[Elecraft] Fan Noise Solution

[Stuart Rohre]

Fan fixes in general for small muffin fans.

The sizing of a fan and its enclosure can produce resonances like a speaker
cabinet to increase the apparent fan noise.  The movement of blades in air
can also contribute a large measure of noise because of high tip velocities.

some fan coupling to a cabinet can be isolated by mounting the fan on rubber
grommets and weather stripping to maintain the air seal.

As small fans age, they inevitably get noisy, and most have a stick on label
over the end of the blade shaft as it rides in a simple cheap sleeve
bearing.

The lubricant is light oil or grease that dries out.  The fix is to spray in
Tri Flo an oil containing microscopic ball bearings of teflon, to quieten
the fan for another couple years.  Replacement fans with ball bearings are
generally longer lasting and maybe be quieter.
-Stuart K5KVH