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On 30/11/2020 22:08, Lester Veenstra via time-nuts wrote: > This brings up a point I have made frequently, in my professional life. > Do not try to seal in electronics (for me , satellite units mounted near or > on the feed system) instead warm the area with electronics and place a weep > hole at the low point. Short of true hermetic seals, any other gasketed box > will inhale water vapor, condense it on the cooler surface, and collect > inside as water over time. Much better to let the enclosure breath a bit > and drain as needed. The hole should not be subject to external rain > encouraged to come un, and of course, prevent insects from nesting. Most > active electronics will naturally form a warmer area, discouraging > condensation. > > Lester B Veenstra K1YCM MØYCM W8YCM 6Y6Y > [email protected] > > 452 Stable Ln (HC84 RFD USPS Mail) > Keyser WV 26726 > > GPS: 39.336826 N 78.982287 W (Google) > GPS: 39.33682 N 78.9823741 W (GPSDO) > > > Telephones: > Home: +1-304-289-6057 > US cell +1-304-790-9192 > Jamaica cell: +1-876-456-8898 > > > > -----Original Message----- > From: time-nuts [mailto:[email protected]] On Behalf Of Art > Sepin > Sent: Monday, November 30, 2020 4:23 PM > To: Poul-Henning Kamp; Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] EOL Motorola Oncore Remote Antenna > > >> To me it looks more like water ingress through micro-cracks in the >> plastic-dome, and the O-ring did its job and kept that water in. > Interesting. That's the first we've heard about micro-cracks in the Radome > but that's certainly a likely possibility with such a long exposure to U/V. > The more common failure mode reported was moisture ingress due to > "breathing;" the uptake of moisture laden air past the O-Ring, due to a > small pressure differential. But, once the moisture was inside, it was also > trapped internally by the O-Ring. This condition was reported more often in > geographic areas that experienced a wide variation in barometric pressures. > > > Art > > -----Original Message----- > From: Poul-Henning Kamp <[email protected]> > Sent: Sunday, November 29, 2020 11:19 PM > To: Discussion of precise time and frequency measurement > <[email protected]>; Art Sepin <[email protected]> > Subject: Re: [time-nuts] EOL Motorola Oncore Remote Antenna > > -------- > >> It's obvious from the photo that the O-Ring seal failed its purpose >> over its many years of service. Has the unit totally failed or does the > electronic portion still function? > > No, the electronics is stone dead. > > To me it looks more like water ingress through micro-cracks in the > plastic-dome, and the O-ring did its job and kept that water in. > > The microcracks are uniform and seem to follow the molding flow, and that is > probably to be expected in our climate: We have a lot of humid freeze-thaw > cycles. > > I wonder if buffing the radomes with car-wax would help ? > >> I said lucky because I found some GSynQ parts here in an engineering >> storage cabinet that we can send to you at no charge to revive your unit. > Thanks for the offer, but dont bother: I had a spare on hand, and I may > still have third one lying around somewhere. > -- Stephen Tompsett _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
