I'm trying to install a Midland 79-290 and am getting loads of interference from the running motor. It's interesting that it doesn't change pitch when the RPM changes so it's probably not alternator noise. I'm pretty sure I've got a decent antenna ground. My channel 1 and 40 SWR is tuned to 1.5. Channel 19 is 1.1. I'm using a 3-foot firestik tunable mounted at the driver-side rear roof rack (just like the example here. Same bracket but no fold-down mount. I have the stick right in the stud.
Anyway, when you turn the key to ON, I get a whine for a few seconds, then a relay clicks and it goes away. That's probably a fuel pump, I figure. When I start the motor it somes back but sounds a bit different.
If I disconnect the stick from the mount, it goes silent. Does this tell me that it's not noise from the power source (currently testing using from 12V outlet)? If I touch the stud I get some of the interference, but not as high intensity as through the whip.
I also have a magnetic mount with another antenna lead. I get the same interference using it so it's not the coax I ran.
I'm pretty disappointed. AM sucks.
Any pointers helpful. I'm strongly suspecting the fuel pump.
More info after further testing. If I pull the fuel pump fuse with the enging running I an treated to interference-free reception. Plug it back in and the noise returns so I'm convinced I've found the source. Also, this occurs using my handheld unit connected to the antenna I ran so it's not coming through the power source. It's being picked up by the antenna.
No idea what to do to fix it. Would anyone consider this a warranty issue?
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"[Pa] always reloaded the gun as soon as he had fired it, for, he said, he did not want to meet trouble with an empty gun." -- Laura Ingalls Wilder
[This message has been edited by CJLinst (edited 04-29-2001).]
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