muni WiFi antenna on lightpole

here is a local muni WiFi lightpole antenna for Naperville, IL.

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wonder what the metal pole smack in the middle between the antennas does for the RF radiation pattern ?

any ideas on the hardware vendor of the AP ?

Reply to
P.Schuman
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IL.http://www.naperville.il.us/emplibrary/transmitter-sm.jpg>

Negligible antenna pattern distortion. The mast is at right angles and looks about 3" away from the antennas.

Reply to
nevtxjustin

"P.Schuman" hath wroth:

MetroFi mostly uses Skypilot hardware. See:

No clue on the exact model number. You should be able to see the serial number tag from the ground.

There's no effect on coverage due to the pipe. That's because the antennas are inside the upper inverted bucket and not the two drooping antennas, which are for the backhaul. See cutaway view at:

Note that this is a steerable antenna system which works on point to point rules instead of point to multipoint. That means they can belch up to 28 watts EIRP instead of the usual 4 watts EIRP. See some detail at bottom of:

In my never humble opinion, this sucks as it creates an alligator (big mouth, small ears) which is an access point that has much more transmit range than receive range.

Reply to
Jeff Liebermann

tnx for all the info & links...

"alligator" - yeah, many years ago our 2m repeater was tagged with that..

250watts out at 900' - downtown Chicago - WA9ORC - then we added our remote receiver voting system....

Phil - WA9TKA

Reply to
P.Schuman

It was interesting reading thru the various product pages. Wonder if anyone else is using the cellular antenna "sector" concept for WiFi ? We have it here for our Motorola Canopy wireless W-ISP system.

The 28w EIRP is for the backhaul in the 4.9-5.4 range... so the "A" band would be impacted.

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Noticed that receiver is mentioned as -90dbm @ 6mbps How does that compare to what I remember as something like

20db quieting @ .4uv sensitivity.
Reply to
P.Schuman

Please read the articles again. Skypilot is NOT a sector approach. Sectors systems, such as Canopy, assume one radio per sector. Skypilot uses a *steerable* antenna system, where one radio can select a variety of antennas, pointed around the compass circle. That's quite different in the bloodshot eyes of the FCC. Sectors to no in themselves reduce interference with other users. Steerable antenna systems will reduce interference as they can simultaneously increase gain in the desired directions, while inserting nulls and holes in the directions of interference.

Sure. One mutation of the proposed 802.11n standard is to have steerable antennas, which somehow equates to being MIMO. Ruckus Wireless is the major chipset vendor, which is used in all manner of home wireless access points.

That's just one of their models. These days, all the mesh vendors are going after the Homeland Security money, and building mesh radios that include the 4.9GHz band. The 5.4 to 5.7Ghz 802.11a band is more in line with what a WISP might be using.

Argh. Forget everything you know about ham and commercial land mobile FM measurement techniques. You can't compare analog and digital senstivity measurements. 20dB quieting is miserable reference for digital data because there's no audio output to measure. Instead, we measure BER (bit error rate) or PER (packet error rate). There are standards for measurement in the 802.11/b/g specs. The usual reference levels are 1*10^-5 BER, 1*10^-6 BER, 8% PER, or 10% PER depending on speed and regulatory authority. I made a graph of the some published and measured specifications. Note that everyone lies:

Details if you want, but methinks some reading on digital radio preformance measurements might be in order first.

Reply to
Jeff Liebermann

"P.Schuman" hath wroth:

Here's another steerable antenna vendor which doesn't really mention much about their technology on their web pile:

"Vivato's base stations use phased-array smart antennas to create highly directed, narrow beams of transmission." The data sheet for their base stations show over 40dBi EIRP instead of the point to multipoint 36dBi maximum.

Reply to
Jeff Liebermann

Vaporware usually doesn't really mention much about the technology behind it.

snipped from

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29, 2004

[Vivato employees] have been warned to keep their resumes tuned up because the company is not sure its going to be around much longer. They are selling their units at a loss, even at the bizarrely high price they go for. The cost to build each of the units meets or exceeds the sale price, which is definitely a harbinger of death for any company. There is no real secret that the company is money starved, having quickly burned through the $64 mil they got last year in 2nd round funding.

Vivato is building a lesser model of the one approved by the FCC. Now boasting only 20 radio/antenna pairs, it isn't the device that it was cracked up to be. Where the prototypes played pretty nicely with other users of the frequency, these fellas are simply high powered foghorns

--and the same exact job they do could be done with much less expensive equipment without losing a bit of utility. That assumes that other equipment would be permitted to blast out a 52dB signal as the Vivatos are waivered to do.

Reply to
nevtxjustin

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15, 2005 Vivato Ceases Operations

Vivato has ceased operations according to a company spokesperson: I confirmed via a spokesperson Thursday night that early enterprise wireless switch maker Vivato has shut down.

Reply to
nevtxjustin

snipped-for-privacy@gmail.com hath wroth:

Yep. They went under and then floated back to the surface with investments starting in June 2006. See timeline at:

I just mentioned Vivato as an example of another of the steerable antenna system vendors.

Reply to
Jeff Liebermann

snipped-for-privacy@gmail.com hath wroth:

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June 29, 2004

Jim Thompson has some comments on that article:

I'm not sure, but methinks that Thompson and Stroh fail to appreciate each other. Strohs reply does some backpedalling and hair splitting.

At this point, it's NBC (NoBody Cares).

Drifting slightly...

Here's one unit that has 12ea 802.11a and 4ea 802.11b radios in one access point:

Only $12,000 ea. Sorta support 1000 users if we put most of them to

5.7GHz (802.11a):

Built in RADIUS server with about a 200 user limit. I'm not thrilled with the way they simulated 1000 users (using 1000 802.1x authentications). That doesn't simulate mutual RF interference and over the air timing problems.

Reply to
Jeff Liebermann

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