[time-nuts] GPS failure...

Magnus Danielson cfmd at bredband.net
Tue Feb 7 17:22:03 EST 2006


From: "Arnold Tibus" <Arnold.Tibus at gmx.de>
Subject: Re: [time-nuts] GPS failure...
Date: Tue, 7 Feb 2006 22:47:59 +0100 (MET)
Message-ID: <4866.1139348879 at www092.gmx.net>

> Hello Magnus,

Hi Arnold,

> was there no small hole on the lower side, underneath, 
> was it blocked by the little spider?

No, the hole I think was intended for that purpose was hidden under the label
giving away what manufacter and model-number it is.

> Offshore working with meteorologic sensors and electronics, 
> I experienced personally that it is not a very good idea to build 
> antennas or other electronic devices into hermetic cases 
> without a breating hole in it (well protected against rain and 
> drops of water, possibly contain a filter device) unless the case 
> is not pressure cycling proof, including cables and connectors. 

I think this device had one designed. But I suspect it was put out of action
by the label. :P

> Due to temperature and air pressure changes, 
> these devices are breathing air with humidity via the connectors, 
> coaxial and other cables, which in colder phases is condensing 
> and remaining inside, that way filling up the box, drop per drop.

Which is what I suspect this baby died off.

> The 2nd way is to build a real pressure proof box with hermetic 
> feed through connectors (glass or ceramic insert, O-ring sealed), 
> capable to withstand more than 1 meter of water immersion.

Well, yes. Thing is, I'm not building them, I am just trying to use one or two
antennas.

> Good luck and have fun,
> 
> Arnold, DK2WT

Thanks for the insight. It is along the lines of what I have a gut-feeling of,
but it is good to get confirmation.

Cheers,
Magnus




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