So Cal Free Net.org

Drew, Seren, Jason and Michael did a site survey today at Golden Villa affordable housing apartments. Here's the report.

Results Summary

Two access points mounted at each end of the L shaped layout should be sufficient to provide adequate coverage throughout the complex. The buildings are 2 story with 4 units per building and attenuate the signal markedly. However the proposed AP layout allows most units in the buildings to receive a direct signal.

For equipment, we could either go our usual route and have a main AP with both 802.11a and 802.11b radios and a second AP relaying from there. Total cost approx $1300.

Alternatively, we could use a WDS-based solution either based on an inside AP-160 and two Sputnik AP 200 or the Netgate HS3000 (both about $900).

In addition, in the main office we'd either place an embedded PC running m0n0wall or a Sputnik 160 is possible if we go the WDS route.

In short, we could build a system for all 44 occupants and the computer lab for $1000 - $1500.

We saw 4-5 APs during out site survey - much fewer than normal.

Layout Details

The buildings form a rough L shape, with the office located on the leg of the L but towards the corner. It is wrapped around a road on the inside of the L with a gorge on the outside all around. Single dwelling houses are on the opposite side of the road.

The office has an existing Cox business cable connection and is the rooftop we used to place the test equipment (there are also 4 apartments in the building). The test AP was a 200mW Senao CB3 plus, http://www.wlanparts.com/product/NL2611CB3PLUS, with an 8.5 dBi 10 degree downtilt antenna, http://www.superpass.com/SPDG6O-D10.html. Right opposite the office is a community building where they plan to create a small computer lab.

Testing details

With three laptops containing various combinations of built-in (Centrino) and external cards (30mW Atheros-based Netgear and 50mw? D-Link non-prism) we walked around all the buildings while running a continuous 1500 byte ping to the AP. When the pings started dropping we marked that as the edge of useful range.

Using this criteria, we determined that over half the buildings could be covered with one AP. Two remaining buildings had incomplete coverage. Some of those apartments could get good coverage from their front windows, but not beyond. Assuming the same propagation, we concluded that another AP mounted on the last roof of the tip of the L, but closer to the L corner would provide the whole complex with good coverage. The houses across the road on the inside of the L would also get good coverage, and likely the houses across the gorge (though there weren't many, and the downtilt makes it less likely).

Mounting details

None of the rooftops are flat. We decided that mounting a standard L shaped bracket like that used for satellite dishes on the end of the building at the peak of the roof would be simple and effective and allow the antenna to rise about 1 foot above the roofline. We could route outdoor Cat-5 cable to the roof via the water downpipes which are open at the bottom and then up to the box following side roof trim panels. A tall ladder will be needed for the installation day.

At the office location we will need to drill through the office walls like cable TV installers do. Inside will be power and the internet feed.

At the other building location the power box has a double outlet underneath the main meter box (5 meters - 4 units plus 'house'). We would need to add a water-resistant housing for the PoE. A simple 4x4x4 electrical box would suffice and could be mounted directly on the wall (perhaps even surrounding the double outlet box?).

Dirt surrounds all buildings so driving a grounding rod for lightning protection should be straight forward.

Pricing details

Standard relay:

$ 40      - 2 x LMR-400 N-male N-male cables
$ 20      - lightning arrestor
$ 45      - PoE
$ 65      - downtilt 8.5 dBi omni
$ 50      - 802.11a 'backfire' antenna
$ 14      - U.FL pigtail
$ 70      - 802.11a radio
$320      - Metrix kit (with 200mW 802.11b radio)
$ 20      - misc fittings (copper, cat-5, hose clamps)
------
~$650 each radio

Sputnik based:

$ 20      - 1 x LMR-400 N-male N-male cables
$ 20      - lightning arrestor
$ 45      - PoE
$ 65      - downtilt 8.5 dBi omni
$290      - www.sputnik.com/products/aps/ap200.html
$ 20      - misc futtings
-----
~$460      - includes tax on sputnik

Netgate HS3000 based:

$ 20      - lightning arrestor
$ 65      - downtilt 8.5 dBi omni
$355      - www.netgate.com/product_info.php?products_id=41
----
~$440     - 250mW HS3000 comes with lots of odds/ends

Base Station Options

Sputnik 160 (WDS only)
~$110 - with tax and ship

M0n0wall based Nokia IP110

$100  - Nokia IP110 from Ebay ???
$ 20  - HD to CF adapter (mini-box)
----
$130  - with ship - very approx!

M0n0wall based Soekris:

$161  - net4501 with case
$  9  - power supply
$  10 - CF card
----
~$190 - includes tax

This started out being short but ended up pretty complete. Please ask any questions about anything that isn't clear.

If we can get the go ahead fairly quickly, we could schedule this installation quite soon. This will be a very worthwhile addition to this community as well as a great wireless learning experience for everyone, so I hope to see a few new faces on install day :-) .