Internet in the Observatory
Posted 07 July 2014 - 01:02 AM
The traditional design standard for fiber is a bend radius of 15 times the diameter of the cable while under installation pulling stresses and 10 times after installation. 600 pounds is the typical max pulling tension.
Communications conduit standards call for no more than 180 degrees of bend between pulling locations. This helps reduce the pulling tension required to place the cable in the conduit. I wouldn't use less than a 2 inch diameter conduit to accommodate the pre terminated fiber pulling eye. All turns should be sweep radiuses, not small radius elbows that some electricians use.
If you don't want to place a conduit you can use highly directional wireless device or pair to connect back to your house wireless access point. I recently purchased a Ubiquiti NanoStation loco M2 to pair with a WAP in my astronomy trailer. The Nanostation is mounted on a mast on the outside of my trailer and is powered by POE from a wireless access point inside my trailer providing my local network on a different wireless channel. This setup provide strong local wireless with the Nanostation giving me a strong direction signal to a distant wireless connection. Using pairs of the Nanostations you can go over 1000 feet line of site.
Posted 07 July 2014 - 09:57 AM
We get decent throughput with these (generally about 6-9Mbps down, 2-4 up) over distances averaging about 2/3 of a mile from transmitter to client. I would think that 200 feet would be a cakewalk.
Posted 07 July 2014 - 10:08 AM
My own CPE (customer premises equipment) is a TP-Link TL-WA5210G that sells for about $60. It has both AP and client bridge modes, so one could be set up as an AP near your Internet source, and another as the client at your observatory. Indeed, I just noticed that the top review for this product on Amazon is from someone using it to feed an observatory 600 feet from home. He found that the signal in AP mode was strong enough to pick up directly with computer wireless adapters, so there was no need for the client unit.
That's the one I use too (linked in my note above). I'm about 300' from the house and have a very strong signal - better than in some places inside the house! I walked away from my house with my laptop and got over 1000' feet away before I could no longer connect. That's with a single unit, and through trees and shrubs. With 2 units, one at each end, you could go a lot further.
Posted 07 July 2014 - 05:29 PM
I'm the original poster, and appreciate all of the excellent suggestions.
Do you have mains (AC) power in your observatory? And if so, is the main breaker somewhere in your house/garage?
My solution for the same problem (and similar distance) you're faced with was to install a pair of those 'ethernet extenders' which can make use of mains wiring. I was suspicious at first as to whether or not it would work (my total run is probably nearer 300 feet), but it does and it works like a champ.
Posted 07 July 2014 - 05:45 PM
If you can lay fiber with media converters, that is by far the best solution but also the most expensive. Laying Ethernet cable is not much cheaper than fiber but raises the issue of lightning ground strikes as described above.
If you are looking to only link limited devices, and do not require 100% uptime 24/7, and are willing to accept the possibility of unwanted snooping, I would follow the advice of those above who suggest a wireless bridge. Relatively cheap (no trenching) and a great "circuit breaker" in case of a ground strike.
BTW, I have used ALL of these techniques so this reflects actual experience. My guess is that you will end up with a wireless bridge.
Posted 07 July 2014 - 10:24 PM
Be aware that any antenna protruding from an observatory can be an entry point for lightning and lightning damage. There are lightning shunt devices available (like Polyphasers) that are designed to shunt lightning energy to ground and keep it outside of the observatory.
Posted 08 July 2014 - 12:20 PM
Posted 19 July 2014 - 06:55 PM
This is a quick followup to my efforts to get wifi to the OBS computer.
I used the NetGear Extender WN3000RP, and after setup mounted it on my back porch. This faced the OBS at about 100ft. away, through trees. And it produced a nice strong signal inside the observatory.
Setup was an experience and took several tries to get it right (their instructions need rewriting). But all appears well now.
Thanks again for all of your advice. I genuinely appreciate it.
Posted 20 July 2014 - 01:04 AM
Posted 21 July 2014 - 07:39 AM
With just a little research, I found the NetGear N600 WiFi DB USB adapter. This one was very easy to install and worked well with the NetGear extender.