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Fan Noise On the on the carrier

 
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Fan Noise On the on the carrier
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stylzmovement
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Post Fan Noise On the on the carrier Reply with quote
i have a transmitter here , there are 3 dc 12 volts fans in the unit where ever the unit is on , ( no audio ) i will hear the fan noise on the carrier ( the fm Frequency is 106.1 fm ) .
what can get rid of the noise from getting into the audio on the frequency?
Tue Feb 12, 2008 11:38 am View user's profile Send private message
pcs
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Joined: 18 Jan 2002
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Location: Radio Land

Post Reply with quote
Easiest fix is to power fans from separate source.

Another fix is to power fans from mains, if mains is available inside the box.

Marko

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Marko - PCS Electronics
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Tue Feb 12, 2008 2:24 pm View user's profile Send private message Visit poster's website
stylzmovement
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Post Reply with quote
that mean the fans will be now has to be ac fans ..
are there any choke that i can use.
Tue Feb 12, 2008 11:21 pm View user's profile Send private message
pcs
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Post Reply with quote
Yep, LC filters might help as well, and routing fan wires as far away as possible from other stuff.

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Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Wed Feb 13, 2008 12:25 am View user's profile Send private message Visit poster's website
stylzmovement
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Joined: 11 Oct 2003
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Post Reply with quote
ok, if i use a LC Filter , that will be for the RF, but the fan noise will still fall between the audio frequencies of 20Hz to 20Khz.
what i am looking for is something to stop or reduce the fan noise from the audio , i cannot use ac fans due to no available fans with the specified CFM.

so are there something like air core to reduce the noise?
Tue Mar 03, 2009 4:30 pm View user's profile Send private message
pcs
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Joined: 18 Jan 2002
Posts: 3063
Location: Radio Land

Post Reply with quote
LC filter will help, try it. Caps should be of the 1nF, 100nF, and 100uF values,
in parallel. RFC (coils) should be about 220uH or so, permitting sufficient
current without heating.

If you're using MAX PRO 3+ replace it with 3000+ model, you will notice the noise
is not there anymore at all.

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Sun Mar 08, 2009 4:37 pm View user's profile Send private message Visit poster's website
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