[time-nuts] 58503A alarm light on

Bob Camp kb8tq at n1k.org
Sun Apr 5 09:03:32 EDT 2015


I for one, got *all* my Z38xx’s from the same sort of Chinese sources as
you did. None of them took more than a month or two to come down to the
point they forecast < 2 us. It took some of them quite a while to get to the 
point that they were in the < 500 ns range (three to six months). 

Unless you have a 10811 version, and either 

a) It’s a true 10811 without the heater jacket 
b) it’s a heater jacket version with a compromised seal


it’s been under water for a while

You should not see horribly long (> 3 months) run-in periods on one of these.

If indeed your sample has gone underwater in a flood, all bets are off.


> On Apr 4, 2015, at 10:13 PM, Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby at kirkbymicrowave.co.uk> wrote:
> On 5 Apr 2015 02:26, "Charles Steinmetz" <csteinmetz at yandex.com> wrote:
>> One expects a safety factor between the minimum spec and typical
> operation.  I'd be concerned if a 58503 was consistently predicting >2uS
> (to me, >2uS means "I may still meet spec, but I'm not as stable as I
> should be").
>> Best regards,
>> Charles
> I gathered from Said and others these oscillators can take a long time to
> reach their best stability - up to a year. How good they are then is just
> luck.
> Given mine was e-waste at some point in Hong Kong,  and has certainly been
> in water, the oscillator has probably had a hard time.
> I have now had two other people email me to say that the alarm light lit on
> their 58503A recently.  One person emailed me 2 hours ago and said it
> happened 2-4 days ago.  Mine was about 5 days ago. And another person said
> "recently", but I don't know how recent that is.
> I am beginning to wonder if the impending leapsecond could be the cause of
> the alarm.
> My antenna location could be improved,  but so can any antenna
> installation. I could push it up so it is a couple of metres clear of the
> garage - currently it is mounted to the side of the garage,  about 500 mm
> above the apex. If I mounted the mast on the garage,  rather than a fence
> post, it would be more in the clear of the garage.  I can't clear my house
> or a neighbours house, but they are both a reasonable distance away.
> Dave
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