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
