Radio interference from 12v fan.

[Rural QLD CC]

Greetings,
I've just installed a car stereo and I'm getting massive
interference from the 12v fan on the front of the A/C condensor. It's not
line noise though......it's actual RF interference. As soon as the fan
starts, the reception is so bad that it's almost like I've unplugged the
aerial! I've tried re-routing the aerial cable etc (even tried standing
next to the car with the aerial in my hand) to no avail. It reduces the
static, but doesn't eliminate it.

What options do I have here? Is it possible that the 12v fan is faulty in
some way? Surely these things shouldn't broadcast that much RF noise!?!

MrBonk
www.mrbonk.com

[JD]

Rural QLD CC wrote:

> Greetings,
> I've just installed a car stereo and I'm getting massive
> interference from the 12v fan on the front of the A/C condensor. It's not
> line noise though......it's actual RF interference. As soon as the fan
> starts, the reception is so bad that it's almost like I've unplugged the
> aerial! I've tried re-routing the aerial cable etc (even tried standing
> next to the car with the aerial in my hand) to no avail. It reduces the
> static, but doesn't eliminate it.
>
> What options do I have here? Is it possible that the 12v fan is faulty in
> some way? Surely these things shouldn't broadcast that much RF noise!?!
>
> MrBonk
> www.mrbonk.com

Try fitting a coaxial in-line suppression capacitor right at the fan. Also
check the earthing of the antenna coax at the antenna.
JD

[atec]

Rural QLD CC wrote:
> Greetings,
> I've just installed a car stereo and I'm getting massive
> interference from the 12v fan on the front of the A/C condensor. It's not
> line noise though......it's actual RF interference. As soon as the fan
> starts, the reception is so bad that it's almost like I've unplugged the
> aerial! I've tried re-routing the aerial cable etc (even tried standing
> next to the car with the aerial in my hand) to no avail. It reduces the
> static, but doesn't eliminate it.
>
> What options do I have here? Is it possible that the 12v fan is faulty in
> some way? Surely these things shouldn't broadcast that much RF noise!?!
>
> MrBonk
> www.mrbonk.com
>
>
try running a moderate size cap to ground . 470 mic or bigger and at
least 24v.. should help it... for the $2.00 its worth a try

[feral]

Rural QLD CC wrote:
> Greetings,
> I've just installed a car stereo and I'm getting massive
> interference from the 12v fan on the front of the A/C condensor. It's not
> line noise though......it's actual RF interference. As soon as the fan
> starts, the reception is so bad that it's almost like I've unplugged the
> aerial! I've tried re-routing the aerial cable etc (even tried standing
> next to the car with the aerial in my hand) to no avail. It reduces the
> static, but doesn't eliminate it.
>
> What options do I have here? Is it possible that the 12v fan is faulty in
> some way? Surely these things shouldn't broadcast that much RF noise!?!
>
> MrBonk
> www.mrbonk.com
>
>
One or some of these may help you.

> http://www.autospeed.com/shop/category_1406/browse.html


--

Take care,
Feral

[atec]

Rural QLD CC wrote:
> Greetings,
> I've just installed a car stereo and I'm getting massive
> interference from the 12v fan on the front of the A/C condensor. It's not
> line noise though......it's actual RF interference. As soon as the fan
> starts, the reception is so bad that it's almost like I've unplugged the
> aerial! I've tried re-routing the aerial cable etc (even tried standing
> next to the car with the aerial in my hand) to no avail. It reduces the
> static, but doesn't eliminate it.
>
> What options do I have here? Is it possible that the 12v fan is faulty in
> some way? Surely these things shouldn't broadcast that much RF noise!?!
>
> MrBonk
> www.mrbonk.com
>
>
by the way thats from the b+ to ground

[John_H]

Rural QLD CC wrote:
>
>What options do I have here? Is it possible that the 12v fan is faulty in
>some way? Surely these things shouldn't broadcast that much RF noise!?!

Connect a supressor capacitor from the fan terminal (or as close to it
as possible) to chassis. Any auto electrical supplier should stock
them, or you can get one off the back of a disused alternator (which
will also create heaps of RF interference without it).

It's not a particularly unusual problem.

--
John H

[Bernd Felsche]

JD <jjd@SPAMLESS.com.au> writes:
>Rural QLD CC wrote:

>> Greetings, I've just installed a car stereo and I'm getting
>> massive interference from the 12v fan on the front of the A/C
>> condensor. It's not line noise though......it's actual RF
>> interference. As soon as the fan starts, the reception is so bad
>> that it's almost like I've unplugged the aerial! I've tried
>> re-routing the aerial cable etc (even tried standing next to the
>> car with the aerial in my hand) to no avail. It reduces the
>> static, but doesn't eliminate it.

>> What options do I have here? Is it possible that the 12v fan is
>> faulty in some way? Surely these things shouldn't broadcast that
>> much RF noise!?!

>Try fitting a coaxial in-line suppression capacitor right at the
>fan. Also check the earthing of the antenna coax at the antenna.

Make sure that the fan's chassis ground is good. It may be through
sheet metal in the radiator mount/slam panel which is not really
electrically sound; just cheap. If need be, run a heavy ground cable
directly from the fan back to the ground strap at the battery.

To check, find where the fan's ground connects and use a start
jumper cable clipped on from there back to the battery post.
--
/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia
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