SPS 851 was plugged into the wall charger in the office trailer and has battery, so I don't think it was a power issue, nobody was in ther at the time. Foreman shut it off, then back on, was "waiting to acquire satellites" for at least 30 minutes, I don't know if it ever started back up before quitting time. Tech had said to just leave it on 24/7, but that doesn't look like it will work either. After 3 different bases, antennas, and cables, I don' t see another one being the answer.
Interference seems to be the likely cause, may be hard to find where it's coming from.
Two things I would try to "trouble shoot" it.
1) Try running it off internal batteries. If, for some odd reason, the power supply is not steady, it may be constantly powering on/off without you even realizing it. I had a tech tell me once that smooth, clean, regulated electricity is very important to GPS. The interference you may be getting on the construction site might be due to an overload on the power end, rather than the airwaves.
2) You said the Foreman shut the unit down, and turned it back on, and then it messed up again. Unfortunately, that doesn't eliminate a potential memory loss/almanac problem. If it had quit mid-stream, I'd agree that memory/almanac is not the problem. Is there anything unusual you do to shut down/turn on these units? Like one of those procedures where you hold the power button for 10 seconds, or some such thing? This might be something to quickly review with your foreman and tech.
I agree, it could be more than one problem. The slow start-up surely points to the almanac but doesn't account for the unit crapping out mid-day.
Usually, interference is a spotty (a few seconds) event like someone keying a radio close to the receiver, but that's different than if something is stomping on GPS frequencies. GPS interference is serious business and those around that area would probably be feeling it too.
> Two things I would try to "trouble shoot" it.
>
> 1) Try running it off internal batteries. If, for some odd reason, the power supply is not steady, it may be constantly powering on/off without you even realizing it. I had a tech tell me once that smooth, clean, regulated electricity is very important to GPS. The interference you may be getting on the construction site might be due to an overload on the power end, rather than the airwaves.
>
> 2) You said the Foreman shut the unit down, and turned it back on, and then it messed up again. Unfortunately, that doesn't eliminate a potential memory loss/almanac problem. If it had quit mid-stream, I'd agree that memory/almanac is not the problem. Is there anything unusual you do to shut down/turn on these units? Like one of those procedures where you hold the power button for 10 seconds, or some such thing? This might be something to quickly review with your foreman and tech.
Sat Al, In eddycreek's follow up, he said:
"Foreman shut it off, then back on, was "waiting to acquire satellites" for at least 30 minutes"
In other words, it didn't suddenly quit, it sounds like it was working until the foreman powered it down, then when it was turned it back on, it couldn't find satellites. I'm still leaning towards to a memory loss issue at power on or off, but it really doesn't make sense that multiple units all started suffering from the same problem at the same time. It's definitely a strange problem, hopefully the updates will keep coming because I'm very curious on this one.
Have them start a log and note each time that it cuts out. After a few days see if there is a pattern. Compar that to everything you can think of, local transmissions, power, etc.
My APC both at my house and offce started beeping at certain times of the day. Noticed it because it seemed to be near the same time, both locations, same times of each day. Found out the power Co changed us to 'smart' meters. Meters were communicating to teh office (4 to 6 times a day!) and it was tripping my APCs. Power Co said that was rare and actually bought me new units. Doesn't make me feel any better though.
True, true.
Hard to troubleshoot from afar.
I assumed it shut off mid-day by itself.
If the issue is only on start-up, then still points to the almanac.
> Sat Al, In eddycreek's follow up, he said:
>
> "Foreman shut it off, then back on, was "waiting to acquire satellites" for at least 30 minutes"
>
> In other words, it didn't suddenly quit, it sounds like it was working until the foreman powered it down, then when it was turned it back on, it couldn't find satellites. I'm still leaning towards to a memory loss issue at power on or off, but it really doesn't make sense that multiple units all started suffering from the same problem at the same time. It's definitely a strange problem, hopefully the updates will keep coming because I'm very curious on this one.
Correct, the dozer guys reported no corrections about 3:30 in the afternoon. When the foreman went back to the trailer to check on it it showed 0 satellites. Waited a few minutes, it didn't pick any up, so he shut it off and then turned it back on. Never did start receiving, left it on all night, still not working this morning. I was going to take a different base to one of the calibration points this morning and establish a new base back on the site away from the trailer, but when I got there, it was working again. Went ahead and put in a new point in case it stopped again, which it did about 1:30 this afternoon. After waiting 30 minutes with no results, the foreman took it all down, moved it to the new point, which is maybe 1000 ft from the trailer, set it up and it worked. At least it was the last I heard.
Sounds like a really frustrating problem, and your explanation cleared up that it's not just a problem at power on, since it lost sats during operation.
When the unit was moved 1000' from the trailer, were you still on external power, or did you switch to batteries or another power source?
Using internal battery for now.
This is the site. Trailer is one of those you see in the line of trailers above the green hole. Right now the dozers are working in the spoil area at the top above the hoop structures. This was taken in March when the water was up. Smithland Dam is just to the left, Ohio River, just above the confluence of the Cumberland River .
If you can go a couple days without problems using the batteries, it may be a power supply problem. I mentioned this earlier in the thread, but I've been told by techs that "noisy" electric power can effect radio reception. This was when were trouble shooting a robot, but a GPS is basically a radio receiver, so the same might apply. I always thought if the light was on, then the power is good, but apparently that's not always the case. From the looks of that site, other equipment may be causing fluctuation.
Didn't get any "this thang ain't workin" calls today, they used it at the new location on the battery as far as I know.
We started loosing range on ours. Ended up being the radio. I'd suggest getting it looked at.