"Kasper Pedersen" <[email protected]> wrote in message
news:[email protected]...
[]
> The top dome has two onion rings, the outer being 1mm larger than the
> base. The base is a plastic cup, with a groove in the edge, and a rubber
> overmold. The top's inner ring fits in the groove, the top's outer ring
> goes on the outside of the cup. During manufacture a weak, silicone
> rubber like adhesive is put in the groove, and the top put on. It is
> held in place with three clips; There's a 'stirrup' in the base, and a
> hook in the top. Compressed air applied to the breather hole on the
> bottom loosened the glue. One clip is right next to the thickest bulge
> in the strain relief. A screwdriver forced under the top there, and with
> some force applied, it yields. The two other clips then come loose with
> some wiggling.
Most helpful, Kasper, although I hope I don't need it. I have made a
note.
> The -5V on the serial output line is as it should be. I expected it to
> be RS232-polarity 5V CMOS, but it does have a proper RS232 transceiver
> with charge pumps.
Inconsistent with the technical specification, which says 0..+5V, but
consistent with what I measured.
> The PPS output of 3.10 is a lot better than the 1us spec. Typical wobble
> for the decapsulated one sitting indoors is +/-50 ns when observed for
> some minutes. It is 60ns+/-50ns slow compared to where I think it should
> be (At the end of 5m cable it is 85+/-50ns slow).
>
> /Kasper Pedersen
That's most encouraging - although if I get within a few tens of
microseconds I'm happy!
I don't know now what firmware version mine was, but the recent updates
have a history:
Changes made from version 3.10 to 3.20:
* Modified proprietary binary output data format to fix incorrect
date/time calculation on some Garmin marine products.
Changes made from version 3.00 to 3.10:
* Improved robustness of internal error handling.
I didn't see any updates for the older GPS18 LVC.
Cheers,
David
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