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Re: [TowerTalk] lightning protection fiber optics

To: towertalk@contesting.com
Subject: Re: [TowerTalk] lightning protection fiber optics
From: Jim Lux <jimlux@earthlink.net>
Date: Wed, 10 Jul 2013 07:22:05 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
On 7/9/13 10:26 PM, Spencer wrote:
Talk to the people at the VLA in New Mexico. They have 27 dishes with FO
cables. They have a pretty good idea on how its done.


That they do, but based on what I know they do at the Deep Space Network, and what we do for testing at JPL, that kind of FO interconnect is different than a run-of-the-mill network interconnection. The fibers may be the same kind, in general, but what's carried over them, and the supporting equipment is very different.

For instance, at DSN, they worry a LOT about time delay through the cables (for arraying multiple antennas and interferometry) and run them in temperature monitored and controlled conduits. They also run the RF through the cables using fairly high dollar transmitters and receivers. For instance, there's spigots for a 100 MHz signal from the Hydrogen Maser in the labs downstairs from my office that are carried optically. Ortel/EMCORE is a big name in that business.


This stuff is actually pretty cool. RF in at one end, and RF comes out at the other end, a few km away. And, it's been around long enough so that it might be showing up surplus.

These things use singlemode 9/125 fiber, since wide bandwidth is really important.
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