CORRECTION: "blew the cover off" should have read "damaged the cover gasket".
On Thu, Oct 31, 2019, 12:13 PM Mike Waters <[email protected]> wrote: > If you want to use dessicant, then you should use a suitable > hermetically-sealed pressure equalizer. This keeps the pressure inside the > box always the same as on the outside, regardless of air temperature or > barometric pressure. Thus, no water vapor can enter. > > These are available commercially. > (Sorry that I don't have a source, p/n, or price.) > > But you can make your own pressure equalizer. The way I've always done > that is to fill the tip jacks full of silicone dielectric grease. This > non-hardening grease acts like a piston, moving in and out as the > barometric pressure changes. > > These tip plugs are connected to the Beverage antenna itself with a short > length of #18 flexible copper wire. After you fill the jacks full, then > fill the inside of the tip plug as you assemble it to prevent corrosion. > Finally, slather more of it both on top of the jack and on the plug itself > just before you plug it in. > > I've done that for ten years now, and only had to replace the dessicant > bag once. That was after lighting damaged the jacks and blew the cover off > (before I started using 90v GDTs). > > I don't know why banana connectors wouldn't work just as well as tip > plugs. I just used tip connectors because that's what I had. Banana plugs > are sturdier. > > In lieu of --or perhaps in addition to-- these plugs, one could use a > short length of 3/16" or 1/4" UV-proof tubing filled with this > non-hardening grease. > > Note that the box should not be too large inside, lest too great a > quantity of air --from both temperature or atmospheric air pressure > changes-- move the equalizer "piston" too far, thus ruining the hermetic > seal. > > For my Beverage boxes, I use those Hammond enclosures with a rubber seal > between the box and the clear polycarbonate cover. > > 73, Mike > W0BTU > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
