Good suggestion: You might also try bringing the hot spot to chassis ground by tightly wrapping a 1" braided shield around the bundle of wire - three inches to either side of the hot spot and securing one end of it to chassis ground making sure not to inhibit air flow.
I would not suggest wrapping electrical tape or anything else around the entire braid as this will cut off the ability of the braid to breathe and could cause problems in your wiring harness if the vehicle gets too hot (melting - merging - ect.) But wrapping it only around at each end is a quick and effective way to secure it to the harness and still allow for air to flow and heat to escape. We used this as an effective method in EMC when hard wiring harnesses on government test vehicles at SW Research Institute during an experiment many times. It is quite cost effective and detunes the wiring (antenna) rather well so it can not radiate. Although it is possible for it to pop up magically in other locations after it is done at that location. But your spectrum analyzer should be able to tell you that if it happens. TNX, BOB KE5CTY (old calls - WB5ZQU - WY5L) http://www.qsl.net/ke5cty -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Mike Pugh Sent: Wednesday, May 25, 2005 5:07 PM To: [email protected] Subject: Re: [Repeater-Builder] OT:Interferrence Help Years ago, the 2 way shop I was working in ran into the same issue with a truck in a fleet that we took over. The previous shop had just detuned the receiver to the point that it was nearly deaf, but since it was a city utility truck that ran around under a repeater, the symptoms were so masked that the customer thought it was fixed. Anyway, we ended up calling GMC (it was a Chevy truck) and they had a factory bulletin on how to fix this. The result as I recall was that it was a master reference oscillator in the computer. The fix was to obtain a free xtal from GMC to change the clock speed, and therefore move the birdie to another, non interfering frequency. Crude, but it worked.. Mike Pugh KA4MKG Tim S. wrote: > This is a little off topic but I could use some help. > > I am working on a fire truck that is getting interferrence on the VHF > (156.075mhz) from the trucks wiring. > > If I put an HT near I get the interferrence on the HT. When I > disconnect the battery it goes away. > > We removed one fuse at a time and it went away when we pulled the fuse > to the trucks computer ECM module. > > We tried an ECM module from another truck w/o the interference problem > and we still had it in the bad truck. > > Next I tried sniffing around with a spectrum analyzer and found the > highest noise near a large bundle of vehicle wiring. We are talking a > tightly bunched 2-3 inch bundle. > > Tried adjusting the squelch to open at .5uV but that did not help. > > Need some idea on how to proceed. > > Thanks > > Tim > > > > > > > > Yahoo! Groups Links > > > > > > > > Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
