| Koen02 | Posted: 20 Mar 2020, 09:33 AM |
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 Member Posts: 1 Joined: 20-March 20 |
My clock has been sitting outside and behing a window for at least 6 hours. Still no gps fix, it just keeps counting up. I did see the GPSMOD1315 antenna as an option, but shipping is very expensive because i can only get the GPSMOD1315 from the US (I am based in The Netherlands) Is there a gps antenna which is available in europe? (Note: i sourced all components and pcb myself) ------------- |
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| mit | Posted: 20 Mar 2020, 12:56 PM |
 yeah whatever Admin Posts: 566 Joined: 4-May 16 |
Mouser shipping is free if you order more than something like $40. Maybe you could combine it with some other parts you need? Or get a few antennas and re-sell them. But it might not be the antenna that you need. The original antenna works fine for me where I live. It could possibly be the ATtiny needs calibrating - try sending it some fake data with a USB serial adapter. There's a python script in the github repo to do that. It could be the GPS module is a different type, if you sourced it yourself, so also try listening to its output with a USB-serial adapter and see what it's saying. If the GPS module has an LED on it, it will start flashing when it has a fix, so if you see that happening and it still doesn't display the time then the problem is not the antenna. ------------- |
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| Jimsmart | Posted: 28 Apr 2020, 04:21 AM |
 Member Posts: 1 Joined: 27-April 20 |
Hello Mit/Tim, I saw my first digital clock in 1962 at the Parkes Radio Telescope in western NSW, Australia. I resolved to build one day when I had finished uni. That day has arrived. Your Precision Clock kit ticks more boxes that any other I can find and I am keen to build it as soon as the disruptions caused by the Covid 19 are out of the way. I have two reservations of your current kit. I would prefer green LEDs but realise that they can be difficult to find so may have to use red. A tricker problem is that the optimal location in my living room for the clock has close to zero GPS signal strength. This is due to having a layer of aluminium foil in the roof of the house as a part of the thermal insulation.Additionally above the roof is a 22 panel 6kW photovoltaic array. To capture a good GPS signal I will need to instal an external GPS antenna with a 5 metre lead. Such antennas are readily obtainable here - they are used on boats. They usually have a SMA connector. GPS modules using a NEO-6M chip and with a SMA connector are also available. If anyone on this forum has experience with an external GPS antenna on the Mitxela Precision Clock I would be interested to hear of it. Jim Smart, East Maitland, NSW, Australia. ------------- |
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| mit | Posted: 29 Apr 2020, 03:34 PM |
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yeah whatever Admin Posts: 566 Joined: 4-May 16 |
I have not had much success with outdoor antennas with SMA connectors. I am not really sure of the reason why, I had assumed the outdoor antenna I have is expecting a 5V bias voltage, but I'm not sure. A simpler approach is to encase the GPS module and antenna in a waterproof enclosure and have a cable leading back to the clock. The NMEA data is at 9600 baud and should survive a reasonably long cable. You could potentially try out an outdoor antenna with a GPS module if you can get hold of one, and just listen to the serial data output with a USB-UART adapter and maybe the u-Centre software. It can plot nice graphs and lets you do a 24-hour skyview plot, so you can directly compare different antennas and positions. So long as the module is outputting 9600 baud NMEA strings, it will work with the Precision Clock. ------------- |
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