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 les...@veenstras.com 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:time-nuts-boun...@lists.febo.com] 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 <p...@phk.freebsd.dk> Sent: Sunday, November 29, 2020 11:19 PM To: Discussion of precise time and frequency measurement <time-nuts@lists.febo.com>; Art Sepin <a...@synergy-gps.com> 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. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.