[time-nuts] worth salvaging ?

[Pete Lancashire]

I'll keep one or two

here's some pictures of the inside of the down converter

http://petelancashire.com/gallery/main.php?g2_itemId=19822&g2_page=2

for detail, click on the thumbnail, the for full resolution click on the picture
or select the resolution near the upper right



On Sat, Jan 29, 2011 at 1:03 PM, paul swed <paulswedb at gmail.com> wrote:
> On the 2201 I do give it quite a while to get its act together hours. To an
> extent it seems to.
> But the fact that the sat tables which you can view never seem to come into
> alignment with whats going on for real is why I think it may be a lost
> cause.
>
> Back to odetics,
> So it seems at least one works. Peter wouldn't you just keep it around or is
> it sloppy compared to todays Tbolts and such?
> Seems a shame to part'em out if they work unless they really aren't that
> useful.
>
> On Sat, Jan 29, 2011 at 1:14 PM, Mark J. Blair <nf6x at nf6x.net> wrote:
>
>>
>> On Jan 29, 2011, at 6:43 AM, paul swed wrote:
>> > It seems to interpret the almanacs wrong because amazingly enough its
>> > actually does know the correct GPS week which was a shock to me. Unless
>> > thats a simple calculation from the date I might guess.
>>
>> It's the other way around: The GPS week is directly decoded from the GPS
>> signal. If I'm not mistaken, the GPS week roll-over causes a problem of
>> being able to correctly calculate the calendar date from the GPS week. I
>> could be mistaken, but I think that a receiver that doesn't handle the
>> rollover properly but is otherwise in good shape should be able to track
>> satellites and provide a correct position, but the calendar/clock time
>> calculation would be wrong.
>>
>> In a receiver that doesn't have a recent almanac, and particularly in an
>> older receiver that takes a very simple approach to downloading ephemeris
>> and almanac information, initial acquisition could take a long time. It'll
>> need to do a slow full-sky search for its first satellite, and older
>> receivers couldn't do that nearly as quickly as newer ones can. Once it gets
>> that first bird, it may sit there downloading ephemeris and almanac data for
>> at least 12.5 minutes before it does anything else. With an old receiver
>> from that era, give it at least a half hour of good open-sky conditions
>> before you begin to suspect that it's dead.
>>
>>
>> Back to the original topic now: That OCXO may seem mundane by time-nutty
>> standards, but I'd certainly consider it to be worth salvaging. It could
>> have all sorts of applications for radio stuff, portable test equipment, and
>> even time-nutty stuff in an application that wants to be smaller and more
>> portable than a Rb standard or full GPSDO.
>>
>> I also agree that there's likely to be a lot more salvageable stuff on
>> those boards. I see lots of socketed parts. UV-erasable EPROMs are worth
>> saving. Are those Altera parts reprogrammable? If so, then they're worth
>> keeping. Keep any microcontrollers or CPUs that are reprogrammable, or rely
>> on external program memory, or can still be used in spite of fixed internal
>> programming (e.g., an old mask-programmed 8051 can be used as an 8031 by
>> strapping a pin to tell it to ignore its mask ROM and use external program
>> memory).
>>
>> I'd say that any units which track satellites at all after a half hour
>> should be considered for repair, and the rest of the units are goldmines of
>> parts.
>>
>>
>>
>> --
>> Mark J. Blair, NF6X <nf6x at nf6x.net>
>> Web page: http://www.nf6x.net/
>> GnuPG public key available from my web page.
>>
>>
>>
>>
>>
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