| Andreas | Posted: 16 Mar 2021, 06:19 PM |
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 Member Posts: 11 Joined: 16-February 20 |
Hello! Just a heads up: I am not describing a issue or a problem I am more pointing out something interesting I found while using the clock. Just by some magic I got the clock to get a GPS fix and it had it practically 99.8% of the time. When winter came along it changed quite drastically. Instead of it having a GPS fix all the time it only gets it at a certain period. For instance, my clock seemed to only get a GPS fix at 1 a.m. in the morning, and on no other time. Then it shifted to 9 p.m. and from that to 8 p.m. It would usually last from 10 to 40 minutes before it lost it again. I am guessing the clock has the positions of the satellites remembered and on that exact time they are in that position, so the clock instantly get s a fix. I also noticed that while it has no GPS fix it does fall behind but it still corrects the time if it has no fix. I am guessing it needs multiple satellites in order to get a solid fix but it is also able to correct itself with only one or two. Otherwise, the clock itself works as expected, just some interesting things I noticed about it. ------------- |
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| mit | Posted: 17 Mar 2021, 10:30 AM |
 yeah whatever Admin Posts: 566 Joined: 4-May 16 |
It's very hard to know what's affecting it. It could be some electromagnetic interference from something that wasn't there before. It's possible to listen to the GPS serial data and plot a sky-view to get a better picture of what the signal strength is like, but I'm not sure how much that would help. Are you using the antenna that came with the kit? It's probably worth upgrading to an active antenna if so. ------------- |
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| Andreas | Posted: 17 Mar 2021, 11:23 AM |
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Member Posts: 11 Joined: 16-February 20 |
I am currently using the antenna that came with the kit. Though, I looked into my local electronics shop to find a antenna that would work with it, I got confused since there were so many different ones and I was unsure which I should get since some were for a different purpose. I could send you a link to the shop if you would wish to take a closer look. ------------- |
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| mit | Posted: 18 Mar 2021, 08:15 PM |
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yeah whatever Admin Posts: 566 Joined: 4-May 16 |
Upgrading the antenna will probably make a big difference. Not all antennas will work, take a look at this thread. The 15dB active antenna from pulse larsen works very well. I think Mouser and Digikey should be able to ship worldwide, but if there's a local shop you'd prefer then feel free to list what they have and I can give you my opinion on it. ------------- |
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| Andreas | Posted: 20 Mar 2021, 10:43 AM |
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Member Posts: 11 Joined: 16-February 20 |
Here is the local shop's site: https://www.oomipood.ee/en/product/search?q=gps%20antenna&s=2 ------------- |
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| mit | Posted: 23 Mar 2021, 11:21 PM |
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yeah whatever Admin Posts: 566 Joined: 4-May 16 |
Hi, well, there's certainly a lot to choose from. Since I haven't tested any of those, I don't think I can fully recommend any of them, but I expect many of them will work. It's probably best if I describe the active antennas I've tried out, which are the Trimble 66800-52 (which has an SMA connector, and needs an SMA to u.fl adapter) and the Pulse Larsen GPSMOD1315. - Power supply needs to be 3V - Avoid antennas with too much gain, 33dB is definitely too much. The Pulse antenna is 15dB, the Trimble one says "up to 28dB" - SMA is a much better connector than the tiny u.fl coax on the module, so getting an adapter is a good idea if you want to try out different antennas. ------------- |
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