Reply: [RFI] Unknown RFI from truck when in motion but in neutral
Morse, Earl (E.A.)
emorse at ford.com
Mon Mar 24 08:56:37 EST 2003
Dave,
>From what you have said two mechanisms come to mind.
This could be tire static. As the rubber rolls along the road it develops a charge which discharges and forms a static noise. This is unlikely with stock tires as they are specified to have enough internal resistance so as to drain off this charge as it forms.
A more likely culprit would be the Antilock Braking System (ABS) and its wheel sensors. These sensors detect wheel motion and employ the ABS when the wheels are not all rotating at the same speed.
There are 3 of these sensors: one on each of the front wheels and a third monitoring the rear axle. These sensors receive siganling from the ABS module so it could also be part of the problem.
Earl N5TU
Date: Fri, 21 Mar 2003 20:20:37 -0500
From: David Jordan <wa3gin at erols.com>
To: "rfi at contesting.com" <rfi at contesting.com>
Subject: [RFI] Unknown RFI from truck when in motion but in neutral
Message-ID: <3E7BBA65.4020702 at erols.com>
Content-Type: text/plain; charset=us-ascii; format=flowed
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Precedence: list
Message: 3
Hi Folks,
Found an interesting problem while listening to AM 630 all news station
here in WDC.
Getting loud clicking noise. Sounds very much like spark plug noise but
when coasting at 30mph and placing the engine in neutral such that the
engine RPM drops from 2500rpm to idle, the ticking noise remains at
speed. However, as the vehicle slows down the noise also slows down. I
can rev up the engine while it remains in neutral but the speed of the
noise doesn't change. Is there some type of speed or other monitoring
devices on the wheels of the 2001 Explorer that is sending RF signals to
the on-board computer? This one is got me scratching my head.
thoughts,
dave
wa3gin
------------------------------
Date: Fri, 21 Mar 2003 22:22:17 -0800
From: Jim Smith <jimsmith at shaw.ca>
To: "rfi at contesting.com" <rfi at contesting.com>
Subject: Re: [RFI] Unknown RFI from truck when in motion but in neutral
Message-ID: <3E7C0119.2040800 at shaw.ca>
References: <3E7BBA65.4020702 at erols.com>
Content-Type: text/plain; charset=us-ascii; format=flowed
MIME-Version: 1.0
Content-Transfer-Encoding: 7BIT
Precedence: list
Message: 4
Hmm.... I may be way off base here but I seem to recall from 35 years
ago that hams would squirt graphite powder into the interior of their
tires to eliminate noise produced by a mechanism that I no longer
recall. Maybe an urban myth. No doubt others can give better info.
FWIW de Jim Smith VE7FO
------------------------------
Earl Morse
EMC Engineering
Bldg 5, Cube 2E104
Phone: 313.323.7968
Fax: 313.390.5327
More information about the RFI
mailing list