Hi Stefan thanks for the advice.

I also found online those additional steps to stop and disable the gpsd socket and then to start manually. I found a lot of info for using the RaPi as an NTP server in David Taylor's satsignal.eu website. I'm assuming when installing ntp and gpsd, autostart commands were placed in a boot configuration file - I'm still looking for it....

I see from ntpq - p that  you left the on-line ntp servers operational, in addition to your gps (I understood Paul's email to disable external ntp by removing these lines as part of the ntp.conf modification)

My gps USB id =ACM0.

Unfortunately, even with all this advice, still no sign of gps synchronisation....but this has helped confirm I have set-up the basic system correctly, so it must be a simple error..and I have plenty of time!

In your photo of the complete assembly, it is interesting to see your modifications. I can see clearly the gps interface connected to the RaPi gpio pins extended through the Octo board. It looks as though you have made your own interface plug for the input of the Octo and using only Ch1, Ch2 with Ch3 as PPS?.

What are the two vertical boards on the left? the smaller one looks like (but not exactly) the DC/DC inverter. Also a direct power connection to the RaPi, as you are not using the microUSB power connector.

Have you added the modifications to give the RaPi a "soft" on/off switch (to protect the SDCard) and a reset button?

Finally, I see you have a USB plug connected - is this for the wifi? I think you are using a RaPi2 without an onboard wifi..and I remember from your earlier posts that you are using 2.4 GHz WiFi to link from your remote forest listening post back to your main site in the University. This must be a LoS path? Even so, quite impressive to work with the interference from the mass of other Wifi in the city...   It gives me the thought to run a RaPi system at my local radio club which is in a relatively radio-quiet site outside the City of Doncaster. But this is about 12km away and not LoS. It would be a good LF/VLF education for the members as their main interest is microwave and nanowaves (light transmissions).....

73 Terry

Hi Terry,

Am 06.08.2017 13:07, schrieb Terry G0EZY:

Hi Stefan

Did you get gpsd and ntp working by following Paul's info (email 21/07)?

No, but his advice was an important step forward. I took additional advice from the web and after some time i got it working.

I have a UBlox NEO 7M connected to the RasPi by USB and I can run xgps or cgps and see that the NMEA is being read. But ntp is not being updated by the gps...

I'm using a NEO 6M and i used the serial interface on the GPIO board. You just need two short wires to realise the communication.
Like that: http://www.iup.uni-heidelberg.de/schaefer_vlf/VLF/20170807_152938.jpg

I have been at the point where you are hanging now. The main steps i did to get it running were:
sudo systemctl stop gpsd.socket
sudo systemctl disable gpsd.socket
then start the service manually with:
sudo gpsd –n -F /var/run/gpsd.sock /dev/ttyAMA0
Replace AMA0 by your individual ID of the USB serial interface if you want to use that.
I added:

server 127.127.28.0 prefer

fudge 127.127.28.0 time1 0.055 refid GPS
to /etc/ntp.conf
Afterwards sudo service ntp restart is required.
I checked if it works by running ntpq –p and got this result:

pi3@Pi8:~/script $ ntpq -p

     remote           refid      st t when poll reach   delay   offset  jitter

==============================================================================

*SHM(0)          .GPS.            0 l   47   64  377    0.000  297.483 137.453

 v20819.php-frie .STEP.          16 u    - 1024    0    0.000    0.000   0.000

 ole.klickmich.o .STEP.          16 u    - 1024    0    0.000    0.000   0.000

 ntp.fanlin.de   .STEP.          16 u    - 1024    0    0.000    0.000   0.000

+ptbtime1.ptb.de .PTB.            1 u  134   64  336   15.411  356.851 150.343

For my portable recorder i'm running a script that checks the difference between system time and GPS time. It is running a while loop until the time difference becomes less than 2 seconds. This tells that the clock has been set by GPS. Then the script continues to start all the vt processes.
Soon i'm going to run an EbNaut transmission on 3675 Hz to see if i can decode it only by using vlfrx tools and EbNaut.

Once I have that problem solved and built the PPS shaper, I can make progress with the Octo soundcard project.

Paul made it seem so easy...!

Yes, if you know how it works then it appears to be easy. Like driving a car, or solving mathematic equations...

I followed your recommendation and bought some of the DC/DC converters from Amazon. Do they require any additional filtering?

No additional filtering is required (i can't know about your individual situation however). Anyway i put 1000 uF onto the output, just to be prepared for any eventualities.
After years i did not discover QRM on LF/MF/VLF. I'm using this converter on the tree as well.

73, Stefan

73 Terry