Alt. noise

arlojanis · Post by **arlojanis** » Thu Sep 12, 2002 7:59 am

I have a UHF, 40 watt, 4 channel, M1225 installed in a 2002 Ford van. The alt. noise is very bad. I have installed a Motorola filter at radio, and it helped a little. I am going to try another filter at the battery. Any other suggestions?

bernie · Post by **bernie** » Thu Sep 12, 2002 2:20 pm

Is this noise on receive, and transmit or what?
Is this " noise " a whine that varies with engine speed
or somthing else?
I presume that the noise is on the power leads, but there are other possibilities.
I note that the Mitrek will get noisy if the case is not grounded. I had noise capacitively coupled into the circuits.
Perhaps the case needs grounding.
The accessoty fuse box is likely the worst place to connect somthing that may be sensative to line noise.
The radio power should come from the battery.
Rather than connecting to the battery terminal,
use the terminal that the battery is connected to.
There is usuially a start relay on Fords.
Another problem could be that there is a poor connection between the engine/battery and frame.
Although this is a new vehicle, an open diode in the alternator will give you a whine, as will a failing battery.
aloha, Bernie

jim · Post by **jim** » Thu Sep 12, 2002 7:32 pm

Do a voltage drop and check for ground loops between the battery (-) to chassis and to the radio (-) and the radio ground.

chpalmer · Post by **chpalmer** » Sat Sep 21, 2002 7:55 pm

1225's are great for this, they will bring out any and all imperfections in your electrical system... Good Luck

calif dave · Post by **calif dave** » Sat Oct 12, 2002 10:39 pm

I had a 70s Dodge Power Wagon that used to whine in my VHF. I tried alot of fixes, Then I found there was a ground strap from the hood to the fire wall that had rusted out.

Also disconnect the ant. and see if the noise goes away. check the coax make sure it is good. also all ant and gnd connections.