background preloader

Homebrew antenna shootout

Homebrew antenna shootout
The Shootout My plan was to get relative performance measurements for various designs (including mine) of homebrew antennas for 802.11b (WiFi) wireless networks. To do this, I setup a wireless link and changed only the antenna- recording each antennas' performance under identical conditions. I didn't compare them to a commercial directional antenna as my only one has a male connector and I don't have the right cable to hook it up yet. The contestants were (click on each for design specifications). The Performance Summary The results surprised me! Of the waveguides, the Nalley's "Big Chunk" took top marks. With these results, I'm convinced that the waveguide design is the way to go for cheap wireless networking. The How To Build your own Tin Can Waveguide WiFi Antenna (Cantenna). Copyright 2003-2007 Gregory Rehm - All rights reserved. Related:  to build

Improved Dutch helix/helical for WLan Improved Helical Antenna Design for 802.11b WLAN By: PA0HOO October the 17th 2002 To slow? Dutch English N.B: (Click here to jump to the improved PVC helix design) Preface The weekend of October the 17th 2002 we tried to set up an 802.11b WLAN radio link over just 200m. The radio path 'Direct sight', seen from the roof. As we had to bridge about 200 m, an external antenna was a must. Making your own path calculation Click here to calculate the distance you can bridge with a given antenna. The connections for the external antennas These pictures show how the external antenna connections were made. Our experience: PTFE cables don't melt while soldering. 'The Antenna'At the site of Remco PA3FYM we found the perfect construction description of a classical helix antenna, using today's materials. The DisappointmentIt was very disappointing to find out that 'the thingy' we made wasn't performing at all. The dimension were OK, all sizes were according to the known formulas. The design The making The test

What can you do with an old pallet? So many things! If you ever come across the opportunity to pick up a few pallets take a look at some of the ideas I have come across for recycling old pallets into furniture and other practical and decorative pieces. I would like to mention that the designs below were found at various sources on the Internet. Make furniture for your home ABOVE: Mobius Living take pallets to a new level, offering clients the opportunity to buy ready-made coffee tables. ABOVE and BELOW: Who would have thought that a humble pallet could be transformed into so many practical pieces. ABOVE: All it takes is a few reclaimed timber pallets to make up your own living room furniture In the kitchen ABOVE and BELOW: Don't stop there... ABOVE: ReadyMade magazine transforms an ugly timber pallet into contemporary furniture for a dining room. In the bedroom ABOVE and BELOW: Complete your Shabby Chic bedroom with a rustic headboard made from... an old pallet ! In the garden Pallets for pets Find and prepare your pallet

Web site of: W1GHZ (n1bwt) NEW! Download the BD program for the Palm Pilot A work in progress: New Periscope antenna system for 10 GHz The flyswatter reflector, which rotates and tilts, is fed by a dish on the ground directly under it. Dick, K2RIW, has been talking about periscope antennas for so long that I had to put one up and show him how to do it! Now with new tilt indicator on flyswatter The tilt indicator is a Wineguard "Digital Magic" Elevation Sensing Unit. The periscope antenna worked great for rainscatter during the June 1998 VHF Contest. Here are some new sound clips of AF1T on CW and SSB. WA1MBA has written a good explanation of rainscatter. The following contacts were made with my dish pointed straight up through a skylight, into light snow in January, heavy rain in March: 10 GHz Snow scatter recordings from January VHF contest: Station #1 Station #2 Station #3 10 GHz Rain scatter recordings from 9 March 1997 Let me know how they sound! DSP guys - can you find a way to improve copy? N1BWT and KB1VC in action!

Antenna on the Cheap (er, Chip) Antenna on the Cheap (er, Chip) Rob Flickenger Jul. 05, 2001 05:20 PMPermalink Like many would-be 802.11b hackers, I'm increasingly obsessed with pushing more bits further and faster for less cost (I believe the unofficial goal of our community wireless project is to provide infinite bandwidth everywhere for free. Of course, there are problems with approaching infinity, but it's still fun to try!) The work that Andrew Clapp and others have done is helping to demystify the ancient black magick of Resonance (i.e. antenna building). And so, over last weekend, some friends and I decided to give it a go for ourselves. (standard disclaimer): Anything you do with your gear is YOUR RESPONSIBILITY. Anyway, our first run was a direct rip-off of Andrew Clapp's terrific original design (knowing next to nothing about antenna construction, it's helpful to start off with a working known good.) Once this was up and running, we looked at the design, and of course speculated about ways to optimize it.

15 Online Tools that You Will Come to Love as a Tech | EmergingT I have compiled a list of 15 free online tools that will help you greatly as a tech. I’m sure that there are other good ones that I have left out so please feel free to post the ones that you like as well. IPTools offers a wide variety of online networking tools. With this site you can look up IP address information, check spam databases, run pings, run traceroutes, lookup WHOIS information and much more. BugMeNot allows you to find and share logins for sites that require you to register. SpeedTest.net allows you to test your Internet connection speed. Del.icio.us is a social bookmarking site that allows you to bookmark sites and view them from any computer. Omnidrive is an online storage service that allows you to upload large files, access them from any computer, and share them with other people. 10 Minute Mail allows you to create temporary email addresses that expire after 10 minutes. Free Password GeneratorFree Password Generator generates very strong and unique passwords.

helical/helix antenna 2.4 GHz HOWTO MAKE I’ve built a lot of stuff with wood in my life, but I do not consider myself a “woodworker” by any stretch of the imagination. When I evaluate a project that uses wood, personally, what I look for is the maximum cool result for the least amount of technical skill and work. Here, then, are ten of my personal favorite bangiest-for-the-buck wooden projects from the vault. Beginner Woodworking Project for Illusionists? Nice DIY Bedframe Design DIY Wood toys for kids Weekend Project: Rok-Bak Chair Upcycling Wood Pallets How-To: Build Nob Yishigahara’s “Dualock” Cross Puzzle How-To: Trammel of Archimedes How-To: Build Large Couches on the Cheap Wooden Buttons From Fallen Branches Plywood Coffee Table Did I miss a good one? Related

Antenne En antenne i enkleste forstand er en elektronisk komponent som er laget for å sende og/eller motta radiosignaler. Mer spesifikt er en antenne en innretning av ledende materiale, hvis hensikt er å stråle ut (sende) et elektromagnetisk felt i respons med en pådyttet høyfrekvent elektrisk vekselstrøm, eller omdanne elektromagnetiske bølger til elektriske strømmer og spenninger som radiomottakeren mottar. En antennes utforming står i forhold til hvilken frekvens den skal brukes i. Formelen for bølgelengde er: 300/f (frekvens i MHz) = bølgelengde i meter. der λ er bølgelengden til en elektromagnetisk bølge.c er hastigheten til lys i vakuum, det vil si 299 792 458 m/s.f er frekvensen til bølgen. Ved 30 MHz er en bølgelengde 300/30 MHz = 10 meter I mobiltelefon er bølgelengden 300/915 MHz = 32 centimeter Måler du antennen på radioen, er den sannsynligvis 76 cm. 300/ 98MHz/ 4 = 76 cm En antennes evne/egenskap til å sende et signal måles i dB (desibel). Senderantenne[rediger | rediger kilde]

250+ working proxies for safe web access from work or school Ask the eConsultant : Technical Tips Proxy List : 250+ working proxies for safe access from work/school Just click on any proxy and enter URL on the resulting page. Report a new proxy / a non-working proxy : eConsultant » Blog Archive » Proxy List : 250+ working proxies for safe access Most Popular Pages : eConsultant | Blog | Articles | Book Reviews | Life Hacks | Lists | Personal MBA | Proverbs Archive | Quotations Archive | Selected Quotes | Technical Tips | Top Links | Web 2.0 { Contact | Resume } Gmail Tips - The Complete Collection Gmail Beta: First Impressions The other day, I received an "invitation" to beta test Google's new "Gmail" email service. After having tried and used literally dozens of web-based email services over the years, I decided to see what the buzz was all about, so I followed the Invitation instructions, and within a couple minutes, I had a new Google Gmail account. First off, please note that this article is based on the pre-release beta of Gmail, so presumably, the public release will have additions, changes, and improvements. Webmail While Web-based email is nothing new, Gmail introduces some new and unique concepts. But why use Webmail when I have a good client in Outlook? I'm going to first walk you through some of the "features" that make up Gmail. Advertising Let's start off with the "tough" issue first: Advertising. Gmail does not "read" your email. Google has been extremely open and forthcoming about its privacy policy and process. OK, I'll step down off of my soapbox now. Logging In 1.

Wi-Fi 2.4GHz helical antenna you can build! Wi-Fi point to point helical 2.4GHz antenna you can build! A while ago I thought I'd try my hand at building a 2.4GHz Helical. It was a sobering experience. The first design I tried to duplicate was Jason Heckers. I had read mixed reviews of his design. There was much conjecture regarding the dielectric constant of PVC and it's impact on tuning. The outside diameter was 38mm. Note in this chart that 14db return loss = a minimum target SWR of 1.5:1, 18db = an acceptable SWR of 1.29:1. The actual return loss measurements I got were less than satisfying and, despite claims by others to the contrary, my creation actually resonated higher than the design target, an interesting twist I didn't expect. Forging ahead I performed my gain tests. The best gain I was able to achieve with the helix pointed at the source was only 4 dB over the best half wave signal (4dBd) or 6dBi. Armed with this information my next prototype was based on the W0OQC design. Two things are for certain though.

Reviews: Insanely Easy DIY Projects Simplify Your Life We think these DIY projects are easy, useful and fun to do in good company.So, whether you engage yourself in this with a friend, roommate or significant other, you'll end up with something interesting to share through pictures later on!Lets begin, shall we? We think these would make a sweet gift for your roommate. Use bookends as floating book shelves. Practical and clean looking! Nail polish key covers. Create a couch from wooden pallets. Create a cool ambience for the occasional party or a cozy bedroom. Turn clothes hangers into shoe hangers. Use a window shutter for a mail holder. Make a lamp out of a water jug and a headlamp. Make a stool using old magazines, two belts and a pillow. Glue corks into a picture frame to make a bulletin board. Create letter bottles with a hot glue gun.

Privatradio Norge :: Vis Temaet - Ordliste Server's uptime and reliability Since august 2004, we have achieved 99.999% server's uptime. Hosted by liquidweb - one of the most reliable dedicated server provider - our servers are guaranteed 100% network uptime and 2 hours of hardware replacement. Our web network has been designed to accommodate clients demanding the highest quality network performance. There is a central focus on redundancy allowing our network to rapidly self-heal failures without interruptions to connectivity 1st November 2005 Hostingphpbb.com has hit 10,500 free forums. We might not be the biggest free forum provider, however we could be one of the most reliable free forum provider. Cheers ! Our server's specification Dual opteron 244 with 4GB DDR Registered ECC. We monitor our dedicated server frequently and upgrade them when necessary. Network uptime + speed is our main concern.

BLATANT PLUG FOR JUICE MONKEYS OF EDINBURGH OK, here’s the deal–if you’re looking for a good place to kick back with a smoothie, a coffee, a frappe, some fresh pastries or a sandwich, and surf the ‘net at the same time while visiting or living in Edinburgh, Scotland, you should pay a visit to Juice Monkeys. Check out their site at JuiceMonkeys.com. I’m loving the decore, the atmosphere, the people who work there, the drinks, and of course, the free Internet access. [ a vid I shot the other day of the interior of the place.] 54 Clerk Street Edinburgh EH8 9JB What this means if you’re not familiar with the lay of the land here is that if you’re in the center of Edinburgh (where all the good, old stuff is) go south on North Bridge. And no, I’m not getting a kick back for this post!! K, I’ve got some more blatant plugs later today.

Related: