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imseanbrown
Premium
join:2005-12-20
New York, NY

802.11a Repeater Site

Greetings everyone -- I haven't posted in a while... I'm getting around to posting a lot of my projects... enjoy this one...

802.11a Repeater site a'top 700' Building
»www.sleepyshark.com/projects/802···er-site/
--
Thanks,
Sean Brown
»www.sleepyshark.com

voxframe

join:2010-08-02
Those antennas are way too close to each other.

I work with Ubnt gear 24/7 and can tell you, you'll be eating self interference even if you're on separate channels.

Normal spacing is essentially as far as you can go to separate the antennas both vertically and horizontally.

By my guess, you're going to cut everything you're doing by more than half it's capacity with that setup. Possibly more. All depends when you load it up. If you're trying to replace a synchronous circuit of some kind, you're gonna feel it at some point.

3 Options that will gain you practically double your throughput and stability.

1 - Separate the antennas, bigtime. You should be looking at 5 feet vertical and horizontal, each. This doesn't look possible in this situation, so I'm not sure what you're gonna do about that. Maybe separate mounting?

2 - Shielding. This is not the god-solution here. But it'll give a lot of help. Look up a company called RF-Armor. They won't help with those Nanos though. But it will give a decent improvement with the sectors.

3 - GPS. Again this won't help the nanos. But at least you can sync the sectors so they won't piss all over each other. You'll lose throughput, but gain stability.

Ouch... I'm not sure what your wireless experience is, but yeah that's pretty scary right there. I don't mean to harp on you either, but you're going to have problems with that mess at some point. The more you load it, the worse it will behave. Another issue with everything being that close is it will "deafen" the radios. Imagine having 6 idiots all standing back to back in a circle with huge blow-horns going all day. With no separation or shielding or talk control, someone is going to become deaf soon enough.

What are your signals looking like? If you've got anything that sees anything at a signal stronger than -50, you're going to be most likely damaging stuff at some point.

voxframe

join:2010-08-02
reply to imseanbrown
EDIT - Quick edit, noticed you do have GPS. Good, this will help if configured right. Sorry didn't see that just yet.

How is the 2.4 spectrum up there? I can't fathom mounting a thing in 2.4 any more due to interference... And I'm fairly in the boonies.


DarkLogix
Texan and Proud
Premium
join:2008-10-23
Baytown, TX
kudos:3
why are you mentioning 2.4? he's using 5GHz.

voxframe

join:2010-08-02
reply to imseanbrown
In his equipment list it says
Ubiquiti Airmax NanoStationM2 with 802.3AF PoE injector (secondary backhaul)

So that's 2.4 (I had originally assumed it was all in 5.8 as well... Which would have been even worse for self-interference)

imseanbrown
Premium
join:2005-12-20
New York, NY
reply to voxframe
Love this post... all the things I have concerns with, so i'll address individually:

1. Antenna separation was originally proposed, but due to the existing RF and lack of mount points (where we needed it) we were forced to use one mount point.

Side note: this site is extremely "unique" - they're driven by aesthetics and not functionality (nor revenue for that matter). They do not allow for stand-offs or A-frames for separation at a mount point - everything MUST look "minimalist" from the ground-level. Hence why you ONLY see omni antennas at this site - it is not friendly for what we are doing.

2. We have the shields - oddly I have no pictures of them installed, but they are there.

Thankfully this site serves the dense metro area and we are not "swinging for the fences" looking for a 6 mile shot from this site - that being said, we've already drastically backed down the TX power enough to minimize (as best we could) cross-talk and interference between equipment.

Our other sites (typically roof-mounted) alware get 90 degree sectors mounted to corners of buildings to give the spacial separation that RF likes
--
Thanks,
Sean Brown
»www.sleepyshark.com

imseanbrown
Premium
join:2005-12-20
New York, NY
reply to voxframe
3.65 is what we're using for backhaul and does extremely well since we're only going 0.2mi - The 2.4 is used as a backup in LaCP in case of any side of the either link going down.

voxframe

join:2010-08-02

1 recommendation

reply to imseanbrown
Ahhh now I feel a lot better.

And to add in... God damn I hate those "Make it pretty" installations with no budget but high functionality requirements.

imseanbrown
Premium
join:2005-12-20
New York, NY
Yeah, our main focus of this site it to serve west - our main site (while 20 stories) is blocked by MANY higher buidings west facing - this this 40+ story building will be used to light the people in the RF shadows

themagicone

join:2003-08-13
Osseo, MN
reply to imseanbrown
That is the area I want to get into more. Love working on RF/Backhauls but without a strong background other than numerous certs and a Masters, it is very hard. Good work.


TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5
reply to imseanbrown
said by imseanbrown:

they're driven by aesthetics

One wonders why they even care, when 99.999999999999999% of the population will never even see it, and its not like its some tourist attraction where everyone wants to go.

Even for those that can see it ... its the roof of a building for crying out loud.

facepalm