Rabu, 21 Januari 2009

Wlan antenna cabling

Here are some types for antenna cable and connectors. Deliverers here are Elfa Ab and Farnell Components .
Evere part must have impedance of 50 ohm. The impedance of coaxial cable depends of ratio D/d where D is inner dia of the shield tube and d is dia of inner wire. The ratio is about 2.4 in the 50 ohm air insulated coaxial. Other insulate materials decreases the ratio with so called velocity factor.

A = N panel socket in the Antenna, type Radiall R161 404 000W. Elfa item 46-105-23, Farnell 310-025

B = N plug suitable for about 10 mm dia cable like H1000, same connector as for cables RG9 and RG214.
Elfa item 46-075-11, Farnell 309-989 or 143-784

C = Cable Belden H1000, low loss and semirigid, diameter 10.3 mm. Elfa item 55-914-25

D = N cable socket for 10 mm cable. Elfa item 46-086-00, Farnell 310-013 or 143-786

E = Adapter cable 50 cm long with N plug and a connector suitable for the wlan card.. The Orinoco card there is their private connector which is not sold separately. Whole Orinoco adapter cable is sold in wlan deliverers. Most other wlan cards have standard connectors as SMA, SMB, SMC or MCX.

11 July 2001
Martti Palomaki
Ilmajoki, Finland

Main page: Wlan antenna

Architects Make Building Easier

As many other concerns began to be recognised and complexity of buildings began to increase in terms of aspects such as services, architecture started becoming more multi-disciplinary than ever. Architecture now required a team of professionals in its making, an architect being one among the many , sometimes the leader. This is the state of the profession today. However, individuality is still cherished and sought for in the design of buildings seen as cultural symbols - the museum or fine arts centre has become a showcase for new experiments in style: today one style, tomorrow maybe

However, the architecture and urbanism of the Classical civilisations such as the Greek and the Roman evolved from more civic ideas and new building types emerged. Architectural styles developed and texts on architecture began to be written. These became canons to be followed in important works, especially religious architecture. Some examples of canons are the works of Vitruvius, the Kaogongji of ancient China and Vaastu Shastra in ancient India. In Europe in the Classical and Medieval periods, buildings were not attributed to specific individual architects who remained anonymous. Guilds were formed by craftsmen to organise their trade. Over time the complexity of buildings and their types increased. General civil construction such as roads and bridges began to be built. Many new building types such as schools, hospitals, and recreational facilities emerged.
Islamic architecture has a long and complex history beginning in the seventh century CE . Examples can be found throughout the countries that are, or were, Islamic - from Morocco and Spain to Turkey , Iran and Pakistan. Other examples can be found in areas where Muslims are a minority. Islamic architecture includes mosques, madrasas, caravansarais, palaces, and mausolea of this large region.
With the Renaissance and its emphasis on the individual and humanity rather than religion, and with all its attendant progress and achievements, a new chapter began. Buildings were ascribed to specific architects - Michelangelo , Brunelleschi, Leonardo da Vinci - and the cult of the individual had begun. But there was no dividing line between artist, architect and enginee, or any of the related vocations. At this stage, it was still possible for an artist to design a bridge as the level of structural calculations involved was within the scope of the generalist.
With the consolidation of knowledge in scientific fields such as engineering and the rise of new materials and technology, the architect began to lose ground on the technical aspects of building. He therefore cornered for himself another playing field - that of aesthetics . There was the rise of the "gentleman architect" who usually dealt with wealthy clients and concentrated predominantly on visual qualities derived usually from historical prototypes. In the 19th century Ecole des Beaux Arts in France , the training was toward producing quick sketch schemes involving beautiful drawings without much emphasis on context.
Meanwhile, the Industrial Revolution laid open the door for mass consumption and aesthetics started becoming a criterion even for the middle class as ornamented products, once within the province of expensive craftsmanship, became cheaper under machine production.

Building a Strong Core With Pilates

A vital part of the fitness package these days is core strength and flexibility. But, what is core strength and how do we get it?

In the past five years, there has been a growing interested in learning techniques in resistance or weight training, aimed at stabilizing and strengthening the core. It turns out that a strong core is more important than we ever realized.

The muscles of the core are those of the pelvis, spine, shoulders, and abdominals. There is not a human movement that is done that does not involve the muscles of the core, which stabilize the spine and move the body throughout its various tasks. If these muscles are weak, each movement becomes more laborious, causing the posture to degrade and an increased restriction of the muscles.

The core muscles are the catalyst that transfers energy from large muscle groups to smaller ones in the body. Pilates trains the body by mimicking the twisting and turning that occur with everyday chores and movements. If you properly train your core muscles, you can reduce the risk of injury while increasing strength along these same muscles for when you need them during the day.

In addition to strengthening the core muscles, Pilates helps to develop the platform for the actions of the arm, shoulders, and leg muscles. Pilates is an effective way to stabilize the core by developing core strength.

The core muscle themselves are made up of the muscles of the trunk and pelvis, the deep abdominal muscles that protect the spine, the oblique abdominals that run alongside the abdomen, the erector muscle, located in the lower back, and the muscles of the hips and pelvis. Just because you have a "six-pack," it doesn't necessarily mean that you have a strong or stable core. Some of the most important muscles to good core development actually lie just beneath the six-pack. These muscles, with the erector muscles, help you to maintain your balance and have good posture throughout your active day.

The first and most important aim of core strengthening with Pilates is in its performance of exercises that mimic everyday movements, but that isolate specific muscle groups while balancing and strengthening the core. The Pilates exercise program emphasizes using diagonal, rotating movements that promote balance and strength. Equipment such as balance beams, wobble boards, foam rollers, and fit balls are used while sitting or standing, but balancing all the while. The very best core exercises in the program involve moving while balancing one one leg, or shifting from one leg to the other, while performing the exercises.

However, Pilates is not the only way of strengthening the core muscles of the trunk, back, or pelvis. Using a variety of core exercises will better target the area. Some of the best ones are, of course, Pilates, sit ups or crunches, fitness ball exercises, and resistance exercises which use the dead lift, squat, and lunges. Another great type of exercise to strengthen the core uses the medicine ball, throwing overhead to a partner, or using a side pass, and other various exercises. Any of the balancing exercises using a wobble board, balance beam, or foam roller are also good for developing the muscles of the core. If you have access to any of this equipment, you can add these exercises to your Pilates routine and condition your core faster.

Trainers and enthusiasts alike have made Pilates core training part of their weekly exercise routines. Many experts in the field have said that you should not go through an entire week without some sort of core training, whether Pilates or something else.

American Association of State Highway and Transportation Officials

AASHTO is a leading source of technical information on design, construction and maintenance of highways and other transportation facilities, including aviation, highways, public transit, rail, and water.

Most Popular Titles From AASHTO:

  • AASHTO GDHS-5 AASHTO GREEN BOOK - A Policy on Geometric Design of Highways and Streets, 5th Edition
  • AASHTO HB-17 Standard Specifications for Highway Bridges, 17th Edition
  • AASHTO GDPS-4-M Guide for Design of Pavement Structures and 1998 Supplement
  • AASHTO VLVLR-1 Guidelines for Geometric Design of Very Low-Volume Local Roads (ADT<400)>
  • AASHTO RSDG-3-M Roadside Design Guide, 3rd Edition, Includes 2006 Chapter 6 Update (Print Edition Includes RSAP CD-ROM)
  • AASHTO GL-6 Roadway Lighting Design Guide
  • AASHTO GBF-3 Guide for the Development of Bicycle Facilities
  • AASHTO MUTCD Manual on Uniform Traffic Control Devices (MUTCD), 2003 Edition
  • AASHTO LRFDUS-4-M AASHTO LRFD Bridge Design Specifications, Customary U.S. Units, 4th Edition (Includes 2008 Interim Revisions)
  • AASHTO LTS-4-I2 2003 Revisions to the Standard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals, 4th Edition

How To Build A Tin Can Waveguide WiFi Antenna

for 802.11(b or g) Wireless Networks
or other 2.4GHz Applications

click on image to enlarge

Got no dough for a commercial WiFi antenna? Looking for an inexpensive way to increase the range of your wireless network? A tin can waveguide antenna, or Cantenna, may be just the ticket. This design can be built for under $5 U.S. and reuses a food, juice, or other tin can.

I am not an electrical engineer, nor do I have access to any fancy test equipment. I've built some antennas that worked for me and thought I would share what I learned. I have no idea if this is safe for your radio or wireless network equipment. The risk to you and your equipment is yours.

Building your Cantenna is easy, just follow these steps.

  1. Collect the parts
  2. Drill or punch holes in your can to mount the probe
  3. Assemble the probe and mount in can

Collect the parts:

You'll need:

  • A N-Female chassis mount connector.
  • Four small nuts and bolts
  • A bit of thick wire
  • A can

These vendors can supply the parts (the wire and can you provide yourself).

The Connector
A N type Female Chassis-mount connector. One side is N-female for connecting the cable from your wireless equipment, and the other side has a small brass stub for soldering on wire. These can be found at electronics stores internet suppliers (see the list below under "Connect your antenna..." If you shop around, you should be able to find these for $3-$5.

Nuts & Bolts
You'll need them just long enough to go through the connector and the can. I've used #6x1/4" stainless. If your N-connector is a screw on type, then you won't need the nuts and bolts.

You'll need about 1.25" of 12 guage copper wire. This wire will stick into the brass stub in the N-connector.

A Can
This is the fun part. You're looking for a can between about 3" and 3 2/3" in diameter. The size doesn't have to be exact. I made a good antenna with a Nalley's "Big Chunk" Beef Stew can that was 3.87" in diameter. Others have reported good results with big 39oz. coffee cans that are 6" in diameter. The pringles can is really too small for good performance, however. Try to get as long a can as possible. The old fashioned fruit juice cans should work well.

Click on image to enlarge

Drill or punch holes in your can to mount the probe

The N-connector assembly will mount in the side of your can. You need to put holes in the right place to mount the connector. The placement of the hole and connect is very important. It's location is derived from formulas that use the frequency that the antenna will operate at and the can diameter. To make life easy on you, here's a calculator to figure it out for you.

Can Diameter

Cuttoff Frequency in MHz for TE11 mode


Cuttoff Frequency in Mhz for TM01 mode


Guide Wavelength in Inches


1/4 Guide Wavelength


3/4 Guide Wavelength


Enter the diameter of your can above and click on the calculate button. 802.11b and 802.11g WiFi networking equipment operates at a range of frequencies from 2.412 GHz to 2.462 GHz. Ideally, with your can size, the TE11 cut-off frequency should be lower than 2.412 and the TM01 cut-off should be higher than 2.462. It would be good, also, if your can is longer than the 3/4 Guide Wavelength. If your can is a little off in length or diameter, don't despair, experimentation is fun!

You want to mark the location on the can where you will put the hole for the connector. The 1/4 Guide Wavelength number tells you how far up from the bottom metal end of the can to put the center of the hole. Open only one end of your can, eat the contents, and give it a good washing. You'll probably want to remove the label too. Use a ruler to measure up from the closed end 1/4 Guide Wavelength and mark the can with a dot.

If you've got a drill, select a bit that matches the size of the center of your connector. You may want to start with a small bit and work the hole larger and larger. You could even start with a hammer and nail, then use drill bits. If you don't have a drill, start with a nail hole and use a file to get the hole to the required size. If you're using a bolt on connector, make four more holes for the bolts - you can use the connector as a drilling guide.

Click on image to enlarge

Assemble the probe and mount in can

Now you'll need that bit of wire. You'll need a soldering iron or a friend with one as well. Cut the wire so that when it is stuck in the connector as shown, the total length of both the brass tube and wire sticking out past the connector is 1.21". Get as close to this length as you can.

When you've got your wire correctly sized, solder it into the connector keeping it as straight and upright as you can. When it's cooled, bolt or screw the assembly into your can. Put the heads of the bolts inside the can and the nuts on the outside to minimize the obstructions in your antenna. Your Done!

Connect your antenna to your wireless card or access point

To use your cantenna, you'll need a special cable commonly called a "Pig Tail". The pig tail connects your wireless card or access point to you antenna. One end of the cable will have a "N" Male connector (just right for connecting your your cantenna), while the other end will have a connector appropriate to your card or access point. For a good picture of a pig tail, take a look at:

You'll want to have a wireless NIC or access point with an external antenna connector. Otherwise, you may have to hack into the one you have to hook up the cable. I wouldn't recommend this unless you're good with a soldering iron and electronics. For this reason, I like the Agere Orinoco cards which have a nice antenna connector. Pig Tails can be hand made if you have the right tools, but it's probably easier to get a pre-made one. Try:

Hook up your cable, point the antenna at a friend's, and see how far you can stretch you network. Be sure to let me know (greg@turnpoint.net) how it works.

This antenna has linear polarization. That means that how you rotate the antenna will affect the strength of your signal. Usually, you will want to put the connection straight down, but experiment with rotating the can while watching the signal strength on your PC to get the best performance.

For more information, check out these resources:

Go to the Homebrew WiFi Antenna Shootout

Go to the Wireless Home

Click on images to enlarge

Copyright 2003-2007 Gregory Rehm - All rights reserved.
For information about reproducing this article in any format,
contact the author: greg@turnpoint.net