trimble thunderbolt: no satellites 🛰️ - Page 1
Forum section: electronics / general

author: Jan Catrysse
author_rank: Contributor
timestamp: November 30, 2020, 09:27:28 pm
content: Hello,I had a trimble thunderbolt running the whole summer and when checking today, it seems I lost satellite tracking. I am new to this.But I don't know what is wrong or how to diagnose it. I tried a power cycle and factory reset. The only thing I get is attached in this post.It seems the time is getting in, but no satellite fixes.I checked the bias of the antenne, it was about 5 volts.What could be wrong? Or how could I check it further?The GPS antenna is about 5 meters from the house but only about 50cm from the ground. Could this be seasonal? Is my house blocking the signal this time of year?Advice is welcome.Thank you.

author: thinkfat
author_rank: Unknown
timestamp: December 01, 2020, 10:06:29 am
content: Apart from not reporting any sats, from the rest of the panel everything looks goodIt's doing fixes, the time uncertainty is just a bit over 2ns, which is totally fine, it's in overdetermined clock mode and the PLL is locked.Everything looks in good shape.

author: Jan Catrysse
author_rank: Contributor
timestamp: December 01, 2020, 04:02:33 pm
content: Thanks. Well... that is kind of good newsCan anyone tell me what the impact is on the time signal / accuracy ?Has someone got an explication? It has always shown a few good SV's...I don't get it.

author: DaJMasta
author_rank: Super Contributor
timestamp: December 01, 2020, 10:58:45 pm
content: Could it be due to changes in surroundings? I don't know how the receiver in a Thunderbolt fares, but I've had other older but high performance timing receivers be very sensitive to antenna angle and amount of sky view when not mounted in optimal locations - it could be that a little flex in the mount or some extra foliage cover or something has degraded your signal from the initial installation.

author: cdev
author_rank: Super Contributor
timestamp: December 02, 2020, 03:39:43 am
content: Check inside your antenna for water leakage, sometimes the combination inside of cheap GPS antennas adds up to a bad situation. I read a paper some time ago about just such a situation in a small boat marina that held a lot of fishing boats.. One of the boats antennae became a GPS signal source which made GPS equipment for a considerable distance malfunction. It was cited on time-nuts.

author: edpalmer42
author_rank: Super Contributor
timestamp: December 02, 2020, 04:17:47 am
content: Before you start tearing hardware apart, have you tried a different program? I think most people use Lady Heather to monitor their Tbolt. Tboltmon is a very old program. Maybe it's choking on some of the new satellite SVs or some other characteristic that Tbolt is reporting.QuoteSVN76 was launched on June 30 and went operational on Oct. 1.Since most of the data shown is correct and complete, the Tbolt*must*be getting solid signals from multiple satellites.

author: Jan Catrysse
author_rank: Contributor
timestamp: December 02, 2020, 01:44:05 pm
content: Thank you for the suggestions.Before opening my hardware I am trying to understand what is happening.My antenna should be completely watertight, I already checked the (screw on) connectors, and they are dry.If I can't figure out anything else I will check the antenna and the thunderbolt, but for the moment that is on hold.This is what I get with Lady Heather... the strange thing is that the maps are disappearing after a few seconds, I added two screenshots.

author: edpalmer42
author_rank: Super Contributor
timestamp: December 03, 2020, 02:48:32 am
content: So LH starts up with the first screen capture and then after a few seconds changes to the second capture and just sits there?? It doesn't fill in any more of the screen? Then the problem seems to be with the Tbolt rather than the software. My Tbolt/LH experience is limited. The author of LH, Texaspyro, is a member here and would be able to offer more assistance.

author: Jan Catrysse
author_rank: Contributor
timestamp: December 03, 2020, 07:10:03 am
content: That is indeed correct.

author: Ash
author_rank: Regular Contributor
timestamp: December 03, 2020, 07:46:41 am
content: So the Date shown in the screen shots is 2001.The GPS Epoch rolled over a while ago, perhaps the Thunderbolt is not able to correctly interpret the data/date properly and is getting confused. I know that a lot of manufactures had to issue firmware updates to handle this.. but I'm far from being an expert in this stuff. Just something I remember looking at.* Epoch may not be the right word.. Its the week counter I think. something like a 10 bit number. First rolled over in 1999, and then again 2019. Which might explain why your clock thinks it is 2001 (about a year after rollover).Ash.

author: Jan Catrysse
author_rank: Contributor
timestamp: December 03, 2020, 09:27:02 am
content: That is indeed a limitation, the date is always about 20 years behind schedule. But that is normal.

author: edpalmer42
author_rank: Super Contributor
timestamp: December 03, 2020, 04:56:05 pm
content: Yes, the Tbolt has aged to the point where the GPS rollover causes the date to be 1024 weeks behind. The last time the Tbolt was correct was in 2017. Normally, LH catches that and corrects the date, but it takes a short time for that to occur. Looks like things get confused before that happens.

author: w9gb
author_rank: Contributor
timestamp: December 03, 2020, 05:47:14 pm
content: Your Posted Display (Thunderbolt Monitor)shows that NO GPS Signals are being Received / Data Output to your Computer.—CHECK YOUR ANTENNA, COAX, CONNECTORSUse a SECOND +5 Volt GPS Antenna ... to Verify.CAUTION: NEWER GPS Antennas are often ONLY +3.3 Volt ... and can damage antenna or Thunderbolt.I have a Trimble Thunderbolt (RED), Surplus from a 911 Call Center when 2019 WNRO Event occurred.Running very well with Lady Heather version 6.14Beta.** IF you are using a Serial to USB converter ...Latest Windows 10 has a BUG for USB 3.0 hubs.Microsoft promises “fix” ASAP (likely next 4 weeks).**==Week Number RollOver (WNRO) is a known GPS issue,NOT corrected by MANY GPS manufacturers (firmware oversight, planned obsolescence, etc.)https://www.trimble.com/WNRO/The First GPS WNRO event occurred in 1999.The Second WNRO occurred on April 6, 2019, at GPS Midnight.—The Trimble Thunderbolt (RED and older OEM models) is NOT Upgradable by Trimble.http://www.leapsecond.com/pages/tbolt/Thunderbolt-2003-11.pdfTrimble sells the Thunderbolt-E (BLUE label) as the replacement.https://www.trimble.com/Timing/thunderbolt-e.aspx—LADY HEATHER (LH) version 6.xx BETA for Windows corrects the WNRO problem with its display.TEXASPYRO posted the Link and INSTRUCTIONS here on EEVBLOG (February 22, 2018)https://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/msg1434005/#msg1434005===greg, w9gbchicago

author: Jan Catrysse
author_rank: Contributor
timestamp: December 03, 2020, 08:17:41 pm
content: OMGQuoteUsing another USB to serial cable fixed it! Now I am using an USB 2 port and not the integrated serial port of my docking station (internally connected to USB 3.0)Jezus... go figure... thanks man!I attached new screenshots.Whoop whoop.

author: edpalmer42
author_rank: Super Contributor
timestamp: December 03, 2020, 09:44:01 pm
content: I've seen lots of problems caused by USB/Serial converters, but never one this subtle. Most converters output levels of +5 and ground. That usually works, but not always. RS-232 is actually supposed to be > +3V and < -3V, i.e. bipolar. Converters that actually specify their output voltages are quite rare.

author: thinkfat
author_rank: Unknown
timestamp: December 04, 2020, 07:20:02 am
content: Quote from: edpalmer42 on December 03, 2020, 09:44:01 pmI know of one other occasion where a faulty FTDI converter corrupted the NAV5 messages from a NEO Ublox module. Just those. Rare events, but they happen.

author: notfaded1
author_rank: Frequent Contributor
timestamp: December 08, 2020, 04:02:53 pm
content: I've had the same problem before. It's very hard to diagnose too because it can lead you down many other rabbit holes. When you finally figure it out it's really an insane realization the stupid USB to RS-232 cable has failed you!!!Bill

author: Jan Catrysse
author_rank: Contributor
timestamp: December 08, 2020, 04:27:34 pm
content: In the meantime I have noticed that I need to reconnect the USB cable from time to time to make it work.But the Thunderbolt is doing its work.