GPSDO constantly 'Operation Mode' Settling not Lock - Page 1
Forum section: electronics / general

author: W0MPM
author_rank: Contributor
timestamp: December 08, 2018, 02:31:11 am
content: I've had this GPSDO for a couple weeks:https://www.ebay.com/itm/GPSDO-Symmetricom-Inside-GPS-10MHz-1PPS-GPS-Send-GPS-antenna/263458624856?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3D0e1bdcdd1f6f4217afb5746ffc95c0f6%26pid%3D100005%26rk%3D1%26rkt%3D4%26sd%3D252162780444%26itm%3D263458624856&_trksid=p2047675.c100005.m1851It 'locked' once for a short period at which time it also showed values for the 'osc'. Almost exclusively been 'Settling' and 'osc' has no values. (I installed the Lady Heather V6 beta at which time 'osc' parameter was replaced by 'loop' but that also is not reporting values).What exactly is 'Settling'? Is the 10MHz OCXO being disciplined?Read the ccp and other LH files and 'googled' a bunch; but not finding much is the way of definitions to help understand what Lady Heather is telling me.Thanks

author: cdev
author_rank: Super Contributor
timestamp: December 08, 2018, 03:44:27 am
content: Is it connected to an antenna and if so what kind and how much sky can it see above it? If you're using a patch antenna, you may have better luck if the antenna is attached to some flat horizontally level piece of metal at least the size of a CD/DVD, preferably larger.That is basically essential for good performance with a patch antenna.Also, if it can be commanded to do a survey, has it gotten to do a survey yet? Does it have a 3D lock on at least 3 satellites? It needs a good signal - a good sky view, to lock on to satellites.Is your antenna outdoors? If it is and its not waterproof, you should try it using another antenna. TAPR sells a pretty good basic GPS antenna for $10. But it needs to be placed on a flat metal ground plane, oriented in the horizontal plane, ideally in a window sill (although a cold window sill above a heating vent or radiator is not a good place for a GPSDO because of large temperature fluctuations.)Find a good place for your antenna thats dry and place the GPSDO in an area not subjected to extremes of heat or cold.The GPSDO will always be fairly warm because of its ovened oscillator, thats normal.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 08, 2018, 06:48:39 am
content: I had similar problems and discovered that the wall wart supply I had picked to power the thing was not up to the task. It was dropping below min voltage in the latter part of each power cycle. You might want to verify that you are feeding yours good power.

author: W0MPM
author_rank: Contributor
timestamp: December 08, 2018, 11:42:32 am
content: Thanks Cdev. I think all that is working correctly. More than one survey has been completed.I will double check the 12V supply in use.To reiterate. What does 'Settling' mean especially with reference to the state of the OCXO?

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 08, 2018, 03:29:50 pm
content: Based on watching mines behavior during startup it means the control loop has not closed sufficiently. I have no idea what the criteria for sufficiently is. I believe source code for Lady Heather is available, but I haven't had the motivation to look into it.

author: cdev
author_rank: Super Contributor
timestamp: December 08, 2018, 03:49:48 pm
content: Do you have any other GPS you can use to test the antenna and its location?

author: W0MPM
author_rank: Contributor
timestamp: December 08, 2018, 04:25:59 pm
content: Well Catalina your suggestion re power may have done it. The wart I was using dropped to 11.2V and this unit is spec'd at 12 to 24. Rummaged around and found another twice the rating (1500mA). Now at 12.5 during initial power on and 13.9 now. AND, Lady Heather sez it's LOCKED. We'll see how that holds. It showed Locked once before; maybe this will fix it.Cdev, my previous post I attached a Lady Heather screen. My bad I did not state what it was. But it shows lots of satellites etc.Thanks.I still have some questions about what some of the Lady Heather reports MEAN if someone wants to chime in.John

author: W0MPM
author_rank: Contributor
timestamp: December 08, 2018, 05:20:05 pm
content: What's up with the sudden spike on the 'loop' parameter?

author: cdev
author_rank: Super Contributor
timestamp: December 08, 2018, 05:47:41 pm
content: Looking good!Loop probably means thePhaseLockedLoop'snormal operation is beginning?

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 08, 2018, 08:32:25 pm
content: There is a lot in the Lady Heather manual to learn. I am still working my way through it and don't have it all down by any means.

author: texaspyro
author_rank: Super Contributor
timestamp: December 09, 2018, 03:59:28 am
content: Quote from: W0MPM on December 08, 2018, 11:42:32 amUhhhh.... these "UCCM" receivers run on 6V. 12V will probably fry something... unless you have some boxed unit with an internal power supply.

author: cdev
author_rank: Super Contributor
timestamp: December 09, 2018, 04:45:13 pm
content: He does have a boxed unit with LEDs, jacks, etc. that needs a 12-24v power supply.So it likely has its own internal voltage regulator.So the inadequate power to the regulator may have been his units' problem.Quote from: texaspyro on December 09, 2018, 03:59:28 am