Make 2.4GHz parabolic mesh dishes from cheap but sturdy Chinese cookware scoops & a USB WiFi adaptor! The largest so called "WIFRY" or "WOKTENNA" (12"= 300mm diam) shows 12-15dB gain (enough for a LOS range extension to 3-5km),costs ~US$5 & comes with a user friendly bamboo handle that suits WLAN fieldwork- if you can handle the curious stares! Neater boutique versions may better appeal indoors. NB-unless you use more powerful USB adapters (such as ALFA & Senao offerings mentioned below),weak USB adapter output power may mean you now hear more stronger APs than you can link back to ...
DIY antenna details best followed from pix -click on a thumbnail for full size (800 x 600) images. BUT -short on reading time? Documenting lab notes & links too dry? Need WLAN access pronto? No Asian cookware? Check fast track INSTRUCTABLES such as our Poor Man's WiFi or the associated sieve ,steamer or scoop inspired spin offs instead!
NB-the phrase "Poor Man" is not usually considered insulting, but indicates (possibly with a degree of DIY pride) a desire to "make it do, use it up, wear it out" while laterally solving a problem. NZ Kiwi's are champions of such #8 wire ingenuity,with our electric fences a typical appropriate technology. Guess our project even has East meets West cross cultural aspects- in the style of Kiwi Fruit evolving from Chinese Gooseberries !? Lab note jottings below pix rather blog style,but arose during an educational WiFi workout & are intended to stimulate others into similar DIY investigation. The author- who first wrangled antenna as a radio ham in the 1960s- is a career educator with a flair for innovation, with extensive hands on WiFi experiences - www.manuka.orcon.net.nz has insights into "his" 2002 Lucent Orinoco PCMCIA driven Sardine Can Biquad antenna. LAB NOTES text below intended to document rather than entertain & enthuse- suggest you stay with images for the latter! 21 April 2004: The long awaited NetStumber 0.4 ( + PDA MiniStumb.) is just out ! ( www.netstumbler.com~1.2MB). Of course we've been trying all sorts of Wi-Fi cards to hand! Originally NS only favoured Orinoco PCMCIA, but the latest flavour IS talking to such cheapies as the popular NZ Dick Smith Electronics (DSE) NZ$69 USB thumb
dongle adaptor (cat XH6822). This DSE sweetie is based on a ZyDAS chipset,& seems to perform almost as well as esteemed Orinocos under XP. Yah! Can't say things look
bullet proof with NS 0.4 yet, but it's certainly a tempting way to go, since USB
cables & active extenders are dirt cheap,& being just digital are
lossless compared with COSTLY microwave coax cable & connectors. Will
maybe do a roof top "sweet spot" trial from here in central Wellington, New Zealand
& perhaps upload a NS file,but picked up a AP ~500m LOS away OK. 25th April 2004: Well - ANZAC day dawned fine here in Wellington (NZ), so in best military
tradition we ran a few LOS(Line Of Sight) scouting trials,supporting the
USB device on a broom handle tied to the roof,fed by ~5m of regular el
cheapo USB cable from an XP laptop running the new NS 0.4 inside.
As always LOS means just that at 2.4GHz, & assorted in line trees &
buildings caused massive signal losses, so ~100m was all we managed
while walking around the house/yard/street with a Dell Axim PDA & a
Socket low power CF WiFi card.
We'll give it a further trial tomorrow across the inner city Basin Reserve to
Mt.Vic, where a standby Orinoco Sardine can biquad easily handles
the 2km from work ( Massey University). Experiences however indicate already that such
simple food can reflectors at each end look only good for ~2km LOS, & this USB receiver doesn't seem as sensitive as an esteemed PCMCIA Orinoco. Sniff ! That USB adaptors
ceramic antenna may be the culprit - anyone fancy a "hack" &
installation of say a Biquad ?!
THOUGHT - fit this thumb at the focal point of a directive antenna?
Quick trials with NS 0.4 showed useful gain with even a bare metal
plate behind it. Perhaps the classic "Sardine can" biquad reflector?
Simple metallic plates behind the unit gave significant weak signal
boost, espec. when spacings were ~32mm ( which of course is 1/4
wavelength at 2.4GHz). With DIY dishes (each 15-20dB ?) then range
increases to say 5-10km may result - dB maths says each 6dB
gain will double the range.
The real attraction with USB of course is the jelly bean cheapness of
cable & connectors-we paid NZ$95 for just a 1/2m Orinoco pigtail in
2002 that eventually broke it's tiny connector! Grr... In contrast the entire box of tricks used here today came to ~NZ$75, & with a USB active extender (~NZ$30) cables could be run on
to the basement. With USB cables in place you can swap out the WiFi
unit for a golf ball web cam up there for an improved view too-
cheaper than moving house maybe ! USB cables are so cheap that they're almost worth cutting up as DC hookup wire - 5m USB 2.0 extension cables( the USB 1.0 limit) wholesale here for under $NZ4 each. Woops- broom handle still outside in the dark. Stay tuned... 26th April 2004: Rustled up a simple corner reflector
(folded aluminium)to good effect & NetStumbler 0.3/W98 Orinoco
detected OK ~1km LOS away. Gain of such quickee antenna typically 5-8dB,& a
simple open mesh dish (bird netting etc) will usually be MUCH better.
The eventual idea of course is to have a lowish profile antenna that
can be mounted inside something like an empty plastic blank CD "cake"
tin or bowl. Mmm-recall a movie where the hero linked to a satellite via a chopsticks supported homemade antenna! It might have some merit- what WAS that movie called? 28th April 2004: Update- predictions on use with a dish confirmed, since we noted a
(nameless!) AP some 8km LOS away when positioned at the focal point of
an old 600mm parabolic reflector (~21dB). Compared with the expense & lossy
cable runs of regular devices, this USB approach just COULDN'T be
easier. ~1/2dB loss per m is typical with microwave coax, with maybe another 1dB at each connector. A 10m cable hence may "cost" you 7dB of gain that spiffy roof dish provides... We'll try next some DIY smaller reflectors, with aluminium foil coated curved
plastic lamp shades ($2!) showing particular promise. Only downside seen so far is that the USB units run rather warm, although an
overnight soak test gave no hassles. Surely we're not the only ones evaluating these USB adaptors - any other feedback ? With their tiny size & bargain NZ$69 (~US$40) price
(plus jelly bean cheap lossless USB cable/fittings) they look a winner.
30th April 2004: Have contacted DSE (Aust.),who inform these XH6822 dongles are a NZ only item, & they've no plans to retail in OZ- yet! However they DO sell a similar USB
WiFi adaptor, the Spirit XH4268 @ A$59. Anyone had experience with
these? Can they use NS 0.4 ? 1st May 2004: Poor Man's WiFi ? You can thank an impromptu visit to a Chinese emporium for our latest variation- a 300mm diam mesh parabola (gain ~15dB ?) that
fits this USB dongle beautifully. It's based on a NZ$8 Chinese cook vat scoop c/w bamboo handle. Asian students here inform this classic Chinese cookware item is known as a "Spider Skimmer", & is usually made of brass rather than cheaper galvanised mesh. Sizes are 6", 8", 9", & largest 12" (300mm) as we used. Total setup B.O.M <$NZ80 (~US$50 ) & that
includes the ZyDAS ZD1201 WLAN adaptor, USB cable,& dish antenna with
environmentally friendly bamboo support handle. Field trials anyone ? 2nd May 2004: While in the Asian Emporium diverse other cookware was noted, much of it stainless steel. Customers gave sideways glances as assorted woks, lids and pans were measured up& focal points calculated! Although tempting, normal woks are of course TOO solid & have serious wind resistance - a major factor here in Wellington even when closely attended ! Have just hilltop trialled that spider skimmer mesh scoop & managed an AP 5km LOS away ( NS 0.4 showing -80dB ). The whole development suits "Poor Man's WiFi", since for ~NZ$100 (~US$60) one could have the works ! Being appropriate technology fans, it's envisaged such a setup could have immense appeal in less developed, rural areas or schools etc. Naturally USB connectors are easy to maintain too. 5th May 2004: Finishing off quest & prowling hardware stores for antenna supports & tripods. The very thing-a garden hose mender makes a PERFECT mount for the USB socket, & only modest mesh trimming needed. To allow USB cable placement hack saw an angled slice cut in the hose mender- the screw on rings will secure OK. The plug in adaptor even fits in the recess at just on the desired 94mm too when internal joiner plastic trimmed/drilled off. As a "just how far can USB cables go " trial today, we had 5 x 5m cheap USB 2.0 M-F extenders cobbled together for a 25m ( 75') run, for which the USB adaptor never missed a beat. Yah ! Visions of WLAN PC at ground level & USB adaptor/antenna in a tree top sweet spot arise. Well - why not ? There's been a similar but corporate Power Over Ethernet (POE) approach for some time of course.
EXTRA: US contacts inform Texan outlet =>www.axiontech.com sells for ~US$25, this exact ZyDAS adaptor as a ZONET ZEW2000C. Apparently NZ outlet Computer Dynamics also sell a similar EDIMAX WL7117U (ZyDAS) unit ~NZ$65,but have not tried. At these prices a user group could buy a box & sell them at a modest profit while still in stock!? 7th May 2004: Phew- we spoke too soon- is this ever a fast moving field. Dick Smith NZ inform this XH6822 adaptor, after a store life of only months, is about to be replaced by a similar ZyDAS (cheaper ?)XH6859, & that a faster 54MHz IEEE 802.11"g" USB unit (cat XH8227) is on the horizon, but at ~twice the "b" price. With antenna such as we've developed, simply swap out the old & insert the new units as they arrive (or you can afford them !) With 54 Mbps "g" being so rapidly adopted, 11Mbps "b" hardware may become almost free to a good home. 11Mbps is naturally MORE than enough for many users, since even if only 1Mbps achieved with weak links & USB decoding overheads,it's still equiv. to ~20 times the speed of a wired dial up connection, & thus suitable for streaming video/Internet sharing/voice traffic/games/Netmeeting or even impromptu event/sports day/emergency WLANs etc. 19th May 2004: Sacre Bleu- this DIY Kiwi WiFi idea seems to have struck a worldwide chord, since ~10,000 hits in a week & numerous global links & citations. French,Spanish & even Polish mentions are "readable", but the Hindi version, while most exotic, defies our translation! Site overhaul needed, with proper DIY instructions instead of lab notes? Thoughts? 25th May 2004: In spite of wind susceptibility & carrying weight, pressed steel parabolic woks have also emerged as suitable homemade WiFi dishes. Woks sell cheaply & are easily drilled/chassis nibbled for mount holes. Gains ~17dB reported from a North Otago (NZ) user-enough to use an AP 4km away. Having come this far we may as well explore other suitable dishes-cooling fan mesh screens & even umbrellas have caught our eye.Publicity from yesterdays Dominion Post Infotech article shows NZ interest is keen, with schools especially enthusiastic-one had bare APs with just 50m LOS range... Yikes! 27th May 2004: Gadzooks-SlashDotted! Our humble WiFi lab notes went ballistic following a SlashDot mention,with ~43,000 global hits yesterday afternoon. Amazingly the Orcon server & Extreme tracker survived,even at hit rates ~200 a minute. To those who emailed & have yet to get a reply- responses have near swamped us,so please follow DIY instructions-shown as text notes on many pix- while we consider a site rewrite( perhaps a Wiki ?)! Several mirror sites now exist too (US & France). As a tribute to the democracy & efficiency of the Internet, "old conference junkie" Stan reflects that the info we've gathered here would have taken kilobucks & decamonths to circulate traditionally, with far fewer eventual recipients... 30th May 2004:As well as gunpowder & the compass, perhaps the ancient Chinese even stumbled on microwaves & these "scoops" may have been antenna all along? To prevent their secrets falling into barbarians hands,they were disguised as cookware! This could explain the Ming dynasty fascination with ceramics (= semiconductors ?). Such jests aside, parabolic reflectors uniquely have the property of a fixed focal point-unrelated to frequency. Hence our visible light technique in bringing the sun to a focus is valid for showing the WiFi sweet spot. Aha-this means any microwave wireless device at the FP could be enhanced! Bluetooth (also on 2.4GHz) is an obvious swap out, but quick checks indicate GSM cell phones (900/1800 MHz) & even Wellington's new Woosh IPWireless (~2GHz) indeed show better performance. Downlink signal levels came up ~2 bars on the latter, although Woosh signals failed to connect when ~10km LOS! Small cell radius (apparently 6.5km) maybe? Naturally a cradle to hold these devices would be needed, but it could allow indoor coverage in marginal regions without costly external antenna. See pictures above 7th June 2004: Trials with Aluminium foil glued to the fabric of assorted (~600mm diam) umbrellas gave mediocre WiFi results (as did metallic spray paints) even though the resulting dishes verified as bringing the sun to a good focus. No doubt the resulting poor electrical continuity to blame-silver paints of course have aluminium particles finely distributed. Such antenna are VERY wind prone & thus hazardous anyway - suggest insect screen mesh used instead if outdoor umbrella dishes developed, even if short term & well attended ! New DSE NZ XH6859 adaptor,also a ZyDAS ZD1201, tested as identical to their original XH6822. Darwin Dave's dinkum Aussie blog covers a similar (?) DSE Oz. XH4268 Spirit. 30th June 2004: WiFiFoFum (WFFF)just tamed for our Dell Axim X5 & Socket CF WiFi card. PDAs of course normally have inbuilt antenna & hence the only viable way to boost weak WiFi reception is to gather signals & concentrate at a dish FP where the PDA (or cell phone!) is placed. WFFF looks ideal for organising such PDA signal boosters- recommended ! 19th July 2004: Case studies ? Confirmation tests ? Check web sites, inspired by our insights, that outline 3-5km LOS WiFi links via Greg's wok, Paul's cover & Pete's scoop (all in Ch.Ch -NZ), & also Ecrivain's dish (900mm DIY) & Anthony's scoops (both eastern US). All verify mesh scoops are indeed impressive performers, in spite of the USB adaptor's ceramic antenna just "spraying RF all over the place". Updating our own pattern field tests, using a rotating Lazy Susan kitchen support, confirms reception improvement ~15dB when directed at the distant signal source,but outgoing transmission gain may be less due to dish reflector "under illumination" ? Scope exists to gather this signal (small parabola, sardine can ?) for a more efficient directive spray feed? Even a telescope style Cassegrain? Perhaps microwave lens experiments too? Stay tuned ... 7th Sept. 2004: Wall Street Journal -page A1!: WSJ mention/pix (& /. again) yielding VERY solid feedback & indicates Kiwi #8 wire mentality still rather unique. NZ is full of such lateral thinking in fact, epitomised by our productive farmers ! Silicon Chip , the popular Australian electronics monthly, features this DIY WiFi antenna in their Sept. 2004 issue. 28th Sept.2004: This really made our day - a relief organisation in Afghanistan rustling up WiFi links via our USB "scoop" ! 30th Sept.2004: USB adaptors, without extra antenna, can solve short range commercial LAN needs quickly & cheaply. 10th Oct. 2004: USB antenna ideas continue to roll in, including a Dragonfly Yagi & commercial lamp shades ! 14th Oct. 2004: US$10 ? Hamiltonian (NZ) Geoff.Thornburrow's superb USB + DIY mesh dish looks a winner. 17db ? 20th Oct. 2004: Fine wire mesh (re)covered umbrella reflectors look promising -inspired by a UK ham radio idea. 24th Oct. 2004: Further mesh covered umbrella frame trials, especially with inverted umbrella & windproof golf types - handle & struts thus at dish rear! In fact NASA used such inside-out umbrella antenna with late 60s Apollo moon missions 6th Jan. 2005: Check recent DIY scoop dish pix from a Malaysian hi rise , & swivel mounted on an Oregon RV camper 2nd Feb.2005: Neater BOUTIQUE versions (12~15dB gain) suiting visually demanding indoor desktop use? Raw cookware can look -ah- "somewhat industrial" of course (!), so for a more professional look & mount, attach a scoop or large mesh sieve/food cover to a modified flexible stalk budget desklamp & base. Kitchen sieves aren't usually very parabolic, but if spray painted black both they & scoops look appealingly "invisible" indoors, & clamp versions conveniently grip shelves,desks, poles, office partition tops & even (PARKED!) car roof rails. Although more costly, a small salvaged set top TV dish can look particularly classy too ! Such designs almost merit production as a road warrior laptop accessory, particularly suiting areas with otherwise marginal WiFi signals (college dorms/libraries/fringe urban areas etc). Mmm - cottage industry anyone ? 10th March 2005: Brief Popular Mechanics mention - the 10 miles range claim was INCORRECT however, as just 3 miles (5km) LOS is more typical ... 17th March 2005: Small combo USB adaptor/"soft" AP dongles look appealing for impromtu APs, perhaps cookware antenna extended & directed. Typical on sale are the ZYAIR G-220 (~US$80) & slower B-220 (~US$40) units, with the 16dBm (40mW) JAHT WN-4054U 54Mbps "g" only ~US$30 from Newegg etc -offering WEP/WPA security & bridging too. These cheap "no-AP" AP combo units use an attached (always on) PC to act as the software based AP, & promise multiuser laptop based WLANs in moments- suit on-the-road meetings, events etc. (Soft AP programs- HostAP etc -are popular under Linux of course) 15th April 2005: "g" adaptors now taking over from "b", & as well as being faster (54Mbps verus 11Mbps) they offer superior weak signal reception! A Genius GW-7200U "g" (~US$40) showed ~10dB better Netstumbler signal levels to an obscured AP 100m away when trialled beside our classic Zydas "b". Scoop "g" tests across Wellington harbour found many APs(~-80dBi) ~10km LOS away that'd never before been detected as well. HOWEVER- the limiting factor now looks ones weak outgoing signal (this Genius is 16dBm ~40mW), meaning powerful remote APs may be heard, but NOT connected to. Argh! Just because you can detect them (via NS etc) doesn't mean they can hear YOU! Obviously a transmitter booster now needed, or improved focusing for outgoing signal? A deeper reflector,or Cassegrain design , may also help better illuminate the dish 28th April 2005: Don't know if we've coined a new term, but "WOKFI" is increasingly being used for parabolic cookware antenna such as ours! A compact commercial "keybola" version has been released in the Slovak Republic (Central Europe) @ ~US$30,but verification of their claimed 19dB(?) system gain awaited, since their reflectors 140mm (~6") diameter seems too modest for such a boost! It certainly looks most professional however! 18th May 2005: Before throwing $$$ around setting up a longer range (~several km?) community/commercial WiFi link,it's suggested an initial signal audit be done with a cookware parabola & WiFi PDA (or USB laptop) running NetStumbler etc. 2.4GHz wireless signals are often "all over the place" & even a few handspans can make a BIG difference when mounting more professional antenna & installing costly cable runs. This approach is akin to the classic use of a small portable TV set to find reception sweet spots around a property when installing a terrestial TV antenna. Best signals may NOT be where you think- site survey FIRST!Theoretical maths link analysis - perhaps via Electro-Comm G.B.P.P.R. web calculations - may also assist, BUT might not give the true picture in built up areas.
12th June 2005: "Sleeper" Bluetooth (BT) has finally arrived & range extensions to ~1km also look feasible using USB BT adaptors & parabolic cookware ! 21st June 2005: Passive repeaters may offer slight signal boosts in difficult conditions - trees/buildings in way etc. Solar powered "repeater" AP probably better? 8th Sept 2005: Check a 5 sector multi USB dongle "Pentenna",developed by Massey post grad student Gladwin Mendez to help explore WiFi security issues. 24th Oct 2005: Nov-Dec Tele-Satellite ,the worlds largest sat.TV mag (25th year,18 edns,14 langs) feature us (+ the recent 125 mile DefCon WiFi shootout). 24th Dec 2005: Hawking Tech's new HWU8DD desktop USB + small dish ( ~ US$70), although in the style of our boutique design , offers only 8dB gain... 9th Jan. 2006: The easiest way to evaluate prospective cookware reflectors is to simply match the catenary curve made by a short length of light hanging chain against your dishes profile. Although NOT a perfect parabola (even Galileo was fooled!) this is good enough for most WiFi work, & later focal point checking can be found by measurement/calculation/experimentation or reflecting the sun's rays. NB- although shallow dishes are more common with Sat. TV, deeper parabolas may be more useful with USB WiFi, since they better capture & direct your weak outgoing signals. Most USB WLAN adaptor transmitters are only ~40 mW... 13th Jan. 2006: Quick trials with Picaxe driven 1mW XBee "ZigBee" modules (a new micropower 2.4GHz wireless technique) yielded LOS ranges ~2km with #13 scoops at both ends. Even cardboard & foil template parabolas and corner reflectors enhance signals usefully- both for the ZigBee & USB WiFi setups. These fleapower ZigBee modules maxed out at ~200m with their bare 1/4 wave antenna, & the 24+ dB cookware system gain hence boosts ranges ~2x2x2x2= 16 times- consistent with each 6dB doubling range. MaxStream's more powerful XBee Pro (100mW & with a superior receiver) should hence yield LOS ranges only influenced by the earth's curvature! 29th Jan. 2006: Maths free parabolas? Clamped rods & thick sheets etc assume a parabolic shape when flexed! A few minutes hence with a flexible sheet offcut (plastic or metal),string, glue & cooking foil can give you up to 9dB gain - use the old "finger at the hot spot" trick to find the focal point via reflected sunshine. "Bendy" rulers can even be used ! RECOMMENDED WHEN NO OTHER COOKWARE MATERIALS TO HAND ... Mid May 2006: On the road with boat, bike, car or RV (recreational vehicle)? Many camp grounds & marinas now offer "free" WiFi, but metal camper walls,masts and buildings can frustratingly weaken signals. Rather than annoyingly move your boat,tent or camper just to improve reception,check USB approaches suggested by a Canadian RV group , & DIYer . Maybe take along a broom handle or fishing rod too? It beats having to park in a puddle next to the toilets... Consider also weather/insect/bird proofing the USB adapter & connection with perhaps- gasp!- a wide mouthed baby's bottle! June-Aug. 2006 : (Feedback after a RTW trip). WiFi networks now abound globally (although suitable cookware may be elusive!), & travellers should consider on the road wireless email/web browsing via a PDA or compact laptop, such as the reliable, sensitive & cheap (~US$400) Acer 3624WXCi. Although WEP is admirably now common,open APs are plentiful- often deliberately organised as a business draw card -camp grounds,pubs,coffee shops & even cyber towns etc. Surging global growth by Spanish WiFi business FON may even tempt enterprising minds to set up their own "Foneros" to make some $$ as a "Bill". Instead of open WiFi being "borrowed" , perhaps deliberately advertise access as a patronage benefit - similar to music,warmth or "bottomless coffee" in a cafe? Security should be the client's concern, much in the way Wellington's CafeNet cautions users.
A recent WIFi PDA 1km wander down down a Singapore street revealed ~150 APs, while a Hong Kong central tram top audit returned ~350 APs over the same distance (many of them vertical from towering appartments).Even "Wired Wellington" (NZ) showed ~250 in a similar stretch. Suburbs in UK or NZ etc now show APs ~every 100 metres- many open... Sadly Boeing's innovative on board WiFi, offered by carriers such as Lufthansa, has proven too costly & is about to be scrapped. There was nothing like sipping a beer while reading your email 7 miles above Nepal - quite takes you mind off the in flight movies & US/UK airport security chaos.
Mid Aug. 2006 : NZ "Telecommunications Review " WokFi Down South article by tech. guru & wordsmith Peter Edge -as used on "The Water Horse" movie 20th Aug. 2006: Esteemed Engenius/Senao USB WiFi products finally to hand, with Kapiti Coast (Wellington-NZ) firm Bits4showing keen 362-EXT prices! There's been positive web feedback about Senao's "362" offerings, mostly relating to their sensitivity & enhanced power, but NZ supplies have been previously erratic. Initial tests indeed confirm superior performance, ideal for difficult links- if your budget can cope. However transmitter output looks just 100mW (rather than the oft quoted 200mW) & distant (many km) APs often still could not be connected back to. Of course placement at the FP of a dish appeals, with encouraging results (~ 12dB),consistent with our earlier cookware findings. Performances from either "362" was much the same, but the external (362-EXT) antenna version is recommended, as it offers greater antenna flexibility- perhaps for a DIY biquad , even though significant SMA connector & coax hassles may then develop. Quick 362-EXT trials of the simpler bi-loop antenna were most promising however. Further 5m USB extension lead runs were handled without any problems- suiting device mounting in elevated signal sweet spots etc. Both ran warm,although reliably, & these Engenius/Seano USB units merit keen attention for demanding & more professional WiFi setups. 2007 UPDATE- 500mW Alfa competitor alert !
For tight budgets &/or with signals nearby,just start with US$10-$20 USB cheapies & experiment with DIY "WokFi" antenna. As ADSL broadband web access will rarely reach blinding speeds, perhaps consider the original (2003-2005) 11Mbps "b" adapters, which are now often "$0 after rebate/ free to a good home" or $ on Ebay etc. These may be fine in many barebones setups, although some may be "deaf", or become unreliable when hot & suffer annoying dropouts etc.
19th Oct. 2006 : NZ's TV3 "Campbell Live" had a
5 min. video on the remote Tuhoe iwi WiFi based broadband uptake. (Visited Tuhoe Edn. Auth. Nov.28th) 23rd Oct. 2006 : Joint presentation, with Gladwin Mendez, of these "poor man" WiFi ideas at APECTEL34 workshops - Auckland,NZ Late Oct-early Nov 2006 : Participating, demonstrating USB WiFi approaches & assisting with diverse workshops at AirJaldi summit, Dharamsala-Nth India Early Feb. 2007 : "WokFi" showed it's stuff to ~150 attendees at the geeky KiwiFoo invite only weekend gathering -Warkworth,Auckland,NZ. Mid Feb.2007 : An aluminium drink can 'flower' can give a suprisingly good (~6db?) signal boost! 23rd Feb. 2007: Auckland Herald (NZ) article on the Oamaru TV station's $10 wok antenna- their idea shown here 2004 (as the 'Cape Wanbrow'). Mid April 2007: Another INSTRUCTABLES article, and interview by US mag. Computer Power User for their July issue. Late May 2007: The range boosting Alfa AWUS036H high powered (500mW!) & sensitive (-96dBm) USB adapter has become available. Initial info impressive, but feedback still scarce- suggest a Google while awaiting posted results. For demanding links these look a serious competitor to the previously top dog 200mW Engenius/Senao SUB-362(ext), especially given the Alfa's attractive ~US$65 list price. Aug. 2007: Jose Pino (Texas) easily managed 13dB gain with a Linksys USB adapter & lid. Late Sept 2007: Initial ALFA AWUS036H testing yielded impressive results, with NS signals superior by ~6db (=range doubling?) to the esteemed Engenius/Senao "362". This ALFA additionally comes with drivers supporting Vista,XP,Win 2000,Win ME,Win98,MAC OS,Linux & even Win CE -plus a handy "soft AP" feature! The supplied double header USB cable (presumably for ports that can't supply enough current) was not found needed on a range of laptops here,but YMMV. No sign of overheating (which tellingly may relate to throttled back power as manual confusingly mentions both 13 & 27 dBm tx output),with installation a no brainer-almost too easy! Netstumbler friendly,although display readings "jumped around" at times on one XP laptop.
Both the ALFA & Senao perform superbly beside cheap USB dongles,& often linked (even bare) to remote APs that the dongles couldn't even NS detect! More involved testing seems justified however, with transmitter power claims especially in need of verification. Both drew much the same ~320-350mA USB port working currents, & compared with a cheapie 40mW USB adapter (measured as drawing ~270mA),this seems rather low for their much promoted "high power" ratings... Oct. 10th 2007: Soft AP features of the PSP MayFlash "WIFI LINK",a USB WiFi dongle marketed for the popular Play Station Portable ,allow very pleasing WiFi web connecting for other non PSP devices -laptops,PDAs etc. Field testing, using just the inbuilt WiFi features of a basic XP laptop, showed easy LOS soft AP connections of ~500m were possible to such a scoop mounted "WiFi LINK" . With a decent USB WiFi adapter (& antenna) at the roving laptop,ranges of several km should be feasible. Although a normal AP better suits long term links,such a cheap & easily setup soft AP favours informal WiFi coverage -suiting events & impromptu WLANs
FURTHER APPLICATIONS,INSIGHTS & FEEDBACK welcome! Use of material & pix "copyleft", but credit to this site appreciated
Refs: Diverse antenna texts, guides & WLAN handbooks festoon library bookshelves & Google. Perhaps the best known at present are-