Re: [RFI] Mobile amps and vehicle issues

["FoMoCo EMC" <fomoco_emc@hotmail.com>]

It would be great if auto manufacturers offered that option or even had good 
technical service bulletins to inform you as to what modifications would be 
required to obtain a quieter vehicle.

The trouble is that from an emissions standpoint the vehicle is like an 
onion.  You peel the first layer of noise by elimininating the ignition 
noise.  Now you can hear the cooling fan and fuel pump so you peel that 
layer by fixing those issues.  This keeps going until you finally get to a 
level (layer) that you can tolerate for weak signal work, but by that time 
you have modified the wiring harness, fuel pump, fuel pump driver module, 
cooling fan control module, engine control module, ignition coil, plugs, and 
ignition wires.

The cost of having this level of differentiation is large enough that when 
weighed against the benefit of the added sales from the option that it is a 
loss to the manufacturer.  With the manufacturers in red ink anything that 
adds cost is carefully scrutinized.

Still the best bet for resolving these issues is through forums like 
rfi@contesting.com.   The manufacturers can't offer the help at the level 
that most hams need.  Call any of the manufacturers and they will tell you 
to take it up with the dealer and then when it appears as a blip on the 
monthly warranty reports there might be some resolution coming from the 
factory.

EMC Guy

> From: David Jordan <wa3gin@erols.com>
> To: FoMoCo EMC <fomoco_emc@hotmail.com>
> CC: rfi@contesting.com
> Subject: Re: [RFI] Mobile amps and vehicle issues
> Date: Wed, 11 Jan 2006 13:23:07 -0500
>
> H EMC GUY,
>
> Hey,
>
> Ford should consider offering the option for better noise suppression.  
> Most mobile rigs are costing over $1,000 bucks these days and on-board 
> computer controllers can be equally expensive.  I think Ford might be 
> surprised just how many radio operators would be willing to spend another 
> $50 or $100 bucks to ensure a relatively noise free and safe ride!
>
> I've got the noise reduced so much in my Sport Trac I can hear the noise 
> from the anti-lock brake sensors on my AM radio, haha.
>
> 73,
> dave
> wa3gin
>
> FoMoCo EMC wrote:
>
> > It may be shameful but it is going to be the shape of things to come.
> >
> > Susceptible circuitry is rampant in a vehicle.  Almost every electric 
> > motor in a vehicle is speed controlled by a pulse width modulated signal.  
> > A little bit of RF into the circuit and the motor will exhibit undesired 
> > RPM variations.  There are a dozen sensors on the engine and throughout 
> > the vehicle that put out low level signals that can be disrupted.  Imagine 
> > what occurs when the vehicle can no longer tell if tire rotation is 
> > occuring (wheel speed sensors) or can't determine the postion of the 
> > camshaft, crankshaft, or throttle plate.

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