ratio on the RF front end.

Most people won't have this problem, unless their car antenna in on the boot fender....
This is just a nightmare!

So try under clocking your cpu, or a better radio... but I presume that your CPU is around the 100 to 200 mhz range if you are getting noise...

What sort of setup do you have? ie cpu speed? casing? PSU? lcd/tft?

Martin S. Shepherd · 04-28-2001, 04:09 PM

If you take BJ's advice concerning buying a more powerful CPU and price is an issue then I have a few suggestions. The first is to try ebay. The second is depending on your location there may be a "second hand" computer store. I live in Austin, Tx. and we have several (although we are rapidly becoming Silicon Valley's little brother). I purchased my Pent. 266 for about $20.00. The good thing about buying it there is that they normally give you some sort of warranty that it will work and you don't have to mail it in to get another one. Also, see if there is a Goodwill Computers in your area. We have one here and you can buy older computer components very cheaply (no warranty).

Also try sheilded wiring. I have a local store called Tinkertronics which has all sorts of components, including premade sheilded multi-strand wiring. I am about to install my comp. and all the wires will be in one bundle from my comp. to the back of the dash.

Axkicker · 04-28-2001, 06:15 PM

It is a 600MHZ Duron processor. 66 mhz bus speed. And the reciever is a kenwood 716s. Any ideas ?

Axkicker · 04-28-2001, 06:17 PM

and a 6.5 tft touchscreen