[time-nuts] Lightning strikes vs GPS antennas

jimlux jimlux at earthlink.net
Sun Jul 4 16:46:55 UTC 2010


Michael Baker wrote:
> Time-Nutters--
> 
> The 5-year Flash Density Map of the USA provided by
> the National Weather Service indicates that my county
> here in N. Central Florida experiences "16 and up"
> strikes/sq-km/year.
> 
> < http://www.weather.gov/os/lightning/images/map.pdf >
> 
> Experience bears this out...
> 
> I live on 6 heavily wooded acres and have had at least
> 6 trees struck and killed somewhere on my property
> over the last several years.
> 
> I make it a faithful practice to disconnect antennas
> from any gear during the frequent thunderstorms we
> experience.
> 
> I have considered fastening a GPS antenna on the end of
> a 12 foot fiberglass pole and installing it in the top
> of one of the trees next to my workshop building so that
> it has a clear 360 deg sky view down to within a few
> degrees of the horizon.
> 
> It would be nice to come up with some way to use fiber
> optics to isolate the GPS antenna from the receiver.
> Coming up with a solar panel and battery to isolate the
> antenna and RF preamp power is no big deal but coming up
> with a way to isolate the RF via fiber is more problematic.
> 


I suspect what you're looking for is a *inexpensive* way to do this..

Fiber optic links for RF are an off the shelf thing.
Miteq or Ortel (among many others) have them..

You can also buy off the shelf fiber links optimized for GPS.

Typically, you send DC to the head end (or your solar panel/battery 
idea).. The actual receiver is on the ground.

Although, with inexpensive GPS receivers, you could put the receiver up 
there and just send the 1pps and serial data down the fiber.



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