Hi All,
Some comments for the group:
It would be difficult to put enough silica gel inside an enclosure to
absorb all of the moisture over the lifetime of the outside tuner. I
don't care how fine a screen you find, there's a critter or baby critter
who will crawl through it. The solution to that problem is to use a
cotton ball. It breathes and critters absolutely cannot get through
it. (There's a cotton ball allowing your electric meter to breathe and
keep out critters right now.) I wouldn't recommend sealing an
enclosure. Even if you seal it on a dry day, the atmosphere that gets
trapped inside will eventually reach the dew point and it will "rain"
inside the enclosure. Better to vent it to the atmosphere, keep rain
from getting inside, and keep the critters out with cotton balls. The
real worry is what surface finishes are used inside the tuner and how
resistant are those finishes to normal humidity. 73, Tim, W2UI
Dr. Gerald N. Johnson, electrical engineer wrote:
> The enclosure needs a vent else there can be a condensation problem. The
> vent needs to be effectively screened so insects and critters don't call
> the enclosure home. Power to operate the logic of the tuner made for
> indoor use may be a slight bother, though the 120 volt outlet with GFCI
> should be reasonably safe.
>
> Alternatively, the tuner enclosure can be tightly sealed but then needs
> some humidity control like a handful of silica gel to prevent
> condensation on the circuits at low air temperatures. Or some external
> heat applied to keep the enclosure above a condensation temperature.
>
> Where there's fog and a vent, a bit of heat in the enclosure might not
> be a bad idea either to keep the circuits dry.
>
> 73, Jerry, K0CQ
>
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