On 26/11/2014 01:22, Phil Allison wrote:
Jeff Layman wrote:

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 ?

See under "Energy efficiency" on page 3 he
http://www.fantasiaceilingfans.com/c...chure-2014.pdf

Also see top of page 2 and section 3 on page 10 he
http://www.fantasiaceilingfans.com/c...tau-manual.pdf

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

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

So it could be that the manufacturer calling it a "DC motor" is being a
bit flexible with the definition?

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

** So the available signal is weak.

Fairly so, but reception is quite acceptable when the fan is off.

The fan is in a new metal-framed conservatory.

** So the signal inside is very weak.

Indeed, even with a loop aerial connected.

--

Jeff