Has anyone used the Rockwell gps boards to lock a 10MHz oscillator? If so, where can I get one cheep?

--
Yours truly,

Chuck

WA3IAC

FN20la

http://www.qsl.net/wa3iac/

Chuck S. wrote:

Has anyone used the Rockwell gps boards to
lock a 10MHz oscillator? If so, where can I get
one cheep?

Define "cheap".

Have you tried EBay? I've picked up a number
of OEM GPS receivers there, both Motorola
OnCore and Rockwell Jupiter units.

Laura Halliday VE7LDH "Yeah but no but
Grid: CN89mg yeah but no but..."
ICBM: 49 16.05 N 122 56.92 W - V. Pollard

On Tue, 03 Jan 2006 00:48:45 GMT, "Chuck S." wrote:

Has anyone used the Rockwell gps boards to lock a 10MHz oscillator?

Yep

If so, where can I get one cheep?

Found mine on ebay.

Thanks, I did fine some on eBay. Cheep is anything under $50!! hahahah


"budgie" wrote in message
...
On Tue, 03 Jan 2006 00:48:45 GMT, "Chuck S."
wrote:

Has anyone used the Rockwell gps boards to lock a 10MHz oscillator?

Yep

If so, where can I get one cheep?

Found mine on ebay.

OK, one more question, do you need the RS-232 port if you only want to lock
a vcxo to the 10kHz? My guess is no, just +5 volts and ground, and take the
10kHz from pin 20 of the connector.


"Chuck S." wrote in message
news:0hZuf.3732$QI6.1436@trnddc07...
Thanks, I did fine some on eBay. Cheep is anything under $50!! hahahah


"budgie" wrote in message
...
On Tue, 03 Jan 2006 00:48:45 GMT, "Chuck S."
wrote:

Has anyone used the Rockwell gps boards to lock a 10MHz oscillator?

Yep

If so, where can I get one cheep?

Found mine on ebay.

On Thu, 05 Jan 2006 00:02:17 GMT, "Chuck S." wrote:

OK, one more question, do you need the RS-232 port if you only want to lock
a vcxo to the 10kHz? My guess is no, just +5 volts and ground, and take the
10kHz from pin 20 of the connector.

No you don't need to concern yourself with the data port (*)(**) for a frequency
reference. Just make sure you have the appropriate 0v/5v on the appropriate
lines as per the data sheet to get the bootup mode correct.

* Without parsing the $GPRMC sentence you can't tell if you have a valid fix.
And that is the ONLY sure way to know your 10kHz is actually locked to the sat
source(s) and not derived from the rx oscillator free-running. It's pity one of
those N/C pins doesn't have a "valid" flag on it - would save the need for a
downstream processor.

** I presume you are (also) talking Rockwell/Conexant Jupiter board.

Chuck S. wrote:
OK, one more question, do you need the RS-232 port if you only want to lock
a vcxo to the 10kHz? My guess is no, just +5 volts and ground, and take the
10kHz from pin 20 of the connector.

I have used the older Rockwell GPS stuff and they seem to need to have a
recent almanac transferred to them before they will get a fix. Rockwell
used to distribute a freebie software package that would help you deal
with all the setup stuff. It was called something like Lab_10 or Lab_X
or somesuch. The newer stuff may need less handholding.

Good Luck,
Bob

On Thu, 05 Jan 2006 03:12:07 GMT, MetalHead
wrote:

Chuck S. wrote:
OK, one more question, do you need the RS-232 port if you only want to lock
a vcxo to the 10kHz? My guess is no, just +5 volts and ground, and take the
10kHz from pin 20 of the connector.

I have used the older Rockwell GPS stuff and they seem to need to have a
recent almanac transferred to them before they will get a fix. Rockwell
used to distribute a freebie software package that would help you deal
with all the setup stuff. It was called something like Lab_10 or Lab_X
or somesuch. The newer stuff may need less handholding.

That's an interesting observation, Bob. I was watching the NMEA output from
power-up on the Jupiter I am using doing a "frozen start" out of the box without
an antenna. One sentence showed it checking each sat in turn. When it finds
one (which it obviously doesn't do with no ant) it assigns a Rx channel# to it.

When I finished play mode on the pooter end and connected an ant, it went
through each bird in turn, about one per second. So within a minute it had
acquired a set of birds and began processing. As I am using no form of backup,
the Jupiter starts from ROM each time and does a similar "frozen start" i,e,
factory almanac). It consistently achieves a full fix in under 3 minutes.

Thanks budgie, I was talking about the Jupiter bd. Another thought was will
it work without an antenna? I guess it will. I will be using it outside on
hill tops so should not have a problem a set of birds to lock on. I see an
output on pin 19 that is mark Epps that may be use to show a lock condition.


"budgie" wrote in message
...
On Thu, 05 Jan 2006 03:12:07 GMT, MetalHead
wrote:

Chuck S. wrote:
OK, one more question, do you need the RS-232 port if you only want to
lock
a vcxo to the 10kHz? My guess is no, just +5 volts and ground, and take
the
10kHz from pin 20 of the connector.

I have used the older Rockwell GPS stuff and they seem to need to have a
recent almanac transferred to them before they will get a fix. Rockwell
used to distribute a freebie software package that would help you deal
with all the setup stuff. It was called something like Lab_10 or Lab_X
or somesuch. The newer stuff may need less handholding.

That's an interesting observation, Bob. I was watching the NMEA output
from
power-up on the Jupiter I am using doing a "frozen start" out of the box
without
an antenna. One sentence showed it checking each sat in turn. When it
finds
one (which it obviously doesn't do with no ant) it assigns a Rx channel#
to it.

When I finished play mode on the pooter end and connected an ant, it went
through each bird in turn, about one per second. So within a minute it
had
acquired a set of birds and began processing. As I am using no form of
backup,
the Jupiter starts from ROM each time and does a similar "frozen start"
i,e,
factory almanac). It consistently achieves a full fix in under 3 minutes.

budgie wrote:
On Thu, 05 Jan 2006 03:12:07 GMT, MetalHead
wrote:


Chuck S. wrote:

OK, one more question, do you need the RS-232 port if you only want to lock
a vcxo to the 10kHz? My guess is no, just +5 volts and ground, and take the
10kHz from pin 20 of the connector.

I have used the older Rockwell GPS stuff and they seem to need to have a
recent almanac transferred to them before they will get a fix. Rockwell
used to distribute a freebie software package that would help you deal
with all the setup stuff. It was called something like Lab_10 or Lab_X
or somesuch. The newer stuff may need less handholding.


That's an interesting observation, Bob. I was watching the NMEA output from
power-up on the Jupiter I am using doing a "frozen start" out of the box without
an antenna. One sentence showed it checking each sat in turn. When it finds
one (which it obviously doesn't do with no ant) it assigns a Rx channel# to it.

When I finished play mode on the pooter end and connected an ant, it went
through each bird in turn, about one per second. So within a minute it had
acquired a set of birds and began processing. As I am using no form of backup,
the Jupiter starts from ROM each time and does a similar "frozen start" i,e,
factory almanac). It consistently achieves a full fix in under 3 minutes.

This surprised me also. As I mentioned earlier, these two system that
this showed up on were very old, 5 channel receivers.

Sitting outside, with a clear view of the sky, the receivers would
search through one sat at a time and find one occasionally, but they
would lose them after several minutes. After a couple of hours, they had
not acquired and held enough SV's to get a fix at any time.

I loaded up an almanac through the tool and either receiver would get a
fix within a few minutes and hold it for the half hour that I left them
to run.

I am assuming that these receivers were running out of ROM as well. Some
GPS systems put an almanac in ROM to improve the cold start fix time,
but I don't know if these are among them.

As for the original poster's other question about needing an antenna, I
would say that unless there is one on the Jupiter board, then yes.

Bob