Gps Sync Down

Giuseppe · November 28, 2014, 12:57pm

First. sorry for my english but i try to explain.

I have 4 Ap EPMP 1000 gps sync, but 2 of 4 don't receive signal from GPS and i have ever GPS sync down.

How i can solve this problem?

Jan  1 00:02:47 Diff kernel: VAP device ath0 created 
Jan  1 00:02:48 Diff kernel: GPS Sync Lost. (00:02:48:206946)
Jan  1 14:44:13 Diff kernel: GPS Sync Restored. (14:44:13:843806)
Jan  1 14:45:11 Diff kernel: GPS Sync Lost. (14:45:11:340034)
Jan  4 14:05:12 Diff kernel: GPS Sync Lost. (14:05:12:662753)
Jan  4 14:05:12 Diff kernel: GPS Sync Lost. (14:05:12:665776)
Jan  4 14:05:12 Diff kernel: GPS Sync Lost. (14:05:12:725584)
Jan  4 14:05:15 Diff kernel: VAP device ath0 created 
Jan  4 14:05:15 Diff kernel: GPS Sync Lost. (14:05:15:830892)
Jan  4 14:15:21 Diff kernel: GPS Sync Lost. (14:15:21:332782)
Jan  4 14:15:21 Diff kernel: GPS Sync Lost. (14:15:21:335807)
Jan  4 14:15:21 Diff kernel: GPS Sync Lost. (14:15:21:392830)
Jan  4 14:15:23 Diff kernel: VAP device ath0 created 
Jan  4 15:57:44 Diff kernel: GPS Sync Lost. (15:57:44:192829)
Jan  4 15:57:46 Diff kernel: VAP device ath0 created 
Jan  4 16:01:43 Diff kernel: GPS Sync Lost. (16:01:43:22821)
Jan  4 16:01:45 Diff kernel: VAP device ath0 created 
Jan  4 16:02:00 Diff kernel: GPS Sync Lost. (16:02:00:512919)
Jan  4 16:02:02 Diff kernel: VAP device ath0 created 
Jan  4 16:02:03 Diff kernel: GPS Sync Lost. (16:02:03:605623)

jluthman · November 28, 2014, 5:17pm

Do you have the GPS antenna attached? Is it mounted to where it can see the sky clearly?

Alejo_Martin · November 28, 2014, 7:10pm

Hi

Do you have de last firmware versión of the GPS chipset?

Giuseppe · November 29, 2014, 1:59am

sure the antenna is attached .... and repeat i have 4 AP and on 2 AP it work correctly on other 2 (in the same position) there's GPS sync down so the sky don't is the problem

Giuseppe · November 29, 2014, 2:01am

Main Software

Software Version (Active Bank)

2.3

Software Version (Inactive Bank)

2.1

Firmware Version

AXN_1.51_2838

Giuseppe · November 29, 2014, 6:02pm

an  1 04:30:08 DiffManfredi1 kernel: Reseting On-Board GPS.......
Jan  1 04:30:09 DiffManfredi1 kernel: $PGACK,101*42
Jan  1 04:30:09 DiffManfredi1 kernel: $PGACK,201*41
Jan  1 04:30:09 DiffManfredi1 kernel: $PMTK011,MTKGPS*08
Jan  1 04:30:09 DiffManfredi1 kernel: $PMTK010,001*2E
Jan  1 04:50:08 DiffManfredi1 kernel: Reseting On-Board GPS.......
Jan  1 04:50:09 DiffManfredi1 kernel: $PGACK,101*42
Jan  1 04:50:09 DiffManfredi1 kernel: $PGACK,201*41
Jan  1 04:50:09 DiffManfredi1 kernel: $PMTK011,MTKGPS*08
Jan  1 04:50:09 DiffManfredi1 kernel: $PMTK010,001*2E
Jan  1 05:10:08 DiffManfredi1 kernel: Reseting On-Board GPS.......
Jan  1 05:10:09 DiffManfredi1 kernel: $PGACK,101*42
Jan  1 05:10:09 DiffManfredi1 kernel: $PGACK,201*41
Jan  1 05:10:09 DiffManfredi1 kernel: $PMTK011,MTKGPS*08
Jan  1 05:10:09 DiffManfredi1 kernel: $PMTK010,001*2E

Alejo_Martin · December 1, 2014, 12:21pm

Please try to uppgrade again to 2.3 Firmware version and the GPS firmware to.

Giuseppe · December 1, 2014, 1:10pm

i already have 2.3

Alejo_Martin · December 1, 2014, 1:15pm

Yes but only in the primary bank of memory.

On AP with GPS Sync you have to do the upgrade twice. And try to performe upgrade on GPS chipset again.

Giuseppe · December 1, 2014, 1:54pm

GPS time (Greenwich Mean Time)	13:53:02
GPS Firmware Version	AXN_1.51_2838
Satellites Tracked	0
Satellites Visible	11

i have this situation.. 11 visible but 0 tracked..

Luis · December 1, 2014, 6:25pm

Hello Giuseppe,

From the description of your problem, it could be an issue with the GPS antenna itself, where the received signal is too low, preventing the GPS chip from acquiring/tracking satellites, even though they are visible. Have you tried replacing the GPS antenna with a known good/tested antenna?

As as side note, please ensure the top of the GPS antenna is facing the sky, as in the attached pic below.

ScreenHunter_80 Dec. 01 12.23.jpg

Thanks,

Luis

Cory_Ditzel · December 2, 2014, 3:00pm

Giuseppe,

I had a similar issue. I could see between 4 satellites and 10 satellites, and track anywhere from 0-4 of them. Replacing the GPS antenna puck fixed the issue. I can now see 11 satellites, and I am tracking 7 of them. Try replacing the puck.

Giuseppe · December 17, 2014, 2:23am

i have do this change and now i tracked 7 satellites

GPS Firmware Version	AXN_1.51_2838
Satellites Tracked	7
Satellites Visible	11

but if i enable the sync gps the ap still not receive the gps signal

Luis · December 17, 2014, 2:56am

Hello Giuseppe,

Tracking 7 satellites should be enough for your AP to work with GPS Sync as long as they have a good SNR (like 25 or more). Can you verify the following:

- Under the Configuration->Radio page, under the Scheduler section, you have either 75/25, 50/50 or 30/70 option selected. The Flexible option cannot be used with GPS Sync.

- Under the Configuration->Radio page, under the Synchronization section, the Syncronization option is set to GPS.

- In the Home page, Sync Source Status shows GPS Sync Up

In the Monitor->GPS page, what levels of Signal-to-Noise ratios are been displayed for those tracked satellites?

Regards,

Luis

Giuseppe · December 17, 2014, 1:57pm

hi,

now i have this situation

GPS Firmware Version	AXN_1.51_2838
Satellites Tracked	0
Satellites Visible	14

here is the photo of my situation. I've try also to put the gps over the top of antenna but i have the same no signal from gps.

Cambium_Sri · December 17, 2014, 2:48pm

Hi Giuseppe,

What are the SNR levels seen for these satelllites?

Also, are there any other AM/FM radios on this roof or nearby roofs or is it only ePMP?

Thanks,

Sriram

Giuseppe · December 17, 2014, 4:53pm

There's only a UMTS repeater on the same roof and the SNR is 0 to all

Cambium_Sri · December 17, 2014, 4:59pm

Hi Giuseppe,

An SNR of 0 for all the satellites indicates that another radio (potentially the UMTS repeater) is wiping out the GPS signal which operates in the 1.5GHz frequency range. Do you know the frequency on which the UMTS radio is operating on? Even if its not on or near 1.5 GHz, it could be the hormonics that's causing interference at the ePMP GPS reciever.

Thanks,

Sriram

Cambium_Sri · December 17, 2014, 6:45pm

Hi Giuseppe,

Just as a last ditch effort, have you tried disconnecting the external GPS puck antenna and let the internal patch antenna take over? Perhaps we may have better luck with that due to the external antenna not amplifing the noise anymore. Just a thought.

Thanks,

Sriram

Giuseppe · December 19, 2014, 2:04pm

@Cambium_Sri wrote:
Hi Giuseppe,

Just as a last ditch effort, have you tried disconnecting the external GPS puck antenna and let the internal patch antenna take over? Perhaps we may have better luck with that due to the external antenna not amplifing the noise anymore. Just a thought.

Thanks,
Sriram

hi thanks for the information, tomorrow i'll go on the tower and i can try this other solution, but there's another solution if it don't work?