View Full Version : Wierd grounding issue

04-01-2014, 01:26 PM
So I installed a conra 29 NH ST about a week ago in my 94 nissan pathfinder. I drilled a hole in the passenger side quater panel and placed the stud through it, ran the wire through a door grommet to the back of the radio in my dash and then soldered a new pl-259 connector on (it broke at one point) i tested my solder job with the multimeter and was reading inf ohms. As well I soldered the power adaptor to the back of my cigarette lighter.

While tuning the radio the swr was always relatively high but never quite over three, then later was always around 3. While with a friend we determined that he couldnt hear me from over 15 feet away. after swapping antennas and playing around I tried to calibrate again however my needle would not go all the way to the right where the 'cal' arrow is. I may have got it there once or twice however the swr was still above 3.

So upon many google searches and youtube videos I had figured out all the little tests to do on mounts, cables etc. My top nut on the quarter anel (the one the antenna screws into) has a ground (bad thing i hear). SO i did aquite a bit to make sure the bolt from the lower nut isnt touching the frame and tested it in isolation. it is fine.

The coax cable leading to the antenna showed a continuity reading from shell to the pin (bad thing) so I started pulling EVERYTHING out to test all points in isolationg and finally I have narrowed it down to either my radio or my power supply:

When the coax is plugged into the radio but there is no power cord in the radio everything is fine! ie the coax shows zero resistance from shell to pin and the upper stud is not grounded. Good thing.

Now when I plug the radio in (with radio off and ignition off, or atleast on acc; which doesnt oermit power) everything goes to hell. The top stud is grounded and the coax shows a zero reading on ohms from pin to shell. I tried a different power cord (the kind that plugs into cig lighter) and same thing happens.

So is it possible for a faulty radio to do this? or was my solder job to the power supply just that bad???

Gordon Gekko
04-02-2014, 03:00 PM
Shitty install. The antenna and/or coax is shorting out.