The solution to your noise problem is simple and fairly cheap. Replace the
current cooling
fan with a 12 VDC tube axial fan such as is used on computers and other Ham
radio
gear. You can then add some type of voltage control on it so it only runs
just as fast
as is needed. Just power it up from the 12 VDC you already have at the
station.
These fan are available in all kinds of sizes and CFM ratings. Some sizes
are so small as to make it easy to place a small fan on each of the three
811A's.
These fans can be purchased new for 20 dollars and less. Go to:
http://www.alliedelec.com
http://www.mouser.com
Agusta is one brand that I have used they are quiet and very reliable and
cheap.
There are many others.
Hope this helps.
Ken de W7ITC
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