Gore-Tex might let moisture out, but it might let it in. Moisture migrates from the more humid side of the membrane to the less humid side. It is a pretty slow process.
wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On Jan 20, 2016, at 11:39 PM, Ian White <gm3...@ifwtech.co.uk> wrote: > > The key point about a semi-permeable vent is that it blocks liquid water > (and insects) from getting into the enclosure, but *always* allows water > vapor to escape. As David points out, plain mesh won't do that under > all conditions. > > In the UK, an equivalent to the Gore-Tex engineered vents is available > from Farnell for about £5 ($7.50). Part numbers 2308394 (black) or > 2308395 (grey). > > CPC normally has them a little cheaper (part numbers EN83188 or EN83189) > but they are currently out of stock. > > Compared with the value of the KAT500 inside the enclosure, a properly > engineered semi-permeable vent is a very good investment. > > > 73 from Ian GM3SEK > > >> -----Original Message----- >> From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of >> David Cutter >> Sent: 21 January 2016 07:08 >> To: Lewis Phelps; Elecraft@mailman.qth.net >> Subject: Re: [Elecraft] Remoting KAT500 to base of antenna >> >> Yes, but the weight of water eventually pushes it through - it's cheap > but >> not perfect. If you use a 20mm fitting as I did back then, water > accumulates >> inside until a large droplet forms then exits. The Gortex is better but > more >> $ £. >> >> David, G3UNA >> >> >> ----- Original Message ----- >> From: "Lewis Phelps" <l...@n6lew.us> >> To: <Elecraft@mailman.qth.net> >> Sent: Wednesday, January 20, 2016 8:03 PM >> Subject: Re: [Elecraft] Remoting KAT500 to base of antenna >> >> >>> But might not this re-introduce the surface tension problem? >>> >>> Lew N6LEW >>> >>> >>>> On Jan 20, 2016, at 10:18 AM, David Cutter <d.cut...@ntlworld.com> >> wrote: >>>> >>>> From my work in the food industry (if memory serves), critter > invasion is >>>> prevented with 0.64mm square nylon netting. This is common in the >>>> dress-making industry. (I think it can also be found as a stainless >>>> steel gauze). This can be glued over a breather (drip) hole in the > base. >>>> >>>> David >>>> G3UNA >>>> >>>> >>>> ----- Original Message ----- From: "Edward R Cole" > <kl...@acsalaska.net >>>> <mailto:kl...@acsalaska.net>> >>>> To: <Elecraft@mailman.qth.net <mailto:Elecraft@mailman.qth.net>> >>>> Sent: Wednesday, January 20, 2016 8:29 AM >>>> Subject: Re: [Elecraft] Remoting KAT500 to base of antenna >>>> >>>> >>>>> Fred, >>>>> >>>>> Your high desert climate will probably produce less condensation > than >> my >>>>> sub-arctic/maritime environ. What I do for enclosures is to not > seal >>>>> them airtight but provide good drain openings which air can > exchange. >>>>> Of course the shelter is made to repel direct rain/snow. >>>>> >>>>> I suspected that my TR relays were "freezing up" at lower temps > making >>>>> the action delayed so I used some big aluminum Dale resistor > strapped >>>>> onto the relays to add direct heat by conduction. I happen to have > 28v >>>>> equipment so used 28v thru the resistors to produce heat within > their >>>>> wattage rating (used 40w resistors at both relays). Of course this > also >>>>> provided some heating of the ambient air of the enclosure which > helped >>>>> keep moisture from forming even in 90% humidity of the fall. It > rains >>>>> 8-days with one day off from August to October when temps finally >> drop >>>>> below freezing and rain becomes snow. You don't have anything near >>>>> that. >>>>> >>>>> One thing I have noticed about drain holes in some equipment is > they >> are >>>>> too small to allow water to drop free due to surface tension and in > my >>>>> environ that results in the weep holes freezing tight. I drill > them out >>>>> to 1/4 inch. Of course if you are prone to insect/archnid invasion > that >>>>> is problematic. >>>>> >>>>> PS: I lived five years in the high Mojave Desert so know all about >>>>> "critters of the desert" (never stick your hand into a confined > space >>>>> before kicking it to see what crawls out or "rattles"! >>>>> >>>>> 73, Ed - KL7UW >>>>> ------------------------------------------ >>>>> >>>>> 3. Reno/Sparks is a high desert [4,500'] directly adjacent to the >>>>> Carson Range and Sierra Nevada [really big mountains]. Winter > temps >> go >>>>> down into single digits, it does snow/rain. Should I do anything > to >>>>> prevent condensation in the weatherproof box [light bulb, drain > hole, >>>>> ???]. >>>>> >>>>> 73, >>>>> >>>>> Fred K6DGW >>>>> - Northern California Contest Club >>>>> - CU in the Cal QSO Party 1-2 Oct 2016 >>>>> - www.cqp.org >>>>> >>>>> >>>>> 73, Ed - KL7UW >>>>> http://www.kl7uw.com >>>>> "Kits made by KL7UW" >>>>> Dubus Mag business: >>>>> dubus...@gmail.com >>>>> >>>>> >> ______________________________________________________________ >>>>> Elecraft mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:Elecraft@mailman.qth.net >>>>> >>>>> This list hosted by: http://www.qsl.net >>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>> Message delivered to d.cut...@ntlworld.com >>>>> <mailto:d.cut...@ntlworld.com> >>>> >>>> >> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> <http://mailman.qth.net/mailman/listinfo/elecraft> >>>> Help: http://mailman.qth.net/mmfaq.htm >> <http://mailman.qth.net/mmfaq.htm> >>>> Post: mailto:Elecraft@mailman.qth.net >> <mailto:Elecraft@mailman.qth.net> >>>> >>>> This list hosted by: http://www.qsl.net <http://www.qsl.net/> >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> <http://www.qsl.net/donate.html> >>>> Message delivered to l...@n6lew.us <mailto:l...@n6lew.us> >>> Lew Phelps N6LEW >>> Pasadena, CA DM04wd >>> Elecraft K3-10 / KXV144 / XV432 >>> Yaesu FT-7800 >>> l...@n6lew.us >>> www.n6lew.us >>> >>> Generalized Law of Entropy: Sooner or later, everything that has been > put >>> together will fall apart. >>> >>> >>> >>> >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Elecraft@mailman.qth.net >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to d.cut...@ntlworld.com >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to gm3...@ifwtech.co.uk > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to wun...@wunderwood.org ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
