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Old 07-04-2007, 07:40 PM
Dennis
Dazzled by the Cosmos.

Dennis is offline
 
Join Date: May 2005
Location: Brisbane
Posts: 11,786
Quote:
Originally Posted by AndrewJ View Post
Gday Lester
>snip
Using seperate sets of switched resistors will work, but "you" need to switch them, you have limited settings ( hence can drain a battery when not reqd ), but as a benefit, they will produce no RFI.

PWM controllers allow you unlimited power levels ( almost ), can be easily converted into thermostatically controlled units ( so they only heat when required, thus preserving yr batteries ), but all PWM controllers put out RFI, depending on the type of heater element and wiring used.
This may or may not affect other things nearby.
>snip
Andrew
I heard many years ago, that a popular dew heater controller had the design modified between the Mk III and Mk IV models to either minimise or remove RFI. It seems that some users reported “noise” in their CCD images when using the older controllers.

Cheers

Dennis
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