Editing MayFirst2012NYCCrateDeployment (section)

= Equipment =
{|
| [[File:Prepacked_crate.JPG|thumb|x300px|alt=Pre-deployment crate photo|Crate and equipment pre-deployment. Repeater is on the right in a ziplock bag.]]
| [[File:Packed_crate.JPG|thumb|x300px|alt=Mid-deployment crate photo|Better photo of crate internals.]]
|}

=== Basestation Crate ===

* Rolling Pelican Suitcase/Crate
* 1x 5GHz Ubiquity [[NanoStation]] ("N5")
* 1x 2.4GHz Ubiquity [[NanoStation]] ("N2")
* Intel Atom x86 router (running pfSense)
* Ethernet switch
* 12v sealed lead-acid battery (absorbed glass mat)
* 120v AC inverter and power strip

The basestation/crate was pretty heavy with the battery; care was taken to make
sure the battery wouldn't rattle too much, everything was secured with
adhesive-backed velcro to the inside of the case. Lifting the case up and down
stairs we a bit of a pain, but it was easy to roll, and only suffered a bit of
wear being rolled more than a mile over endless curbs, potholes, and
cobblestones. 

[[File:Crate_electrical_diagram.svg|frame|center|alt=Electrical Block Diagram|Crate Electronics Block Diagram]]

Total crate electrical draw coming out of the inverter (as measured with a
Kill-a-Watt device) was about 25 watts idle. We chose to use a lead-acid
battery because they are simple and (relatively) easily available.
Unfortunately they are very large and heavy (for the desired capacity),
somewhat dangerous (high current), and more expensive for the sealed "absorbed
glass mat" (AGM) style required for safety. Regular car batteries have sloshing
liquid acid and should not be left at an angle, can leak or spray acid, are
damaged by deep discharges, and are generally unsafe for mobile deployment
(though they do have large capacity and are cheap if found used; might be
appropriate for towers neading DIY large capacity battery backup). AGM
batteries cost around $100 for the capacity needed and can be found at marine
supply stores or in the marine/recreation section of car supply stores. We got
a smallish AGM battery new from AutoZone (was able to return it a week later)
which had a 19 amp-hour capacity. Large batteries usually don't list an
amp-hour capacity, they list "Reserve Capacity" (RC); in our case we wanted at
least an RC of 40 (messy units, see wikipedia). 

No special efforts were taken to reduce power consumption via software settings
("sleep modes").

[[File:Crate_network_diagram.svg|frame|center|alt=Network Block Diagram|Crate Network Block Diagram]]

Above is the network structure block diagram. The nanostations operate as
"dumb" radios, all DHCP is handled by the central router.

The 2.4GHz [[Nanostation]] was configured to only use 802.11bg (not 802.11n), on
the wild guess that high throughput speeds would be an impossibility and that
sticking to the older protocols supported by all devices would reduce
complexity.

Otherwise the router and NanoStations were configured the same way as a regular
[[FreedomTower]], see documentation elsewhere.

[[File:NanoM2_DS_beamshapes.png|thumb|600px|center|alt=NanoStation Beam Shape|NanoStation Beam Shape, from [http://www.ubnt.com/downloads/nanoM5_DS.pdf datasheet]]]

The above diagram (from NanoStation documentation) shows the expected RF signal
strength. The radios were mounted to the front of the case facing forward
vertically, such such that the bubble of WiFi coverage was directed forwards as
if the case was a large speaker. The "squashed cone" of coverage was about 50
degrees "wide" and 30 degrees "tall" according to the above diagram. 

Obviously the overall functionality of the basestation could be replicated with
a tiny cheap off-the-shelf battery powered WiFi hotspot and a 4G USB dongle.
Our equipment and software was much higher performance, but if we wanted to
scale out this kind of deployment the package size could be reduced
significantly.

=== Repeater ===

The motivation for the repeater was to test extended range using the
(relatively clean and reliable) 5GHz band as backhaul and making shorter-hop
2.4GHz connections to users with 2.4GHz-only devices.

Equipment:

* Netgear WNDR2700v2 ("N600") WiFi gateway/router running OpenWRT
* Small sealed lead-acid battery (12v)

The battery was connected directly (with a fuse inline) to the router's barrel
jack power connector by canibalizing the wall-wart cabling; this router takes
12v DC input, so not conversion was necessary. The router pulled 6-11watts of
AC power (measured with Kill-a-Watt).  No special software efforts were taken
to reduce power consumption.

The router was configured to use the 5GHz radio as uplink (WAN) and to provide
general connectivity via the 2.4GHz radio (LAN), with mostly default settings.
This means the router ran an internal DHCP server (dnsmasq?) and handled all
aspects of client configuration locally, instead of forwarding request packets
on to the primary router in the basestation. A seperate SSID ("The Free Network
Repeater") was used.