Phase Lock Loop Error

Oh, man that sounds expensive.

Sorry to be of no help.

JA, PLS SoCal

Since you're frustrated and in the field I'm going to avoid a humorous reply that involves any of the words "Scotty, Enterprise, warp drives or di-lithium crystals".

Hope you figger it out and salvage the day.

The PLL is probably the one that makes the operating frequency by reference to a crystal standard.

Diagnosis from someone who has never seen that unit: If the battery and operating temperature are normal, then it is most likely a failure that will require a new receiver board. I doubt the repair service gets into troubleshooting individual components on the board.

If recall from my college days studying electronics a phase lock loop is a fairly common circuit used in all kinds of things.
You may be having a internal electronic failure [hopefully not] or possibly just low battery.
Try a fresh battery or maybe just do full restart.

> Anyone know the likely cause of a phase lock loop error message in a Trimble 4000SSi?

Do I recall reading on the UNAVCO site that it is thought to be associated with the use of detergent bottles as battery carriers? (I found no reference to that error message in the 4000ssi User Guide I have.)

A little late on replying; I was out in the field.

If I remember right, when your receiver detects a satellite it tracks it using the C/A code. Once the code tracking is locked, it tries to track the carrier phase using a phase lock loop. An error in in PLL would indicate some issue tracking the movement of at least one SV on the carrier phase.

I'd try rebooting the receiver, looking at skyview to see what SVs are locking, and when you see the one that's causing the PLL error, disable it to see if you can get past the issue.

Might work, based on my understanding of what's going in that magic box that tells me where I am in the world... if not, then my advice is don't take advice from people on the internet.

Any way to know which satellite?

By eliminations note all the satellites you have data for and compare to planning what was in the sky.

It may be the error you will continue to see when C/A is turned off. i.e. your 4000 may truly become end of life.

Paul in PA

😀

> I'd try rebooting the receiver, looking at skyview to see what SVs are locking, and when you see the one that's causing the PLL error, disable it to see if you can get past the issue.

I didn't have a chance to do any testing yesterday. The operator read me the error message over the phone, and said that it wasn't locking on any SVs. I'll take the receiver with me today and set it up during one of my sessions to see what I can learn.

Hi,

i reply only on the behalf of the principle of this issue:

usually when ever in a (radio)system there is a Phase Locked Loop, the stuff has something to do with PLL voltage.

If one knows where to measure it, how many Volts should it be, and from where to adjust it, then it is not a big operation.

A qualified radio mechanic should be able to perform the task.

Problem usually is, that specs and schematics for the tools of trade are well kept secrets of the manufacturers.

best regards
I.A.

When I fired up the receiver this morning it couldn't find any SVs. I did a hard reset, let it download an almanac, and it seems to be working fine now. I'll run my next sessions with it to see if it holds up.

Some of these units are 20 years old, so I won't be surprised if they decide it's time to quit working in the near future. They've given yeoman service, and have earned retirement whenever they're ready for it.

I got 3 sessions logged without incident, but when I started the 4th I got the error message:

A hard reset had no effect. The problem occurred around the same time yesterday, so I'm wondering if it's temperature-related. It's about 90° now, whereas when I started this morning was only around 70°.

Considering that we see the same constellation every day with a 3:56 offset... what satellite is rising above 15 degrees at the time the error occurs?

Great question, so let me refine the time variables. Yesterday the problem cropped up somewhere around noon. Today it happened at about 12:40.

FYI, I let the receiver cool for a session, and when I turned it back on 2:35 it was working again.

> Considering that we see the same constellation every day with a 3:56 offset... what satellite is rising above 15 degrees at the time the error occurs?

About noon, SV G21 would have been coming up. Might have had SV G31 right on the horizon as well with a 15° cutoff in Davis.

Interesting that the range is so wide. It sounds exactly like what I'd expect from multipath; having trouble locking on using the carrier phase, but two events in different places at the same time of day sounds more like an issue with a particular SV or a heat problem.

I went and showed my nerd side by looking at the NOAA space weather prediction center and satellite environment plot, no issues over the last few days that I can see.

I suppose putting the antenna outside the truck and the receiver inside, cords through the mostly closed window, with the AC on would be a test of if it's a heat problem... probably just throwing out ideas that you've already tried at this point though.

Edit- This link has a study performed on the effects of temperature variation on different receivers. More to show the drift of the PLL as temperature changes, but they do lay out that temperature can affect the ability of the receiver to lock.

> A hard reset had no effect. The problem occurred around the same time yesterday, so I'm wondering if it's temperature-related. It's about 90° now, whereas when I started this morning was only around 70°.

Should one assume that you shade the receiver, as in putting it in the box, but with the lid partly open and the box oriented so the lid acts as a shade?

I have used my 4000ssi plenty of times in 100°F+ weather with that simple precaution.

> Should one assume that you shade the receiver, as in putting it in the box, but with the lid partly open and the box oriented so the lid acts as a shade?

Yes, that's SOP. I've also run many sessions in 100+ weather with no ill effects save for the display blacking out if left in direct sunlight, and we had 3 other similar receivers (4 if you count the spare that got placed into service) running at the same time, so it's not a matter of unusual heat conditions. If heat is the problem, it's something unique to that one receiver, perhaps a component on the verge of failure.