Topics

kit GPS QLG1 #gps


F1BFU - Fr - 79
 

Hello all
Following the setbacks encountered with my first two QLG1 GPS kits (no pps signal), I have just finished the kit for my third QLG1 and I am having the same problem.
No pps sign on my U3S.
Can you tell me if this problem has already been encountered and what is the source of the problem in order to remedy it.
 have never seen the green LED on once.
4 satellites are tracked.

Gilles F1BFU/FR


Alan G4ZFQ
 

 have never seen the green LED on once.
Gilles,

That is with the all QLG1s just powered up? I mean not connected to the U3S? Once locked the LED should flash.

If you have never tested them without connecting to the U3S I suspect a fault on the U3S causes this problem.
If you have tested them on their own then it looks like something you have done. But it seems unlikely you made the same error 3 times.
If the PPS input to the U3S is grounded by a solder splash or unetched track then maybe that is the problem. I'm not sure but some have had IC1 fail, maybe because of this.

73 Alan G4ZFQ


KEN G4APB
 

Hi Gilles,
more info please. Are you getting a lat/long coordinates indication on your U3S? Four stats sounds too low, you should be seeing many more. 

73 Ken


KEN G4APB
 

Sorry Gilles, got interrupted before I finished...I was going to say for a first start-up of a new gps unit to need to give it a good clear view of the sky to allow a new almanac to download, can take 15 minutes or so. Also you need to be seeing at least 25db c/n values for good data. Only when you have satisfied these conditions can we start to investigate the pps connection. Also check your versions with Hans earlier posts, there were some issued with a firmware problem.

73 Ken G4apb


F1BFU - Fr - 79
 

Hi my friends

I changed my GPS; I connected a GPS with an external antenna and everything is fine.
I will try to unsolder the GPS antenna of my QLG1 Kits and replace with an SMA socket. So I could hook them up to the GPA antenna and see if they all work properly.
Thank you all for your responses.

Gilles F1BFU / Fr


Roger Hill
 

Hi Gilles:

Seems to me there might be something done consistently, but incorrectly. It would IMHO be unlikely to have three kits with all the same problem. Maybe check carefully that the internal antenna is placed and connected correctly, and perhaps that the battery is installed right way up...

73

Roger

G3YTN

---
***************************
Roger Hill
***************************


On 2020-04-22 09:17, F1BFU - Fr - 79 wrote:

Hi my friends

I changed my GPS; I connected a GPS with an external antenna and everything is fine.
I will try to unsolder the GPS antenna of my QLG1 Kits and replace with an SMA socket. So I could hook them up to the GPA antenna and see if they all work properly.
Thank you all for your responses.

Gilles F1BFU / Fr


Hans Summers
 

Hi Gilles

It is indeed strange that a problem would afflict 3 units. 

I wondered also about what power supply you are using? If it was a very noisy switched mode supply I wonder if that could interfere with the RF reception? 

73 Hans G0UPL
http://qrp-labs.com

On Wed, Apr 22, 2020 at 4:35 PM Roger Hill <rhill@...> wrote:

Hi Gilles:

Seems to me there might be something done consistently, but incorrectly. It would IMHO be unlikely to have three kits with all the same problem. Maybe check carefully that the internal antenna is placed and connected correctly, and perhaps that the battery is installed right way up...

73

Roger

G3YTN

---
***************************
Roger Hill
***************************


On 2020-04-22 09:17, F1BFU - Fr - 79 wrote:

Hi my friends

I changed my GPS; I connected a GPS with an external antenna and everything is fine.
I will try to unsolder the GPS antenna of my QLG1 Kits and replace with an SMA socket. So I could hook them up to the GPA antenna and see if they all work properly.
Thank you all for your responses.

Gilles F1BFU / Fr


Don--AE4DW
 

Can you post pics of your boards, both sides?

If its not a construction mistake, same thing 3 times, then would have to be operational, and likely something common, power supply, as Hans notes (try firing it up on batteries). The fact your other gps module works would suggest you should be able to acquire satellites, just would take time to do the first acquisition.

This is the firmware issue that was referred to: http://qrp-labs.com/qlg1/gps2018.html  but if your latest one is a brand new recently shipped  kit, then that suggests its not a firmware issue.

 

 


Samuel KJ4VPI
 

Of course, if you were using the OLG1 inside the case with the provided GPS antenna, that would be a problem. You are getting the Red LED and the Yellow LED? You must be getting the Yellow LED associated with data if the U3S is receiving info from 4-sats... You might have a solder bridge on the U3S that is preventing the 1PPS line from changing state. That would fit with the observed situation that 3oo3 kits now are not working for you. 

Lastly, if you are going to use an external antenna that is connected via an SMA connector to the OLG1 rather than the included antenna, then you must  install the optional L1 and R1. As I recall, the solder pad of L1 closest to the SMA connector location on the board, needs to be connected to the center pin of the SMA connector. If you don't do that, your external antenna is not going to be powered, and it will not provide a signal to the board.

73 KJ4VPI. Sam


Martin Rath <martin.rath@...>
 

Bonjour Gilles,

Are you using the internal antenna or an external one on your QLG ? If you are using an external one, did you fit R10 and L3 ?

Best 73's Martin 9V1RM


On Thu, Apr 23, 2020 at 4:39 PM Samuel KJ4VPI <sernstfortin@...> wrote:
Of course, if you were using the OLG1 inside the case with the provided GPS antenna, that would be a problem. You are getting the Red LED and the Yellow LED? You must be getting the Yellow LED associated with data if the U3S is receiving info from 4-sats... You might have a solder bridge on the U3S that is preventing the 1PPS line from changing state. That would fit with the observed situation that 3oo3 kits now are not working for you. 

Lastly, if you are going to use an external antenna that is connected via an SMA connector to the OLG1 rather than the included antenna, then you must  install the optional L1 and R1. As I recall, the solder pad of L1 closest to the SMA connector location on the board, needs to be connected to the center pin of the SMA connector. If you don't do that, your external antenna is not going to be powered, and it will not provide a signal to the board.

73 KJ4VPI. Sam


Erwin - PE3ES - F4VTQ
 

Gilles,

Mine works like a charm since ages.

It needs a good steady power supply. Did you test all three with same supply?

Can you check with the software of ublox? U-center, via UART/Serial connector to com port?

https://www.u-blox.com/en/product/u-center

73


Graham, VE3GTC
 

GPS Visualizer is another good program for viewing and decoding the NMEA output from GNSS receivers


Apparently it will run on Linux using WINE but I haven't tried.

Now if I could just find a similar program that was native to LINUX ...

cheers, Graham ve3gtc
 


On Thu, Apr 23, 2020 at 12:12 PM Erwin - PE3ES - F4VTQ via groups.io <waterwin2=yahoo.com@groups.io> wrote:
Gilles,

Mine works like a charm since ages.

It needs a good steady power supply. Did you test all three with same supply?

Can you check with the software of ublox? U-center, via UART/Serial connector to com port?

https://www.u-blox.com/en/product/u-center

73


Eric KE6US
 

I've used GPSD for several months on a Raspberry Pi 3b+ with my QLG1 and before that on a 10 year old GPS board adafruit used to sell. It's far more powerful than just a viewer, but you can use it just as a viewer (run gpsmon or cgps) if you want.

It's open source, but used by many commercial GPS product manufacturers like Garmin, etc.  It's written in python. Very well supported. Normally, you can just use gpsd /dev/ttyS0 for a serial connection. Adafruit has a nice installation guide which is simple to follow.

https://learn.adafruit.com/adafruit-ultimate-gps-hat-for-raspberry-pi/use-gpsd

Eric KE6US

On 4/23/2020 5:26 AM, Graham, VE3GTC wrote:
GPS Visualizer is another good program for viewing and decoding the NMEA output from GNSS receivers


Apparently it will run on Linux using WINE but I haven't tried.

Now if I could just find a similar program that was native to LINUX ...

cheers, Graham ve3gtc
 

On Thu, Apr 23, 2020 at 12:12 PM Erwin - PE3ES - F4VTQ via groups.io <waterwin2=yahoo.com@groups.io> wrote:
Gilles,

Mine works like a charm since ages.

It needs a good steady power supply. Did you test all three with same supply?

Can you check with the software of ublox? U-center, via UART/Serial connector to com port?

https://www.u-blox.com/en/product/u-center

73


Kevin Zembower
 

On Thu, Apr 23, 2020 at 08:26 AM, Graham, VE3GTC wrote:
Now if I could just find a similar program that was native to LINUX ...
With GPSD, did you try 'xgps' or 'cgps'?

-Kevin
KC3KZ


Charles Mims
 

A word of caution.  I have GPS running well on a RPI 4.  I use it to keep my time synced when away from home and no internet.

However, the Raspberry Pi 4 running Buster had changed the name of the 'serial' ports so instructions posted on the web would not work.  I am not at my RPi now but if I recall the name now used for the serial ports is /dev/ttySerial0 or something similar.  Check /dev/tty* .

Charles KG5ZLH


Rick Williams - VE7TK
 

I have VisualGPSView running under Linux using WINE.

However, after a few minutes it goes crazy and takes more than 20% of the CPU resources and slows down the computer to a crawl. I haven't quite abandon this but it is getting close to the "doomed project" category!
--
73, Rick
VE7TK


Graham, VE3GTC
 

thank you everyone for the suggestion gpsd and xgps / cgps.  I have been so fixated on my current use of uCenter that I almost completely forgot about xgps and cgps.

I am quite familiar with these tools and the gpsd daemon as I have used them before. xgps is a good alternative to visualGPS on Linux but uBlox uCenter has a feature which these do not and that is the ability to create a sky view display (see attached as an example) which is a 2D representation which shows average SNR of the received signals over azimuth and elevation. I have found this very useful for testing GNSS antennas as it shows how well your antenna is working.

xgps does produce a sky view but I don't think it is accumulative as the one in uCenter.

cheers, Graham ve3gtc

On Thu, Apr 23, 2020 at 6:48 PM Kevin Zembower via groups.io <kzembower=verizon.net@groups.io> wrote:
On Thu, Apr 23, 2020 at 08:26 AM, Graham, VE3GTC wrote:
Now if I could just find a similar program that was native to LINUX ...
With GPSD, did you try 'xgps' or 'cgps'?

-Kevin
KC3KZ