[Mobile-Portable] More noise cures

[N5WV]

Earl , There is no noise above 30mhz. So public safety land mobile does not have a problem. Only a few government vehicles have hf radio. And most use gasoline engines.There is no diesel powered suv produced in the US since the Ford Excursion ended in 2005. Diesels were the quietest with no spark plugs years ago but when electronic fuel injection came out all that changed. Diesels are noisier than gas engines now. Thanks for the comments , Randy N5WV 

----- Original Message -----
From: "Earl Needham" <earl.kd5xb at gmail.com> 
To: "Mobile-Portable Reflector" <mobile-portable at mailman.qth.net> 
Sent: Sunday, January 19, 2014 1:26:39 PM 
Subject: Re: [Mobile-Portable] More noise cures 

Seems like Ford should have a procedure to make the vehicle useable for 
public safety, utilities, etc. If you were to ask the right person, you 
could probably avoid a whole lot of trial and error. 
Vy 7 3 
Earl 
KD5XB 



On Sun, Jan 19, 2014 at 11:52 AM, <N1KHB at aol.com> wrote: 

> Randy and all, 
> I just plugged in a search phrase of "fuel injector electrical noise 
> radiation" and received enough potentially useful returns that it appears 
> hopeful that some of the authors might have some experience. I didn't read 
> any, but the titles suggest promise. 
> And just off the top of my head, I'm thinking back to my electronics 
> experience. One of my solenoid (an injector is a solenoid, right?) 
> projects 
> which radiated unacceptably was tamed with ceramic bypass caps. Think 
> risetime and thus bandwidth reduction here. And way back in tech school 
> we were 
> told that connecting reverse biased diodes across relay and solenoid coils 
> never hurt and usually helped. The coil resonates when power is removed 
> abruptly and the first reverse alternation is greatly suppressed by the 
> diode 
> becoming forward biased in that phase thus quickly killing the noise 
> burst. 
> I don't know if vehicle companies have either, or any, such 
> suppression. Something to investigate I suppose. 
> 
> Best, 
> Sonny N1KHB 
> 
> 
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