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Comment by geerlingguy | Hacker News Reader

I don't believe it's necessary to have multiple GPS antennas (one per device), unless signal path redundancy is required. A good GPS distribution box like from Time Machines or GPS Source can split the antenna signal to many devices without an issue.

A signal distribution box used from eBay is a lot cheaper than a good outdoor GPS antenna!

Though if you have enough cable and enough antennas already, no harm in having a little array like in OP.

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>I don't believe it's necessary to have multiple GPS antennas (one per device), unless signal path redundancy is required

Don't those splitters typically have an amplifier, so become a single point of failure?

If you're going through the trouble to have multiple time servers on your network, you probably want to make sure that an amplifier failure doesn't take them all down at the same time.

The antenna has an amplifier, usually with more than enough gain to support downstream splitting. But then sure the antenna is a SPOF.

Also the splitter will pass through the dc-bias on the first port to power the antenna, -- so whatever is hooked there is another spof.

GPS antennas typically need power. GPS receivers expect to be the sole power supplier. Simple, cheap signal distribution won't handle this. There are splitters that can allow one downstream port to supply power, but that fails when that single receiver fails. There are other splitters that are active-active. I guess you're claiming that the boxes from Time Machines are such active-active devices.

Those are not cheaper than an antenna! Although from the photo I'm not sure he bought the cheap antennas.

Speaking from experience deploying stratum-1. Not stratum-0, but the same GPS concerns.

Depending on your application a GPSDO may well be the entirely wrong solution depending on lots of implementation details.

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