Re: [time-nuts] worth salvaging ?
paulswedb@gmail.com said:
I have been working with another time-nut to recover austron 2201a GPS
receivers and unfortunately I seem to have come to the conclusion that we
can not get the almanacs to update and will guess this would be the same
issue with these potentially.
Is the problem that they don't get an almanac, or that they get the wrong
answer?
There was a week rollover in one of the main GPS fields several/many years
ago. That ws the first one since GPS started. It made some units give crazy
answers. (I think they were time only, position was OK.)
I think you could get around that with some post-processing. I don't
remember anybody doing that. Some units got new firmware.
--
These are my opinions, not necessarily my employer's. I hate spam.
Hal
Thanks for your comments. Not sure I want to depart from Peters thread to
far. I was aware of several items y2K, the GPS rollover and I seem to recall
a 3rd thing.
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.
But additionally it tends to track for a while and at times a long while at
least 1 sat. But never seems to go to 2-3. Running a garmin so that I can
see the real satellites shows that what the austron wants to track may or
may not be real kind of pot luck.
Email me, or start a separate thread and we can give this back to Peter.
Regards
Paul
WB8TSL
On Fri, Jan 28, 2011 at 11:03 PM, Hal Murray hmurray@megapathdsl.netwrote:
paulswedb@gmail.com said:
I have been working with another time-nut to recover austron 2201a GPS
receivers and unfortunately I seem to have come to the conclusion that we
can not get the almanacs to update and will guess this would be the same
issue with these potentially.
Is the problem that they don't get an almanac, or that they get the wrong
answer?
There was a week rollover in one of the main GPS fields several/many years
ago. That ws the first one since GPS started. It made some units give
crazy
answers. (I think they were time only, position was OK.)
I think you could get around that with some post-processing. I don't
remember anybody doing that. Some units got new firmware.
--
These are my opinions, not necessarily my employer's. I hate spam.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
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@nf6x.net
Web page: http://www.nf6x.net/
GnuPG public key available from my web page.
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@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@nf6x.net
Web page: http://www.nf6x.net/
GnuPG public key available from my web page.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
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@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@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@nf6x.net
Web page: http://www.nf6x.net/
GnuPG public key available from my web page.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
On Sat, Jan 29, 2011 at 10:14 AM, Mark J. Blair nf6x@nf6x.net wrote:
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.
It all depends on the receiver firmware. I remember when the GPS week
rolled over; I was in the process of driving from a conference in
California back to home in British Columbia, with a GPS receiver or
two in the car tracking our progress. We stopped for a meal, powering
the GPS receivers off. When we returned to the car, one of the
receivers (a Garmin) would not re-acquire satellites no matter how
long I gave it. I later figured out that the week rollover had
happened that afternoon, while we were driving, and the first restart
after the rollover failed.
But it apparently wasn't just a case of having to do a cold start to
get a new almanac, because I couldn't get that receiver to work again
myself. In a little while, Garmin released a small utility that you
ran on a PC connected to the GPS via its serial port, and it reset
something that allowed the GPS to do a successful cold start. I
remember an rumour that it simply reset the saved date and time far
enough away that the receiver dumped all its old almanac entries,
forcing it to do a cold start that worked. This suggests that it had
been keeping its pre-rollover almanac data and tried to use it, but
there was a bug in the calculation that resulted in mispredicting what
satellites should be visible where. But that's just a guess - Garmin
never said exactly what was wrong, or what they did to fix it.
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.
Yes. If you offered them for postage cost, you'd probably find a
bunch of takers. You wouldn't even have to unsolder them - let the
recipient do that. It seems a waste to discard a perfectly good OCXO
- it would make a fine upgrade to an inexpensive frequency counter
(many of which just have a bare crystal, not even a TCXO).
Peter was looking at the down converter pixs.
Several comments they are in quite good shape at least these pixs.
The resolution on 2740 and 42 are just at the edge so when you expand
everything you loose the part numbers so if they could be read the frequency
scheme might be reversed out.
I am indeed wondering if the pll arrangement is the same as the austron. 10
Mhz ref up coax First mixer is 1500 Mhz and downconverts to 75.42 MHz first
IF down coax.
You want to scrap these because???
Thanks
Paul.
On Sat, Jan 29, 2011 at 7:03 PM, David Martindale <dave.martindale@gmail.com
wrote:
On Sat, Jan 29, 2011 at 10:14 AM, Mark J. Blair nf6x@nf6x.net wrote:
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.
It all depends on the receiver firmware. I remember when the GPS week
rolled over; I was in the process of driving from a conference in
California back to home in British Columbia, with a GPS receiver or
two in the car tracking our progress. We stopped for a meal, powering
the GPS receivers off. When we returned to the car, one of the
receivers (a Garmin) would not re-acquire satellites no matter how
long I gave it. I later figured out that the week rollover had
happened that afternoon, while we were driving, and the first restart
after the rollover failed.
But it apparently wasn't just a case of having to do a cold start to
get a new almanac, because I couldn't get that receiver to work again
myself. In a little while, Garmin released a small utility that you
ran on a PC connected to the GPS via its serial port, and it reset
something that allowed the GPS to do a successful cold start. I
remember an rumour that it simply reset the saved date and time far
enough away that the receiver dumped all its old almanac entries,
forcing it to do a cold start that worked. This suggests that it had
been keeping its pre-rollover almanac data and tried to use it, but
there was a bug in the calculation that resulted in mispredicting what
satellites should be visible where. But that's just a guess - Garmin
never said exactly what was wrong, or what they did to fix it.
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.
Yes. If you offered them for postage cost, you'd probably find a
bunch of takers. You wouldn't even have to unsolder them - let the
recipient do that. It seems a waste to discard a perfectly good OCXO
- it would make a fine upgrade to an inexpensive frequency counter
(many of which just have a bare crystal, not even a TCXO).
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
You want to scrap these because???
time to thin the 'stuff' herd, i.e. I need the room. There at one time
were over 100 of these things, and maybe 40 recovered
antenna/downconverters. Add each has a 50' or 100' coax cable, a power
supply and they are taking a lot of space.
Just about every antenna/downconverter that lived outside is dead.
Plus I've been offered more for the HP displays then I've
been for the units.
For those curious they came from a company I worked at that is long
dead. They where only interested in a decent 1 PPS
and to replace Spectracom WWVB clocks. Odetics won the bid for 1,000
units and within a few months of being installed
the started to die. 90% where located in FM radio transmitter
buildings, so of which would cost $1,000 via helicopter to get
to in the winter. When they where replaced many of the
Antenna/downcoverters were just left behind. Odetics picked up the
bill to have them all replaced. They were suppose to be destroyed but
being a pack rat, I pulled them all out of the dropbox.
anyway .. I'll part out a few, take the HP LED's and offer them to the
t'nuts list members for the cost of shipping. I'll find out
how much can be shoved in a USPS flat rate box next week.
-pete
On Jan 29, 2011, at 4:03 PM, David Martindale wrote:
It all depends on the receiver firmware. [...]
In a little while, Garmin released a small utility that you
ran on a PC connected to the GPS via its serial port, and it reset
something that allowed the GPS to do a successful cold start. I
remember an rumour that it simply reset the saved date and time far
enough away that the receiver dumped all its old almanac entries,
forcing it to do a cold start that worked.
Ah, yes. If the receiver is too stubborn to give up and do a very cold start, then it may single-mindedly continue searching exactly where the satellites aren't!
--
Mark J. Blair, NF6X nf6x@nf6x.net
Web page: http://www.nf6x.net/
GnuPG public key available from my web page.