FM-1000 (FMX) no satellites

[clbarclay]

The FM-1000 screen I still use for an isobus fert spreader has been temperamental in recent years, since it has had to share cab space with agopengps. I doubt that is the reason, but the FM-1000 doesn't see any satellites now. I happened occasionally last year while spreading and seems set in its way now.



While checking settings to hopefully get agopen sending NMEA to it as a serial input, I noticed in the Unlocks menu that while range point is clearly unlocked till next year, the internal gps receiver appears to be locked!




Can someone with a working FMX or FM-1000 using rangepoint please confirm if the internal gps receiver should also appear to be unlocked like the rangepoint is.

 

[clbarclay]

I guess hardly anyone is still using these screens now to check.

 

[clbarclay]

Turns out that locked unlock is for the second internal receiver, used for implement steering. One good thing I found out, if you have done a full file backup, then all your unlock codes are saved in that.


Does anyone in or near Worcestershire have a working system which uses an AG-25 antenna and would test mine to see if that is the cause of my problem?

 

[Northern farmer]

Turns out that locked unlock is for the second internal receiver, used for implement steering. One good thing I found out, if you have done a full file backup, then all your unlock codes are saved in that.


Does anyone in or near Worcestershire have a working system which uses an AG-25 antenna and would test mine to see if that is the cause of my problem?

Couldn't you test the AG-25 antenna with your F9P receiver? I once tested our neighbour's AG-25 and found out with u-center that the antenna was dead at L2 frequencies.

A TNC adapter is needed, I was using the antenna cable from an Ardusimple "survey GNSS antenna".

 

[clbarclay]

It hadn't crossed my mind that a f9p could be used to do that.

How do you test an antenna in ucenter? Is it a case of just hooking it all up, look at the signals and work out which are absent?

 

[Northern farmer]

I don't have an F9P at reach just now but I think if you enable GSV messages, u-center would show signal levels or SNR levels for each satellite. If I remember right, u-center shows both L1 and L2 levels on a bar graph. Comparing measurements with another antenna (e.g. ANN-MB) at the same position one after the other would give a good idea if the AG-25 is good.

 

[clbarclay]

While checking the which adapter to SMA I need, a not so high tech "shake test" suggests that water inside the ag-25 could well be the cause of the problem.

 

[Soon_60]

If your shake test is positive then it is deaf. Might start working if stored on top of a hot furnace for a month or two...

I have bought several lower cost Chinese L1/L2 antennas. All of the have worked well and only some have failed after some years.
For what they cost they are good and you can afford to have a couple of spare ones at home.
Most of them need a magnet leg.
The on in the enclose picture has proven to be very good and robust.

 

[clbarclay]

I read a post on here about someone removing the top cover and cleaning them up inside to get them working again. So far I haven't got the top of trying to be gentle with the heat, though if the top does get broken in the process then I could just print a replacement.

 

[Soon_60]

I read a post on here about someone removing the top cover and cleaning them up inside to get them working again. So far I haven't got the top of trying to be gentle with the heat, though if the top does get broken in the process then I could just print a replacement.

What about just drillin couple 5 mm holes on the the top to shake the water out and let it dry for a week an top of the furnace. Then use just some drops of epox clue to fill the holes.

But I really do recommend this Beitian from ebay oli Aliexpress. Its is just about 100 -150 + another 10-15 for a reasonable solid magnetig mount.
A good thing with this some 10 cm high mount is that antenna is a little ways up from the cab roof and not prone to water getting in from the bottom ventilation.

 

[clbarclay]

Finally got round to opening up the antenna with the aid of wafting a lot of heat around the join and gentlish prying with a victorinox can opener.





I was surprised just how much water trickled out when I had the lid almost off. I had noticed what looked like a couple of hairline radial cracks around the 5/8 mount. On the inside, the cracks are more obvious.




Time to clean it up and find out if it will see the satellites again.

 

[clbarclay]

So far, cleaning up the corrosion has got all the GPS and glonas satellites back. It's not seeing the rangepoint correction though.

The tops pop off the box cages, but I haven't disassembled it further, as I think it needs a couple of pins desoldering on the actual antenna to get at the back of the PCB.


It is very nice to be spreading again with auto sections again. The manual two section controls on the KV isobus VT screen are visual nightmare to operate while driving.