On Friday 24 April 2015 00:50:23 Gregg Eshelman wrote: > On 4/23/2015 10:52 AM, Bruce Layne wrote: > > Gene - Consider getting some Ethernet cable that's direct burial > > rated for underground use and burying it a few inches for the run to > > your shop. It'll not only be resistant to sun fading and high > > winds, but also nearby lightning strikes. > > Reminds me of when a friend of mine worked in internal IT support for > Albertson's. At one of their locations with a gas station across the > parking lot from the grocery store, they'd periodically get a > lightning strike right in the middle of the lot and it'd fry various > pieces of equipment. > > They had an ethernet cable in (I assume non-metallic) conduit under > the parking lot, connecting the gas station to the server in the > store. > > Lightning quit hitting there after the copper wire was swapped for > fiber optic. > And that makes purfect sense. But the cost of the optical stuff is a hard sell. The cable isn't that much higher priced, but the joints, and a splicer to make them put it out of range unless you know some one at the cable/phone company who can do that work.
For a 50 foot run for me, I think I'd be tempted to go for line of sight lasers aimed at each other, but I haven't priced video speed laser stuff in yonks. Anybody else? The pringles can antennas for a wifi circuit might also be usable. Theres a million ways to do it. Gunn diodes in a little 12" diamater dish, running in the 23Ghz band can be 1 degree aim accurate, with their 60 milliwatts of power good for quite a few miles if you can get them up on a tower for line of sight. Good for a 10 megabaud digital circuit. Heck, lots of people have the bare "dish" dish left over from that grand experiment in bad weather failure, and a pringle can antenna at the focal point of one of those, aimed at its twin on the other end ought to get you several hundred yards worth of a bulletptoof circuit. With decent attention to the mechanics, using cross polarization (vertical one way, horizontal back over the same path) could double the range. Even without that, the latency as it switches from transmit to receive every few milliseconds, it ought to be good enough for most of what we do that isn't realtime or somebody is dead stuff. This could be done between two routers just by housing it to keep the weather out of it, and replacing its rubber duckies with the pringle can antenna. Just make sure the "can" is capped (plastic, like solid pvc) to keep bees from thinking its home. Several years ago, a couple hams made the pringles cans work at 26 miles. But while its quick and dirty, the friendly candy company takes a dim view because the beam width is 15 to 20 degrees wide, and they have specs on that stuff down to about a 3 degree requirement to hold down interference with other services in those bands. 2 degrees for satellite dishes that can uplink. Lots of ways to get around the long wire being an EMP antenna, but the long wire, or the fibre, is the only two ways that doesn't need regulatory approval. And fibre is not an EMP antenna. Signal losses when well spliced are very nominal. We put in a 4 channel lashup 15 years ago so we could feed the local cable companies head end straight out of the switcher, about 8K$ for each optical box about the same size as a home wifi router. Cable brought in the fibre and when when it was all up and running, they measured the loss from our studio building to their head end, 39 kilometers of fibre between them, 1/2 a db of optical loss. The cable guys said that was nominal for what they were doing if the splicer was well calibrated and making good joints. Ranging far and wide of the topic, but that is whats available if we think plumb outside the box. For my runs, (there is actually 2 because one of the switch ports in the shop feeds back down the hill to the garage, so I can have a machine in there too) a long chunk of cat5 hasn't been tapped hard enough to hurt anything. There is likely a first time I'll get tapped, but its not happened yet in several years. ;-) Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
