Is there any information available about the Quantar GPS reference module -- possible part number PTRN1013A? I could find nothing in my Quantar service manual, on Batlabs, MOL, or anywhere else on the web. Is it possible that this is actually a SP module?
It seems to consist of a GPS module inside a UHSO module chassis and is connected to a partly-populated UHSO main board via a ribbon cable. There is no oven module and relatively few other components mounted on the main board.
At least without a GPS antenna attached, it seems not to generate any reference signal for the Quantar to lock up on when the station is configured for a UHSO. Hence, I am not sure whether it is supposed to supply a reference signal or simply discipline the SCM oscillator to GPS.
I wonder whether anyone has worked with one of these and whether there is any documentation available?
Thanks in advance!
Quantar GPS Reference
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Re: Quantar GPS Reference
My guess is that it probably needs to lock to GPS to begin with, and in the event of GPS LOS, it freewheels as long as it can.
Can you provide photos of the module inside & out? I've never heard of this option before!
Can you provide photos of the module inside & out? I've never heard of this option before!
Re: Quantar GPS Reference
I'll try to post some pictures within a few days.
In the meantime, inside the chassis that normally houses the UHSO, there is a tin shield mounted in the blank space on the main board marked GPS. The board is a UHSO board. There is a 10 pin header on the main board and a ribbon cable leading to a plastic box inside the shielded area. Inside the plastic box is a double-sized board. I think it is simply a GPS receiver. There is a SMA cable that leads to a mini-UHF connector mounted on the front of the chassis, behind the black front panel that says "Reference".
On the main board normally used for the UHSO, there are a small number of support chips. Nothing frequency determining.
All of this makes me think that the purpose is to send GPS timing signals to the SCM. I am wondering what would happen if you put a header on a normal (fully populated) UHSO board and connected the GPS module.
In the meantime, inside the chassis that normally houses the UHSO, there is a tin shield mounted in the blank space on the main board marked GPS. The board is a UHSO board. There is a 10 pin header on the main board and a ribbon cable leading to a plastic box inside the shielded area. Inside the plastic box is a double-sized board. I think it is simply a GPS receiver. There is a SMA cable that leads to a mini-UHF connector mounted on the front of the chassis, behind the black front panel that says "Reference".
On the main board normally used for the UHSO, there are a small number of support chips. Nothing frequency determining.
All of this makes me think that the purpose is to send GPS timing signals to the SCM. I am wondering what would happen if you put a header on a normal (fully populated) UHSO board and connected the GPS module.
Re: Quantar GPS Reference
If it is anything like Nuc or Skytel paging base stations, or the early Nextel stations, it is a OnCore UT board. 1pps (one pulse per second) is used to generate precision 10M reference. The ref can be monitored from the front panel. Some of the gps boards had batteries to maintain the almanac, and some did not. Those with a good battery would reacquire under two minutes after a power failure. Those with a bad battery, or no battery, would require up to a half hour to get a lock. You could not monitor gps status from RSS. You used Hyperterm, or you telneted into the station, and you had to know the service mode commands to view gps status. They require an active antenna. That is, the antenna is a gps target and LNA with current limited 5V supplied up the cable. The LNA supplies about 26db gain at 1575mhz. So, loss is actually important. Too short of cable, or too low loss cable can cause problems similar to a line that is too long. I found plain old RG58 was sometimes the best cable for a 20ft run rather than the 1/2in Heliax speced during the site construction.
Re: Quantar GPS Reference
Bill,
Thanks for the info. That explains a lot. I guess that one of the first things I should do is to replace the battery on mine. I don't have the unit apart right now, but it looked like it had a stack of small cells that probably wouldn't be too hard to change out.
I haven't hooked it up to a GPS antenna yet, so I appreciate the pointers on that. I am guessing that it might have actually come from a NUC rather than a Quantar?
I will try some things, but I may not have time to do it this weekend.
Thanks for the info. That explains a lot. I guess that one of the first things I should do is to replace the battery on mine. I don't have the unit apart right now, but it looked like it had a stack of small cells that probably wouldn't be too hard to change out.
I haven't hooked it up to a GPS antenna yet, so I appreciate the pointers on that. I am guessing that it might have actually come from a NUC rather than a Quantar?
I will try some things, but I may not have time to do it this weekend.
Re: Quantar GPS Reference
Fred - Is this reference module installed where the Quantar receiver would normally be? I can help out getting gps batts and antennas for Mot Oncore series. No problem in that arena. I have become far too familiar with the product line than I probably should.
Re: Quantar GPS Reference
Thanks to Bill pointing me towards the Nucleus line, I found the following on the web:
http://www.braddye.com/nucleus/nucleus.html
I have quoted the information about the reference module below. Note that I believe that the statement about the module using 2 slots refers to the physical size of the module -- i.e. it occupies 2 slots like a UHF or VHF receive occupies 2 slots.
The reference module uses 2 slots that contain either the high stability oscillator (HSO) or the ultra high stability oscillator (UHSO). The HSO/UHSO provides a reference for carrier frequency generation in the Exciter and a clock reference in the station control module. The reference is a 5-MHz signal that goes to the station control module and the Exciter through the backplane.
The GPS receiver is built into the reference module of the station when used. The GPS provides a timing reference (1 PPS) and universal time for base station synchronization. The Global Positioning System (GPS) provides a viable source of Universal Coordinated Time (UCT) and synchronization timing.
The Motorola GPS Receiver is a 6-channel simultaneous tracking receiver that provides a timing pulse once per second in an RS232C interface format. The receiver also outputs real time at an RS232C interface to the station control module. The receiver mounts within the reference module enclosure to receive input power and improve RF immunity.
The antenna is an active microstrip patch powered by the GPS receiver. The antenna housing is a ray dome package that has dimensions of 3.9" (99 mm) diameter x 1" (25 mm) high and weighs just 7.3 ounces (210 grams). The design does not require tower mounting. Motorola has also specially designed its GPS receiver to operate in hostile RF environments and over a wide temperature range from -30° C to +60° C.
From this I gather that the Nuc reference may not actually discipline the reference oscillator? Also, the unit that I have does not contain a HSO or UHSO. It would be interesting to install the GPS in a regular Quantar UHSO and see whether it does things such as automatically set the SCM clock to UTC, etc.
Due to a family commitment, I am probably not going to have time to dig into this further today. I appreciate Bill's offer of help and I will follow-up on it soon.
http://www.braddye.com/nucleus/nucleus.html
I have quoted the information about the reference module below. Note that I believe that the statement about the module using 2 slots refers to the physical size of the module -- i.e. it occupies 2 slots like a UHF or VHF receive occupies 2 slots.
The reference module uses 2 slots that contain either the high stability oscillator (HSO) or the ultra high stability oscillator (UHSO). The HSO/UHSO provides a reference for carrier frequency generation in the Exciter and a clock reference in the station control module. The reference is a 5-MHz signal that goes to the station control module and the Exciter through the backplane.
The GPS receiver is built into the reference module of the station when used. The GPS provides a timing reference (1 PPS) and universal time for base station synchronization. The Global Positioning System (GPS) provides a viable source of Universal Coordinated Time (UCT) and synchronization timing.
The Motorola GPS Receiver is a 6-channel simultaneous tracking receiver that provides a timing pulse once per second in an RS232C interface format. The receiver also outputs real time at an RS232C interface to the station control module. The receiver mounts within the reference module enclosure to receive input power and improve RF immunity.
The antenna is an active microstrip patch powered by the GPS receiver. The antenna housing is a ray dome package that has dimensions of 3.9" (99 mm) diameter x 1" (25 mm) high and weighs just 7.3 ounces (210 grams). The design does not require tower mounting. Motorola has also specially designed its GPS receiver to operate in hostile RF environments and over a wide temperature range from -30° C to +60° C.
From this I gather that the Nuc reference may not actually discipline the reference oscillator? Also, the unit that I have does not contain a HSO or UHSO. It would be interesting to install the GPS in a regular Quantar UHSO and see whether it does things such as automatically set the SCM clock to UTC, etc.
Due to a family commitment, I am probably not going to have time to dig into this further today. I appreciate Bill's offer of help and I will follow-up on it soon.
Re: Quantar GPS Reference
In answer to Bill's question, I don't know where the module is supposed to go. However, it looks like it goes in the second receiver / SAM / UHSO slot. That would be the only place for it.
Re: Quantar GPS Reference
My comment has little to do with the Quantar, and more to do with the MCC5500 console.
I connected the consoles through a GPS timing reference and fed it into the MCC5500, which uses the internal DAP and dual DAP boards for routing GPS data for tithe mulming relevance, as well as for use with the Eventide voice loggers.
I never had any internal GPS boards/connections for the multiple Quantars used, so I have nothing useful to add to this discussion.
All I can add, is that all our GPS timing was external to the entire console dispatch layout.
Voice record/playback also had GPS timing overlayed on the screenshots @ the dispatch locations (four).
I connected the consoles through a GPS timing reference and fed it into the MCC5500, which uses the internal DAP and dual DAP boards for routing GPS data for tithe mulming relevance, as well as for use with the Eventide voice loggers.
I never had any internal GPS boards/connections for the multiple Quantars used, so I have nothing useful to add to this discussion.
All I can add, is that all our GPS timing was external to the entire console dispatch layout.
Voice record/playback also had GPS timing overlayed on the screenshots @ the dispatch locations (four).
Re: Quantar GPS Reference
AEC wrote:My comment has little to do with the Quantar, and more to do with the MCC5500 console.
I connected the consoles through a GPS timing reference and fed it into the MCC5500, which uses the internal DAP and dual DAP boards for routing GPS data for tithe mulming relevance, as well as for use with the Eventide voice loggers.
I never had any internal GPS boards/connections for the multiple Quantars used, so I have nothing useful to add to this discussion.
All I can add, is that all our GPS timing was external to the entire console dispatch layout.
Voice record/playback also had GPS timing overlayed on the screenshots @ the dispatch locations (four).
Not to flame, but yes well I believe we're all familiar with external timing references.
WAW, did you come up with anything?
Re: Quantar GPS Reference
The gps 1pps is used by the reference osc to generate 5mhz. Therefore, this is a gps disciplined oscillator, and qualifies as a UHSO.
Re: Quantar GPS Reference
Well, I haven't had time to take the pictures yet.
I did try connecting it to the GPS antenna I use for my 10 MHz house standard. After leaving the Quantar on for several hours, I could not see that it was supplying anything usable to the station. No oscillator, UTC time, etc.
Since it appears that the output is RS-232, I guess the next thing to do is to try to break that out to see whether any data is being output.
The more I look at this, the more I think that it was designed just to supply 1 pps and not to discipline the station reference oscillator. I am not even sure that it would actually supply 1 pps in a format the Quantar would recognize.
I did try connecting it to the GPS antenna I use for my 10 MHz house standard. After leaving the Quantar on for several hours, I could not see that it was supplying anything usable to the station. No oscillator, UTC time, etc.
Since it appears that the output is RS-232, I guess the next thing to do is to try to break that out to see whether any data is being output.
The more I look at this, the more I think that it was designed just to supply 1 pps and not to discipline the station reference oscillator. I am not even sure that it would actually supply 1 pps in a format the Quantar would recognize.
Re: Quantar GPS Reference
You could have a bad gps board. Those 6 channel VP boards are notorious for no acquire, permanent bad almanac, not applying leap seconds, insane navigation, and noisy 1pps. The no acquire is self explanatory. Poor navigation and not adding leap seconds won't matter to an oscillator, but a bad almanac and noisy 1pps will. A bad almanac will prevent the board from setting it's health bit, and thus appear out of lock. A 1pps with lots of artifact will act like jitter forcing the vco in the synthesizer to stay out of lock.
Re: Quantar GPS Reference
Bill,
Do you happen to have the pinout for the GPS board? While I have the real Quantar service manual that covers the UHSO board (which this unit uses) and could probably figure out which pins supply power, it would be helpful if I could just connect the board directly to a computer running a terminal program and see whether there is any output.
Am I going to have to do any level conversion on the output? I got the impression from reading the Nucleus stuff that the GPS board outputs RS-232. Of course, the conversion could be done at another point.
If the board proves bad, is there a more recent one I could easily drop into the chassis?
If none of this works out, I may stick a Soekris net5501 and audio board in the module chassis. Then, I could play with some of the things like they are doing over at http://www.wb6ece.org/ There is adequate room and the power for the computer could be obtained from the Quantar bus by retaining the card the GPS board is mounted on. Of course, I'd still need to use an external reference.
Thanks for all the help and info
Fred
Do you happen to have the pinout for the GPS board? While I have the real Quantar service manual that covers the UHSO board (which this unit uses) and could probably figure out which pins supply power, it would be helpful if I could just connect the board directly to a computer running a terminal program and see whether there is any output.
Am I going to have to do any level conversion on the output? I got the impression from reading the Nucleus stuff that the GPS board outputs RS-232. Of course, the conversion could be done at another point.
If the board proves bad, is there a more recent one I could easily drop into the chassis?
If none of this works out, I may stick a Soekris net5501 and audio board in the module chassis. Then, I could play with some of the things like they are doing over at http://www.wb6ece.org/ There is adequate room and the power for the computer could be obtained from the Quantar bus by retaining the card the GPS board is mounted on. Of course, I'd still need to use an external reference.
Thanks for all the help and info
Fred
Re: Quantar GPS Reference
Fred - there are a number of resources on the web regarding Oncore gps boards. It is a well hacked product.
http://www.google.com/search?client=ope ... 8&oe=utf-8
You will have to determine by the photos you find on the web what vintage of gps board you have. It could be an XT, a VP, a VP+, a GT, or if new enough a UT which is about the time Mot sold their interest in gps to SiRF who came out with a completely different form factor based on different chipsets. Yes, the naked board has TTL interface that requires support chips to make RS232. If the gps device you have comes in a carrier that has the interface built in, you're halfway there. If it is daughter board mounted to the ref module board, you will have to roll your own interface which you will find plenty of in the Google search above.
http://www.google.com/search?client=ope ... 8&oe=utf-8
You will have to determine by the photos you find on the web what vintage of gps board you have. It could be an XT, a VP, a VP+, a GT, or if new enough a UT which is about the time Mot sold their interest in gps to SiRF who came out with a completely different form factor based on different chipsets. Yes, the naked board has TTL interface that requires support chips to make RS232. If the gps device you have comes in a carrier that has the interface built in, you're halfway there. If it is daughter board mounted to the ref module board, you will have to roll your own interface which you will find plenty of in the Google search above.