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Astronomic Time Clocks

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hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
SSDriver said:
One of the members here makes them in Florida, I only see 277v on the site. The 120v units I've used are right about $60. Might want to reach out to him and see if he has a 480v version.
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Found the pricing link on his site, it does say they can customize them. If I can get them 480, I have a national customer that they would work great for.
 
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SSDriver

Senior Member
Location
California
Occupation
Electrician
hillbilly1 said:
Will it work in a parking garage though? The electrical room is on an outside corner, but four deck levels above it. Probably will not connect with the satellite signal.
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It's supposed to have line of sight but i have mounted them in wood cabinets on the side of a building with no issue. Some where on the site they recommend a free app to download and you can verify GPS signal with your phone before you install/buy the unit.
 
drcampbell

drcampbell

Senior Member
Location
The Motor City, Michigan USA
Occupation
Registered Professional Engineer
hillbilly1 said:
Will it work in a parking garage though? The electrical room is on an outside corner, but four deck levels above it. Probably will not connect with the satellite signal.
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The satellites need not be directly overhead. Maybe it can get three or four good soundings from oblique angles. And it doesn't need to update the location every second; it can wait for favorable satellite locations.
 
W

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
hillbilly1 said:
Will it work in a parking garage though? The electrical room is on an outside corner, but four deck levels above it. Probably will not connect with the satellite signal.
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I have not used the product but have used quite a bit of GPS hardware at a low level. My strong guess is that this unit will likely work just fine if it can see _some_ sky with minimal interference.

If you need an accurate position fix that updates frequently, then need a good unobstructed sky view to get signals from multiple satellites at the same time. But a stationary receiver that can take a while to get its position fix and then only needs to see 1 satellite now and then to maintain its time fix can get away with a far more obstructed sky view.

This application will work just fine if the position fix is off by multiple kilometers and many minutes.

-Jon
 
G

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
winnie said:
I have not used the product but have used quite a bit of GPS hardware at a low level. My strong guess is that this unit will likely work just fine if it can see _some_ sky with minimal interference.

If you need an accurate position fix that updates frequently, then need a good unobstructed sky view to get signals from multiple satellites at the same time. But a stationary receiver that can take a while to get its position fix and then only needs to see 1 satellite now and then to maintain its time fix can get away with a far more obstructed sky view.

This application will work just fine if the position fix is off by multiple kilometers and many minutes.

-Jon
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It would help if you could train the module on position in open air then move it with non-volatile position and just occasional time updates.

My understanding of the GPS process is that even if known to be completely stationary a GPS receiver needs at least two satellites in its field at the same time.
If not known to be stationary and therefore able to use a non-standard algorithm, the constellation must include at least 3 satellites.
Additional satellites beyond that potentially narrow the circle of confusion.
 
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H

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
winnie said:
I have not used the product but have used quite a bit of GPS hardware at a low level. My strong guess is that this unit will likely work just fine if it can see _some_ sky with minimal interference.

If you need an accurate position fix that updates frequently, then need a good unobstructed sky view to get signals from multiple satellites at the same time. But a stationary receiver that can take a while to get its position fix and then only needs to see 1 satellite now and then to maintain its time fix can get away with a far more obstructed sky view.

This application will work just fine if the position fix is off by multiple kilometers and many minutes.

-Jon
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No sky, inside concrete encased room at bottom level of parking deck. Looking to see if customer will allow piping it outside.
 
Flicker Index

Flicker Index

Senior Member
Location
Pac NW
Occupation
Lights
spark master said:
The best ones are at the Home Depot. Easy to program. The supply house ones loose time, impossible to program, etc, etc.
I have 4 at my house. 2 Home Depot, and 2 supply house. The 2 supply house ones area always 10 minutes apart, no matter how often I correct them.
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I've yet to find one that is setup to "preserve current state". Meaning that if the power is on and there is a brief outage, revert to "on" after outage, and if it is off, remain. The ones I am familiar with will turn off after an outage and remains off until next scheduled power on.
 
S

SSDriver

Senior Member
Location
California
Occupation
Electrician
Flicker Index said:
I've yet to find one that is setup to "preserve current state". Meaning that if the power is on and there is a brief outage, revert to "on" after outage, and if it is off, remain. The ones I am familiar with will turn off after an outage and remains off until next scheduled power on.
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The GPS timer one reverts to ON when When power is restored until it connects with the satellite. Then it will resume whatever the schedule is supposed to be at. I was actually really happy when I 1st figured that out.

Edit: I should add it is not a full blown timer. It is a dusk to dawn control. So it will revert back to dust to dawn after it makes satellite connection.
 
O

oldsparky52

Senior Member
Location
Wilmington, NC USA
W

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
The GPS timer folk have an interesting model.

The units are specifically sold as programmed from the manufacturer, and you can't change the program. They will set it up to do any dance you want, but that dance is then set in stone.

No possibility of random Joe mucking with things and messing them up, but no way to change if needed (I guess other than sending it back to the manufacturer).

Jon
 
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