Trimble 65256 5V 10mhz As fitted in Trimble gpsdo and some bg7tbl,output level  - Page 1
Forum section: electronics / projects

author: davebb
author_rank: Frequent Contributor
timestamp: December 26, 2015, 08:57:24 am
content: Hi anyone using the Trimble 65256 ocxo as fittedin some ex eqt GPSDO,what is your voltage 10mhz output level into 50ohmor if you do have the cheap trimble 10mhz gpsdo fitted with the Trimble 65256 ocxo what is your output level from the gpsdo the one I have is very low only 300mv out off the gpsdo,I have talked to TheSteve and his is 2-3v from his gpsdo board but his Trimble ocxo is a 63090 unitI have talked to edpalmer42 and his Trimble 65256 in his gpsdo output was some times 400mv and some times 300mv out, so are our Trimble 65256 not putting out the correct output? as we can not fined any data sheets for this OCXOThanks Dave 2E0DMB

author: TheSteve
author_rank: Unknown
timestamp: December 26, 2015, 09:16:34 am
content: Just to confirm my GPSDO with the 63090 OCXO outputs 3 volts peak to peak into a high impedance and 1.5 volts peak to peak into 50 ohms. This is from the 10 MHz output connector - I have not measured the level direct from the OCXO itself. It can't be a direct connection as the output is switched on and off.

author: davebb
author_rank: Frequent Contributor
timestamp: December 26, 2015, 10:49:19 am
content: Thanks SteveAlso steve can you please tell me what is the voltage that is leaking before your output s switched onas i wonder if the output from the ocxo is then bufferd?also i am not getting anything out of my 1pps socket,i am not planing on using that anywaythe board does say that is actveThanks Dave57964-05 serial number 84612705 firmware ver 1.0.0.2-01 W-CDMA mode-------------------------------------------------------------------------------Reference Status __________________________ Reference Outputs _______________XX Ref 8KHz 0: XX Ref 8KHz 1:  TFOM 2 FFOM 0XX Ref 8KHz 2:  UCCM A StatusXX Ref 8KHz 3: >> GPS: [phase:-2.0E-09]ACQUISITION ...................................................[GPS 1PPS Valid]Tracking: 6 ____ Not Tracking: 4 ________ Time ____________________________PRN El Az C/N PRN El Az GPS 09:54:50 26 Dec 201523 27 180 35 32 57 661 67 112 43 31 11 79 ANT DLY 0 ns3 82 248 40 14 11 35 Position ________________________11 47 143 37 28 11 254 MODE Hold19 56 270 4117 44 295 34 LAT N 50:51:38.251LON W 0:56:0.457HGT +60.54 m (MSL)ELEV MASK 5 deg-------------------------------------------------------------------------------Command completeUCCM >

author: davebb
author_rank: Frequent Contributor
timestamp: December 26, 2015, 10:55:56 am
content: also with the trimble ocxo in the gpsdo the output is loaded to 50ohmsif anyone knows were on the board the 10mhz does get switched on please let me know,Thanks Dave 2E0DMB

author: davebb
author_rank: Frequent Contributor
timestamp: December 26, 2015, 01:17:51 pm
content: I have got it workingthe output comes on when lock like it should and now i can use the MACT switch to enable 10mhz out before lock the output into the scope set on 50ohm is 1.34v and with scope set on 1meg the voltage ut of the gpsdo is 2.6v,the 1pps out still is not working,it may be on the ribbon connector,but i dont need this,The Problam was on c137 on the right hand side there was a blob of solder going to the track on R206c137 connects the AD8027 Low Distortion, High Speed Rail-to-Rail Input/Output Amplifier between the ocxo and the output socket,it looks like the mod/bodge was done to lower the output level of this trimble gpsdoThank you all for your Help and infoThanks Dave 2E0DMB

author: davebb
author_rank: Frequent Contributor
timestamp: December 26, 2015, 01:39:36 pm
content: this is a photo,may help othersDave 2E0DMB

author: Deathwish
author_rank: Unknown
timestamp: December 26, 2015, 05:25:37 pm
content: Can anyone tell me what the pin out is on the ribbon cable connector ?.

author: TheSteve
author_rank: Unknown
timestamp: December 26, 2015, 05:28:12 pm
content: Glad you got it working. When looking at the PPS output remember the pulse is very short. It can be tough to see with a scope. A single shot trigger will usually find it pretty quick.

author: TiN
author_rank: Super Contributor
timestamp: December 26, 2015, 05:28:28 pm
content: Mine is somewhere in the post still, I'll post my findings when to receive.Never used any GPSDO before, is it as simple as powering it on and hooking GPS antenna to input to get 10MHz from this thingy?

author: TheSteve
author_rank: Unknown
timestamp: December 26, 2015, 06:00:33 pm
content: Quote from: TiN on December 26, 2015, 05:28:28 pmYes it is - you do need to wait for it to lock of course.

author: davebb
author_rank: Frequent Contributor
timestamp: December 26, 2015, 06:41:30 pm
content: Thanks Steve,The first time you plug it in it will take a long time but once it knows were it is ,it will be faster

author: davebb
author_rank: Frequent Contributor
timestamp: December 26, 2015, 07:20:38 pm
content: Hi TinMine took 2 weeks to the uk and it was very well packed,dont try and connect it up to 12v,i use 6v and the ocxo gets 5v from the ldo reg,the first diode is a over voltage clamping diode so it has got good voltage protection,Dave 2E0DMB

author: TheSteve
author_rank: Unknown
timestamp: December 26, 2015, 07:29:30 pm
content: Did you find the 1 PPS pulse?

author: davebb
author_rank: Frequent Contributor
timestamp: December 26, 2015, 07:47:49 pm
content: Hi steveno I need to have another look,i can see it on the ublox 6-7 gps units,I don't think it is there,my counter does not see it.thanks Dave

author: davebb
author_rank: Frequent Contributor
timestamp: December 26, 2015, 08:00:15 pm
content: I now need to get my antenna outside,the tracking I have posted is with the antenna indoors top floor and it was raining,it does sometimes go to tracking 1 sat and still locked,anyone know how to connect up a ublox gps module.Dave 2E0DMB

author: TheSteve
author_rank: Unknown
timestamp: December 26, 2015, 10:56:22 pm
content: Here are two shots of the PPS output from my Trimble to give you an idea of what it should look like.

author: davebb
author_rank: Frequent Contributor
timestamp: December 27, 2015, 08:48:56 am
content: Hi SteveNo output from the 1pps connecter,like I say I can see it very easy on a u-blox gps,Thanks Dave

author: TheSteve
author_rank: Unknown
timestamp: December 27, 2015, 09:13:26 am
content: I wonder if it was disabled in firmware - if you give the command OUTput:TP:SELection? I assume you get PP1S ?

author: davebb
author_rank: Frequent Contributor
timestamp: December 27, 2015, 09:59:20 am
content: Hi STEVEYes it doesThanks Dave

author: sp2iqw
author_rank: Newbie
timestamp: December 27, 2015, 10:03:46 am
content: Hi Steve,I think that most probably your GPSDO board didn't finished selfsurvay mode which is signalized by fast flashing green LED. My board 57964-05 sends 10us pulse on the connector in tracking mode.The full operating mode requires at least 10-15mins to get a PPS output with good GPS signal (better forget about using indoor or window located antenna).You can check the mode using terminal connected to J5 pins (57600,N,8,1) typing one of these commands:*IDN?SYST:STAT?Unfortunately still many commands are not known especially DIAG (don't work). Any suggestions ?BTW,"Trimble 65256" refers only to the on-board (5V) OCXO. The whole board has a Trimble Part Number (TPN) is 57964-05.Unfortunately as it is an OEM product only marginal information can be found on the Internet.

author: davebb
author_rank: Frequent Contributor
timestamp: December 27, 2015, 10:43:19 am
content: Hi sp2iqwits me that i am not getting 1pps ot off the socket on the board, not stevethe board did finish doing the selfsurvey whe i first switch it on here in the uk,why i posted ,Trimble 65256 is becose that is the ocxo i have fitted on my Trimble 57963-B boardi had very low rf level out of the 10mhz connecter 300mv, That i now have fixed,the thing that is still not coming from the other output socket is the 1pps,but as you can see from my UCCM >SYSTem:STATus?it is working on the board,Thanks Dave 2E0DMBUCCM >SYSTem:STATus?-------------------------------------------------------------------------------57964-05 serial number 84612705 firmware ver 1.0.0.2-01 W-CDMA mode-------------------------------------------------------------------------------Reference Status __________________________ Reference Outputs _______________XX Ref 8KHz 0: XX Ref 8KHz 1:  TFOM 2 FFOM 0XX Ref 8KHz 2:  UCCM A StatusXX Ref 8KHz 3: >> GPS: [phase:-5.5E-08]ACQUISITION ...................................................[GPS 1PPS Valid]Tracking: 6 ____ Not Tracking: 6 ________ Time ____________________________PRN El Az C/N PRN El Az GPS 06:47:31 27 Dec 20158 84 230 42 32 26 19210 47 63 43 28 14 325 ANT DLY 0 ns22 59 90 42 11 43 274 Position ________________________27 55 133 38 30 6 291 MODE Hold18 18 47 38 16 5 1771 30 260 34 14 15 107 LAT N 50:51:38.251LON W 0:56:0.457HGT +60.54 m (MSL)

author: davebb
author_rank: Frequent Contributor
timestamp: December 27, 2015, 11:00:23 am
content: Hi sp2iqwTheSteve gave me this listThis is the command to change the elevation mask - GPSystem:SATellite:TRACking:EMANgle <degrees>Beware it does not survive a power cycle.The unit does output very weak(leakage) 10 MHz when powered on but the full strength 10 MHz is only enabled once it is locked to GPS.You can force the 10 MHz on instantly by pressing the Mact button or using the command: DIAGnostic:OUTPut ONIf you hit the question mark and then press enter or type HELP it will give you all of the possible commands.Here is a list of them:UCCM >?*IDN?ALARm:HARDware?ALARm:OPERation?DIAGnostic:OUTPut ON|OFFOUTPut:REFerence?OUTPut:ACTive:ENABleOUTPut:ACTive:DISableOUTPut:ACTive:HOLDover:DURation:THReshold <seconds>OUTPut:ACTive:HOLDover:DURation:THReshold?OUTPut:INACTiveOUTPut:INACTive?OUTPut:STATe?SYNChronization:HOLDover:DURation:STATus:THReshold <seconds>SYSTem:PRESetSYNChronization:TFOMerit?LED:GPSLock?SYNChronization:FFOMerit?GPS:POSition N or S,<deg>,<min>,<sec>,E or W,<deg>,<min>,<sec>,<height>GPS:POSition?GPS:POSition:HOLD:LAST?GPS:REFerence:ADELay <numeric value>GPS:REFerence:ADELay?GPS:SATellite:TRACking:COUNt?GPS:SATellite:TRACking?DIAGnostic:ROSCillator:EFControl:RELative?SYNChronization:TINTerval?DIAGnostic:LOG:READ:ALL?DIAGnostic:LOG:CLEarSYSTem:PONOUTPut:MODE?SYSTem:STATus?SYSTem:COMMunication:SERial1:BAUD 9600|19200|38400|57600SYSTem:COMMunication:SERial1:BAUD?SYSTem:COMMunication:SERial1:PRESetSYSTem:COMMunication:SERial2:BAUD 9600|19200|38400|57600SYSTem:COMMunication:SERial2:BAUD?SYSTem:COMMunication:SERial2:PRESetOUTPut:STANby:THReshold <seconds>changeSNSYNChronization:REFerence:ENABLE LINK|GPSSYNChronization:REFerence:DISABLE LINK|GPSSYNChronization:REFerence:ENABLE?STATusPOSSTATusTOD EN|DITIME:STRing?REFerence:TYPE GPS|LINKREFerence:TYPE?PULLINRANGE 0|1|2|...|254|255PULLINRNAGE?DIAGnostic:LOOP?DIAGnostic:ROSCillator:EFControl:DATA GPS|<value>DIAGnostic:ROSCillator:EFControl:DATA?OUTut:TP:SELection PP1S|PP2SOUTut:TP:SELection?GPSystem:SATellite:TRACking:EMANgle <degrees>GPSystem:SATellite:TRACking:EMANgle?DIAGnostic:TCODe:STATus:AMASkDIAGnostic:TCODe:STATus:OMASkDIAGnostic:TCODe:ERRor:AMASkDIAGnostic:TCODe:ERRor:OMASkDIAGnostic:HOLDover:DELayDIAGnostic:HOLDover:DELay?GPS:SATellite:TRACking:IGNore <PRN>, ...,<PRN>GPS:SATellite:TRACking:IGNore?GPS:SATellite:TRACking:INCLude <PRN>, ...,<PRN>GPS:SATellite:TRACking:INCLude?GPS:SATellite:TRACking:<select>:ALL? or HELPCommand completeDave 2E0DMB

author: TheSteve
author_rank: Unknown
timestamp: December 28, 2015, 05:04:02 am
content: Just to compare here is the output from my module. It looks like mine might be a newer rev:UCCM >SYSTem:STATus?-------------------------------------------------------------------------------57964-15 serial number 86972377 firmware ver 3.0.0.11-01LINK mode-------------------------------------------------------------------------------Reference Status __________________________ Reference Outputs _______________XX Ref 8KHz 0: XX Ref 8KHz 1:  TFOM 2 FFOM 0XX Ref 8KHz 2:  UCCM A StatusXX Ref 8KHz 3: >> GPS: [phase:+4.8E-08]ACQUISITION ...................................................[GPS 1PPS Valid]Tracking: 8 ____ Not Tracking: 0 ________ Time ____________________________PRN El Az C/N PRN El Az GPS 05:00:17 28 Dec 201530 79 316 485 20 267 38 ANT DLY 0 ns7 63 88 40 Position ________________________27 19 40 42 MODE Hold8 39 68 4513 29 311 49 LAT N 49:xx:15.89828 49 228 44 LON W 122:xx:25.7869 23 161 39 HGT +11.64 m (MSL)ELEV MASK 15 deg-------------------------------------------------------------------------------Command completeUCCM >

author: davebb
author_rank: Frequent Contributor
timestamp: December 28, 2015, 06:33:22 am
content: Yes Steve it does and they are in different modes mine is in w-cdmaThat might be why mine had very low outputThanks Dave

author: TheSteve
author_rank: Unknown
timestamp: December 28, 2015, 07:11:14 am
content: I noticed that.Does yours produce the same output with these commands?REFerence:TYPE GPS|LINKREFerence:TYPE?

author: davebb
author_rank: Frequent Contributor
timestamp: December 28, 2015, 08:26:43 am
content: Hi SteveUCCM >REFerence:TYPE?GPSUCCM >REFerence:TYPE GPS|LINKParameter errornothing changesThanks DAVE

author: TheSteve
author_rank: Unknown
timestamp: December 28, 2015, 09:57:24 am
content: Ahh, sorry, I was wondering if your module has the same two options - GPS and LINK or does it have GPS and W-CDMA.

author: davebb
author_rank: Frequent Contributor
timestamp: December 28, 2015, 10:47:19 am
content: Hi SteveDo you think my one could have used the 3GNetwork if Gps was lostThanks Dave

author: TheSteve
author_rank: Unknown
timestamp: December 28, 2015, 08:39:34 pm
content: Quote from: davebb on December 28, 2015, 10:47:19 amWell that would be a little strange, but anything is possible. I know back in the day of paging the transmitters were all synchronized by GPS with a fall back to "link" which was a fixed delay based on link data the controller received via phone line/satellite/radio link etc.

author: davebb
author_rank: Frequent Contributor
timestamp: December 28, 2015, 09:23:35 pm
content: OK it is working very well,I have just orded a nice cheap trimming ant 30dbm tallysman TW3030 to fit outsideThanks Dave

author: davebb
author_rank: Frequent Contributor
timestamp: December 29, 2015, 11:47:33 am
content: Hi I have just wired a DC-DC and set to 6V with 13v in When gpsdo is switched on worming 900ma,when settled 440ma,The main thing is I have not got to finned a 6v psu,this dc-dc can take up to 32v,http://www.ebay.co.uk/itm/272037027884?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AITDAVE 2E0DMB

author: Tin Whiskers
author_rank: Newbie
timestamp: January 01, 2016, 01:43:50 am
content: Hi, I purchased one of these Trimble units, however the receiver is faulty and no birds are tracked. Otherwise it appears fine! It looks like the receiver has taken a physical hit. There appears to be a crack in a capacitor and another component appears broken and missing from its pads. The position of the missing component is indicated in the attached photo.I would greatly appreciate it if someone could check their Trimble board and let me know what the missing component type/value should be, so I can replace it.Peter

author: edpalmer42
author_rank: Super Contributor
timestamp: January 01, 2016, 08:09:44 am
content: The missing component is an inductor. Note that it's actually labelled as L7. The L is wrapped around the white box that surrounds the inductor. It's about 4 turns of wire on a form that's about the same size as the capacitors on either side of it. The form appears to be plastic so you should be able to replace it with a simple coil of wire. Wrap it around the smallest steel pin you can find and then remove the pin.A missing inductor and no satellites makes me wonder if the DC feed to the antenna has been cut. Is there 5V or maybe 3V3 on the center of J2? If it's missing, you could use a satellite splitter with power-passing to inject the DC towards the antenna.Ed

author: davebb
author_rank: Frequent Contributor
timestamp: January 01, 2016, 08:17:04 am
content: Hi tinThe component you are missing is an inductor i dont know the value it probly there for the ant voltageGood luck Dave

author: davebb
author_rank: Frequent Contributor
timestamp: January 01, 2016, 08:23:55 am
content: Hi Ed how did you get on with the info I posted you about what I found reducing the output level of the unit?Dave

author: Tin Whiskers
author_rank: Newbie
timestamp: January 01, 2016, 12:03:31 pm
content: Hi Ed & Dave, Thanks for the info, guys. While a very sensible thought Ed, the antenna voltage and current were actually provided and sensed correctly, so L7 is not involved in this. I decided that the inductor as described could be replaced by a short circuit (bearing in mind the pcb circuit trace inductance and my soldering skills). I also repaired the cracked capacitor.Soon 11 birds at high signal strength were being tracked and the Trimble was in full flight. I think when you get these untested GPSDOs from China you should regard them as a kit of parts.Peter

author: davebb
author_rank: Frequent Contributor
timestamp: January 01, 2016, 12:45:57 pm
content: Hi Peter glad you have it running,I will have to get a antenna outsideDave

author: davebb
author_rank: Frequent Contributor
timestamp: January 01, 2016, 01:44:48 pm
content: How many satellite's are needed for a GPSDO to work correctlyThanks Dave 2E0DMB

author: edpalmer42
author_rank: Super Contributor
timestamp: January 01, 2016, 07:26:43 pm
content: Quote from: davebb on January 01, 2016, 08:23:55 amHi Dave,What with preparing for Christmas and New Year, guests, presents, etc., I haven't got anything powered up yet. I have two of the Trimble GPSDOs, both with the 65236 oscillator. Both have the solder bodge you mentioned. Once I get them hooked up, I'll see if I can duplicate your results with the output level. I should be able to get to it within the next few days.Ed

author: davebb
author_rank: Frequent Contributor
timestamp: January 01, 2016, 08:11:39 pm
content: Hi EdYes it will be good to knowHave a good new yearThanks Dave

author: Tin Whiskers
author_rank: Newbie
timestamp: January 02, 2016, 12:57:02 am
content: Hi Dave, Yes, if you want the best GPS performance a well positioned outdoor antenna is almost essential. You need to track as many birds as possible high in the sky - but certainly at least four. Of course, you may not be able to have an outdoor antenna, so you do the best you can but performance will suffer.Peter

author: Deathwish
author_rank: Unknown
timestamp: January 02, 2016, 01:23:43 am
content: I have 2 antennas on mine, weirdly the little car type puck picks up 10 birds and locks from sitting inside the window, but the large marine antenna in its housing only pics up 2-3 and is rather a let down.

author: TheSteve
author_rank: Unknown
timestamp: January 02, 2016, 01:26:09 am
content: Quote from: Deathwish on January 02, 2016, 01:23:43 amI would say the larger antenna is defective or possibly needs 12 volts instead of the more common 5.

author: Deathwish
author_rank: Unknown
timestamp: January 02, 2016, 01:32:16 am
content: No idea, it does say -DC Voltage: 3~5V DC on its specs though.http://www.ebay.co.uk/itm/391190369647?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

author: TheSteve
author_rank: Unknown
timestamp: January 02, 2016, 02:04:31 am
content: Quote from: Deathwish on January 02, 2016, 01:32:16 amI highly doubt that antenna would survive any kind of real marine environment. Anyway, it likely is defective, unless it is just a total POS. I'd stick with name brand - its not hard to get Trimble branded antennas that are very affordable and work great.

author: edpalmer42
author_rank: Super Contributor
timestamp: January 07, 2016, 01:51:19 am
content: Hi Dave,I finally got around to testing your mod to increase the signal level. It works on my board as you described, but with a twist. With the solder bodge in place, the output level is ~-6 dBm into 50 ohms. The MACT switch hasNOeffect on the output level. With the bodge removed, the output level is ~-24 dBm into 50 ohms until you push the MACT button which changes the output level to ~+6dBm into 50 ohms.My unit lists the firmware version as "firmware ver 1.0.0.2-01 W-CDMA mode".Ed

author: TheSteve
author_rank: Unknown
timestamp: January 07, 2016, 03:14:53 am
content: Does it also switch to the higher output level after it has locked(10 to 20 minutes or so)?That is the behavior of my Trimble with the 63090 OCXO.

author: davebb
author_rank: Frequent Contributor
timestamp: January 07, 2016, 03:20:58 am
content: Hi EdSo when you switch the unit on with the antenna conectedand leave it with out pressing the switchThe level should go high after a few minutesWhen led is flashing fast lockDave

author: davebb
author_rank: Frequent Contributor
timestamp: January 07, 2016, 04:49:35 pm
content: Hi Ed your firmware version is the same as mineDo you get the 1pps out of the RF connectorThanks Dave

author: edpalmer42
author_rank: Super Contributor
timestamp: January 08, 2016, 02:27:27 am
content: Hi Dave,Yes to both your questions.The 10 MHz output switches on after the led is flashing fast lock. I'm guessing that the non-lock status of the 10 MHz either wasn't documented properly by the purchaser or they just missed it so the solder bodge was the easiest fix.The 1 PPS output is present on J4 whether the board is locked or not. It's 10 us wide, 3V high. Nice sharp square wave. It took me about a minute to find it and display it on my old analog storage scope. It works best if you set the triggering to normal rather than auto and DC coupling rather than AC. Not sure how that translates to a DSO.Ed

author: davebb
author_rank: Frequent Contributor
timestamp: January 08, 2016, 11:26:33 am
content: Hi EdGlad it all works fine,When it was outputting only 300mv,it could lock any off my gear,I hope people that have got this model find this post,could I light a LED with the 1pps?Thanks Dave

author: edpalmer42
author_rank: Super Contributor
timestamp: January 08, 2016, 06:04:11 pm
content: Quote from: davebb on January 08, 2016, 11:26:33 amThe pulse is so short that you wouldn't see it, but you could use it to trigger a one-shot with a pulse width of a few hundred ms.Ed

author: davebb
author_rank: Frequent Contributor
timestamp: January 08, 2016, 06:16:56 pm
content: OK thanksDave 2E0DMB

author: Bryan
author_rank: Frequent Contributor
timestamp: December 31, 2016, 09:55:22 pm
content: How many satellites can the "65256" see, is it 10?