[Mobile-Portable] NOISE FROM HONDA CRV

[Dan Coleman W8KMX]

Mark:

Many thanks for your comments. About half of what you suggest I have done 
but really have not dedicated an afternoon to experimentation and 
resolution.
I was hoping that someone had done this and I could tag along, hah!

The "gel-cell" source is a great idea. I did not think of that but it will 
be one of the first things I do.  The hustler antenna is "quick disconnect" 
mounted on the bracket welded to the rear door of my CRV (I constructed a HD 
Aluminum bracket that bolts onto the car's bracket).  This is the bracket 
that holds the spare tire and when I quick disconnect the antenna, you can't 
even tell where the mount is.  I did bond the door to the frame (at the 
hinges) but assumed (maybe wrongly) that this connected to the rest of the 
car body.  I will check that.  The coax runs into the rear door, through the 
flex conduit with other wires that go to the rear door and then via the side 
channel to the radio which is under the drivers seat.  The radio is bonded 
to the frame where it is mounted and I run HD wires directly to the battery. 
I have had no difficulty at all in tuning the antennas.  All come to 1:1 
easily and I get very good transmit reports (I guess therefore that RF 
grounding for transmit is good).  The problem is with noise.

Yes, you have the diagnostic of the Fan motor correct.  Any time that motor 
comes on (when the car warms up or AC is turned on) then the noise starts 
etc.

I will try some other ideas you mention and get back with you later.

73,
Dan


----- Original Message ----- 
From: "Mark Schoonover" <schoon at amgt.com>
To: "'Mobile-Portable Reflector'" <mobile-portable at mailman.qth.net>
Sent: Saturday, May 13, 2006 1:58 PM
Subject: RE: [Mobile-Portable] NOISE FROM HONDA CRV


> Dan Coleman W8KMX <mailto:w8kmx at bellsouth.net> tapped at Saturday, May 13,
> 2006 9:54 AM:
>
>> Hello to all:
>> Has anyone successfully reduced/eliminated noise from the Honda CRV?
>
> No, but what you need to do is vehicle independant. Troubleshooting noise 
> is
> the same for any vehicle.
>
>> I
>> would sure like to talk with you.
>> My sources of noise:
>> 1)  AC/Heat causes the most noise.  As best as I can tell it is
>> coming from
>> the DC Fan Motor for the radiator.
>> 2)  Ignition (spark plugs)
>> 3)  Some noise from the windshield wipers.
>>
>> I have done the routine bonding etc and as a test I can disconnect my
>> antenna (quick disconnect at the mount) and I get no noise at all so,
>> I
>> think that nothing is coming in on the DC line.  Agree?
>
> Disagree. If you get no noise at all when disconnecting the antenna, then
> the problem is with radiated noise getting in  through the antenna. The 
> way
> to test if the problem is coming in through the DC power, is to run the 
> rig
> off a gelcel and check for noise.
>
>
>> Any info would be greatly appreciated as I would rather not start from
>> scratch on this.
>
> How have you determined it's the cooling fans for the radiator?? I take 
> it,
> there's no noise when the car is cold, but a soon as the radiator fans 
> turn
> on, you get the noise?? You can try some clamp on ferrite beads on the
> cables that go to the fans. Same with the windshield wipers. If the motor
> housing to the fans is mettalic, you could try bonding them to the body 
> with
> some braid. Windshield wipers can be done the same way. Just unscrew one 
> of
> the housing screws, scrap off the paint around the hole, and attach the
> braid there. Make it short as possible to the body, scrap paint, etc 
> around
> the body screw hole as well.
>
> The other place to ground well is at the feed point. You don't state what
> kind of mount you're using, or COAX. Remember, on these unibody vehicles,
> it's possible that there are seams where various sheetmetal parts are not
> good RF grounds. You could be using just a small part of your vehicle as 
> an
> RF ground. Check out my blog http://ka6wke.blogspot.com for more ideas on
> chasing down noise.
>
> You can do it, just take one step at a time and be patient. Hope this 
> helps,
> if you have more questions, don't hesitate to ask.
>
> 73
>
> Mark
> KA6WKE
> http://ka6wke.blogspot.com
> ----
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