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Phil Allison[_3_] Phil Allison[_3_] is offline
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Default Fan causing MW RFI

Jeff Layman wrote:


The only thing I can get in the next day or so is this delta suppression
filter:
http://www.maplin.co.uk/p/delta-supp...n-filter-rg21x


** That should do OK.



I expect the fan motor is a BLDC type, possibly operating at mains
voltage, and the pitch of the noise on AM would vary with its speed.


Guess so. The fan often turns in the reverse direction for a second or
so when switched on, then corrects itself.


** Really ?

What makes you sure it is a DC motor ?

DBDC motors are really AC motors with in-built electronic drives.

Motors that power ceiling fans are normally multi-pole induction types - fully reversible.



No. The 999kHz local radio transmitter (1kW) is about 15 km away..


** So the available signal is weak.



The fan is in a new metal-framed conservatory.


** So the signal inside is very weak.


.... Phil