Electric Rc Truck Motors
Electric Rc Truck Motors
5 Reasons Why Electric RC Helicopters Are So Appealing
RC Helicopters capture people’s interest since their very first inception. They stand as one of the most fascinating field of the RC hobby world. Very few can resist its charm. Nevertheless, not too long ago they also carried an extremely heavy price tag and required more maintenance than a ten-years-old car. To make matters worse, flying one required countless hours of practice and tremendous amount of patience. However, all that is about to change. With the introduction of electric RC helicopters, flying these amazing models are not as far-fetched as they used to be. Here are five reasons why:
1.Low Cost:
Flying RC Helicopter used to set people back thousands of dollars. People had to buy the helicopter kit (which comes in hundred small pieces – unassembled), servos, engine, starter, gyro, receiver, radio controller, a hundred other equipments, and of course – fuel. When everything has been purchased, you still have to assemble it!
On the other hand, electric helicopters almost always cost less than 200 dollars with cheaper but better versions coming out regularly. Even better, most of these helicopters come ready to fly right out of the box. In addition to that, every necessary equipments and accessories often come included as well. Finally, by using batteries, the running cost of these helicopters is greatly reduced as it is no longer necessary to buy gallons after gallons of gas.
2.Silent and Clean:
RC Helicopters might be amongst the most fascinating radio controlled models, however, one undeniable fact still stands against it; they make more noise and create more pollution than a breaking down truck. This makes flying around the neighborhood almost impossible.
The problem of noise, pollution and size is almost entirely eliminated with the electric models; the amount of noise greatly decreased while the amount of pollution vanished altogether. These two facts allows these machines to fly anywhere without causing too much annoyance to other people.
3.Reliable and Easy to Fly:
With gas helicopters, countless crashes occur not because of pilot errors, but because the engine fail in midair. Who’s to blame? After all, everybody knows that gas engines aren’t the most reliable thing in the world. They also notoriously require constant tinkering to run smoothly. On the other hand, electric helicopters fly undeniably more reliable. They almost never cut out in mid air, even when the battery runs down. Moreover, you can forget about having to crank up the engine over and over. These electric motors will run anytime anywhere as long as there’s battery. There’s nothing more frustrating than taking your helicopter to the field only to find that it won’t start because it is too cold, too humid, or just because the engine wants to act up.
Electric helicopter are generally easier to fly than gas models, making them ideal for beginners. Some model allows beginner to start out with only 2 or 3 channels to worry about as oppose to 6 or 7 that the gas model requires. Avid pilots won’t have to worry though, as professional fully 3D-capable electric models also exist.
4.Easy to Maintain:
Maintenance used to be one of the biggest hurdles for anyone wanting to start flying RC helicopters. Thankfully, electric RC helicopters tremendously decreased the amount of repairs required. These little wonders were specifically designed to keep the amount of fixing necessary to minimum. Therefore, repairs can usually be made with just the bare hands or with only one screw driver. Even more impressive is the fact that these types of helicopter rarely need repairing at all. They can survive most types of crashes without any problem.
5.Small Size:
Before electric helicopters, indoor flights and flights in your own backyard were next to impossible. Now, they are quick and easy. Newer versions are so small that even flying in the bedroom is possible. The smaller size of these helicopter means that it is easier to transport as well. However, for pilots who prefer big aircrafts, there are electric helicopters as big as.50 size gas models available.
The advantage of flying electric RC helicopter does not end with these five points. With new technologies becoming available, these aircrafts are improving at surprising speed. All in all, it is not hard to see why electric RC helicopter is the fastest growing field of RC hobby.
About the Author
Interested in the amazing hobby of Electric RC Helicopters?Tara Soonthornnont is an Electric RC Helicopter enthusiastwho maintains a website dedicated to it.Check Out
http://www.electric-rc-helicopter.com
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SnowEx SR210 3 Cubic Foot 12 Volt Wireless Remote Control Snow and Ice Melt Hitch Mount Broadcast Rock Salt Spreader $599.95 SnowEx WIRELESS UTILITY SPREADER Convenient, Wireless Operation for a Variety of Contractors and Uses! Whether youre a snow and ice rookie looking for an entry-level spreader or a seasoned veteran, these units are an economical solution for smaller applications. Mountable to a variety of vehicles including small pickups, cars and utility vehicles, the spreader features a wireless RF-remote that pr… |
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Neiko 880 Lb. Electric Hoist – With Remote Control $109.99 Perfect for your machine shop or monster garage to lift any heavy equipment or tools. Double Line Cable: 880lb. Single Line Cable: 440lb. Remote Control Cable: 5’5″. 110V, 60Hz, 1-1/8 hp motor delivers a line speed of 33ft per minute. Comes with a Heavy Duty Snap Hook, mount bracket included!… |
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Snap Circuits RC Rover $39.98 With the Elenco Electronics Snap Circuits RC Rover kit, your child can build a working, remote-controlled rover. Featuring specially designed snap-together electrical components, this innovative kit offers a fun, hands-on education in electronics, allowing kids to create rovers and other fun devices by snapping together working circuitry. Recommended for kids ages 8 and over, the RC Rover kit incl… |
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Traxxas 3340 Cooling Fan Velineon ESC $14.18 The Velineon® VXL-3s Accessory Cooling Fan reduces ESC temperatures during extended operation for maximum power flow. It securely clips onto the VXL-3s heatsink for easy installation. Wires are neatly routed thanks to the integrated connector clip. Simply plug the accessory cooling fan into the Velineon VXL-3s accessory power connector and clip the fan onto the heatsink for increased cooling…. |
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Maisto R/C Rock Crawler (Colors May Vary) $38.49 Take your radio control experience off-road with the all new Rock Crawler from Maisto. This off-road radio control truck boasts articulated suspensions, two motors and low gearing to make for awesome rugged off-road action. Rock Crawler is 12.5” long and sports both front and rear suspension. Tri-channel transmitter allows for three people to play simultaneously with their other Maisto radio cont… |
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Remote Control 4WD Tri-Band Off-road Rock Crawler RTR Monster Truck $41.99 From the Manufacturer Take your radio control experience off-road with the all new Rock Crawler from Maisto. This off-road radio control truck boasts articulated suspensions, two motors and low gearing to make for awesome rugged off-road action. Rock Crawler is 12.5” long and sports both front and rear suspension. Tri-channel transmitter allows for three people to play simultaneously with their o… |
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RM01 $16.40 Our universal remote kit allows you to switch any 12v product on and off with a press of a button. The kits include two (2) matching wireless remote control key fobs with LED indicator and batteries, one (1) ultra compact receiver unit with anti-code grabbing technology and full installation instructions. Works on any 12v electrical system, cars, trucks, motorcycles, boats, car alarms, car doors a… |
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LEGO City Cargo Train 7939 $179.99 Load up the new Cargo Train and send it down the line! Use the big crane to load and unload containers and cars from the train and container truck. Open the canopies on the engine to reveal the driver’s cabins on either end; use the 4-channel, 7-speed infrared remote control to transport the goods along the tracks around the LEGO® City! Includes 4 minifigures: 1 train driver and 3 freight yard wo… |
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The R/C Car Bible: How to build, tune and drive electric and nitro-powered radio control cars on and off-road $24.95 When it comes to scale-size motorsport thrills, few hobbies can match the untethered thrills of R/C cars. Whether screaming across the asphalt or bounding over a dirt course, R/C cars offer enthusiasts an ever-increasing level of power, detail, and sophistication. In this volume for veteran and newbie R/C enthusiasts alike, ace hobby writer Robert Schleicher offers a fully illustrated guide to bot… |
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Electric RC Car: Practical Truck & Truggy Upgrade Strategies $17.95 This book primarily covers EP offroad truck and truggy RTR R/C cars. Information presented is intended for beginners and intermediate users who want to upgrade their R/C cars cost effectively for the purposes of enjoyment and elementary-level racing…. |
Mattel Foundation
Mattel Foundation
Alexandra Rose Rieger Celebrity Supporter for Elizabeth Glaser Pediatric Aids Foundation*
On a sunny, cloudless afternoon in Brentwood, California, the Elizabeth Glaser Pediatric AIDS Foundation hosted the A Time for Heroes Celebrity Carnival, presented by Disney. The June 8 carnival was a huge success, providing a day of family fun and raising nearly $1 million to help support the Foundation’s lifesaving programs for children and families. The carnival has been a tradition in Los Angeles since Elizabeth Glaser and her two friends, Susie Zeegen and Susan DeLaurentis, started the Foundation nearly 20 years ago.
Ticket-holders knew they were in for a treat before they even arrived: A massive Ferris wheel emblazoned with the Foundation’s logo was visible for miles. But that was just the beginning. The carnival offered a dizzying array of activities – games, crafts, food, musical performances, and dozens of celebrity “heroes” who attended the carnival to help fight pediatric AIDS and have some fun of their own.
“The Elizabeth Glaser Foundation is just so special because they have improved the lives of millions of children who have been sent on this medical journey,” said actor Henry Winkler.
The Disney activities were clustered under a grove of shady trees, where actors Robin Williams and Blair Underwood dueled against young warriors with foam-rubber swords in Disney’s Voyage to Narnia, and actor Seth Green and Survivor host Jeff Probst read to children at Wonderland of Stories. Courteney Cox, David Arquette, and Marcia Cross hung out at Pixie Hollow, where children (and a few adults) designed their own fairy wings and wands, while teen actress, musician and youth ambassador Alexandra Rose Rieger was a celebrity reader in the fairytale inspired, Wonderland of Stories arena.
Guests with green thumbs had several activities to choose from: decorating bamboo pots at the “Grow Green, Grow Strong With Biolage” booth, staffed by several celebrity heroes, or making T-shirts and planting trees at Alternative’s Green Forest with actress Denise Richards and photographer Nigel Barker. Toddlers had a ball at the Sprouts Preschool Playzone, where they could pal around with Barney, design a card for a child in Africa, or practice yoga.
sports-minded kids raced Hot Wheels and putted golf balls at the Mattel Playground with Nicole Richie, musician Joel Madden, and Olympic figure skater Michelle Kwan, among others. The athletically inclined could also shoot hoops with L.A. Clippers star Cuttino Mobley or play in the learning area with Kelly Hu and Lance Bass.Throughout the day, DJ Nate and his team from Radio Disney entertained the crowd on the main stage. Carnival attendees also had the chance to meet several children and young adults living with HIV, who spoke on stage about their experiences. “I consider myself lucky to be alive,” said 17-year-old Alee Meredith, who was born with HIV. “One thing I’ve learned from my parents is that we can all get involved and make a difference. Elizabeth Glaser is proof of that. Everyone here is proof of that.”
Alexandra Rose Rieger, Nicole Richie and
Joel Madden at the the Elizabeth Glaser
Pediatric AIDS Foundation hosted the A
Time for Heroes Celebrity Carnival.
“Today’s infected children have so much more hope because of the efforts of the Elizabeth Glaser Pediatric AIDS Foundation,” said Marty, who was attending the carnival for the first time without her son. “I know that if we keep working together in the spirit of Brett and Elizabeth and so many others, we will see a day when every child has the chance to grow up as a healthy, happy adult.”
Jake Glaser, Elizabeth Glaser’s son, was the final speaker of the day. Jake encouraged each person in attendance to perform one act of kindness each day. “Everything you see today started with one person. One act of kindness,” Jake told the crowd. “Now I look out at you and see hundreds, which could turn into thousands…We can change the world.”
The 19th A Time for Heroes then entered the history books, leaving fans wondering what the 20th year will bring.
Alexandra Rose Rieger and Marcia Cross at the the Elizabeth Glaser Pediatric AIDS Foundation hosted the A Time for Heroes Celebrity Carnival.
*Source: the Elizabeth Glaser Pediatric AIDS Foundation website
About the Author
Style Entertainment is exclusive and operates internationally via “by referral only” providing Full Service:
-Film/TV Production & Investments
-Management
-Publishing
Contact: 310.288.2530
Write: info@style-ent.com
*Los Angeles * New York* Chicago* London * South Africa * Rio* Tokyo*
Which Foundation Should I Purchase?
I have Lightish Asian Skin and I have been looking for ages for a perfect foundation , I have come to the conclusion of either
Maybelline Dream Mattel Moose
Revlon Colourstay
and…
L’oreal Paris Inflallible
………………………………..Please could you also suggest an amazing concealer with the product you recommend (please also make sure that the one you suggest is avaliable in either boots or superdrug
thanks x
i use maybelline dream matte moose! its really good but only if your skin isnt too dry.
boots 17 cream concealer is really good if you use it with boots 17 foundations
they all come in many shades to suit all skin colours
superdrug me me me concealers are really good and they have green and purple ones too which neutralise red marks and dark under eye circles
Mattel Children’s Hospital UCLA Tour
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Barbie Collector Farrah Fawcett Doll $34.97 Farrah Fawcett is an American icon and world famous for her classic red bathing suit from the iconic 1976 poster. The body of the Barbie Collector Farrah Fawcett Doll is molded in the pose from the poster. She wears her iconic red bathing suit and comes with a blanket that is displayed in the poster. It’s a must-have favorite for any Barbie Collector — including the adult collector. Product Dimen… |
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Mattel Hot Wheels 1:18 1966 TV Series Batmobile $39.95 This is the one and only officially licensed model of the original 1966 Baobile featured in the TV series. Collectors have been waiting for this car, and our 40th anniversary seemed like the perfect time to release it. And since there are no others, we got together with George Barris to make sure we did it right. From the wheels to the curved windshield, 1966 TV Series Baobile is detailed on an as… |
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1966 TV Series Batmobile Batman Car 1/18 W1171 $42.95 Collectors have been waiting for this car for years, and Hot Wheels’ 40th anniversary seemed like the perfect time for them to release it! And since there are no others, they got together with George Barris to make sure they did it right. From the wheels to the curved windshield, 1966 TV Series Batmobile is detailed on an astonishing scale, embodying the history and heritage of Batman and Hot Whee… |
Exceed Sunfire Buggy
Exceed Sunfire Buggy
Exceed RC Sunfire Electric RC Buggy * Beginners Guide Part 1
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1/10 2.4Ghz Exceed RC Electric SunFire RTR Off Road Buggy (COLOR SENT AT RANDOM) $180.00 1/10 2.4Ghz Exceed RC Electric SunFire RTR Off Road Buggy – COLOR SENT AT RANDOM - Now with 2.4GHz, the most popular 1/10 4 wheel drive electric power off-road buggy in the world just got better! At each evolutionary step, the SunFire has been improved upon to keep it at the peak of the RC off-road buggy field. So how do you make an SunFire better? Extra speed, extra adjustability, extra toughness… |
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1/10 2.4Ghz Exceed RC Electric SunFire RTR Off Road Buggy Storm COLORS VARY SENT AT RANDOM $224.99 Length: 400 MM 15.7 inch. Width: 250 MM 9.8 inch. Height: 160 MM 6.3 inch. Wheelbase: 275 MM 10.8 inch. Ground Clearance: 26 MM 1.02 inch. Diameter Of Wheel: 86*32 MM (F) 86*40 MM (R) Battery: 7.2V 1800mAh Ni-Mh Motor: RC 540 Gear Ratio: 8.038:1 Contents: The new Exceed-Rc SunFire EP – 1/10 Scale Fully Ready to Run Electric Buggy includes just about everything you need in the box. Battery… |
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Exceed RC 1/10 Scale RTR Brushless Upgrade Version Sunfire Electric Buggy Storm Green (OR NEXT AVAILABLE COLOR SENT AT RANDOM) $359.99 The most popular 1/10 4 wheel drive electric power off-road buggy in the world just got better! At each evolutionary step, the SunFire has been improved upon to keep it at the peak of the RC off-road buggy field. So how do you make an SunFire better? Extra speed, extra adjustability, extra toughness! The new SunFire is packed with features that have been suggested by SunFire owners: More room for … |
Axial Symmetry Definition
Axial Symmetry Definition
Mattel Disney Castle
Mattel Disney Castle
Two Voices One Song, Barbie in the DIamond Castle
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Disney Tangled Rapunzel Deluxe Story Bag $21.00 Disney Tangled Rapunzel Deluxe Story Bag Inspired by Disneys new animated feature film Tangled. Now girls can play out all their favorite movie moments with the Rapunzel deluxe story bag shaped just like Rapunzels tower. Includes Rapunzel doll, Flynn Ryder doll, Maximus the horse, and chameleon Pascal. Plus fun new fashions and additional accessories for girls to take fairytale adventures anywhere… |
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Disney Tangled Featuring Rapunzel Magical Tower Playset $27.95 So delightful! Enchantawaits on every floor of this playset. Rapunzel’s hair “magically” glows no matter where she is in the tower. And fun hiding spots can be found if Flynn or Pascal need to hide!… |
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Disney Princess Ariel Bath Castle $15.99 Disney Princess Ariel Bath Castle Girls can play their favorite Little Mermaid moments in the bath. The castle playset includes an adventurous slide, flowers that spin with water power, a “magical” seashell that squirts water and more. Ariel mermaid doll and Flounder included. Doll cannot stand alone…. |
Axial Load Definition
Axial Load Definition
Leatt Adventure Neck Brace: Protection is Not Completed Without One
Leatt Adventure Neck Brace: Leatt’s Collection
If you have a caring for off-road racing, you should be by all odds searching into the assortment of neck braces and other motocross supplements from Leatt. They carry a deluxe collection that is fashioned to provide elated quality protection, which is needful in this sport. Otherwise, you will end up with lethal hurts and bad falls. Leatt’s neck braces like the Leatt Adventure neck brace curtails the rider from performing a array of far-flung moves but leaves plenty coverage for any sort of grave damage. All you necessitate is five minutes to realize used to wearing the neck brace, and after that, the rider senses vulnerable and exposed with them them off. The braces from Leatt work with all safety and seat belt configurations, and it will also sustain the safety harness in place specially during an impingement. It adapts and follows with all safety criteria and is SFI 38.1 certified. So when we say Protection is not Perfect without them, then are definite for telling you the truth.
Protecting the Neck Up
There is a Leatt Adventure neck brace specifically signified for the racers with a small and thin build, particularly in the age bracket 4 – 16 years old. There is also a different one for those with an average build with a maximum weight of 235 pounds, specially racers who are 16 years old and above. These neck braces bear been interjected with glass reinforced nylon that is projected by medical professionals specifically for motorcycle fanciers. It in general protects the head and the neck from hyperflexion, hyperextension, lateral hyperflexion, posterior hypertranslation, and axial loading. It holdscurbs head deceleration that may make sensitive injury to the brain. It also molds other in-car head motions after incurring multiple shocks such as during rollovers. These high-end elaborated neck braces have GP and X straps which ensure the rider in place and render a utmost degree of protective cover.
The Braces for the Masses
There are grounds why Leatt-Brace Moto GPX Club decided to bear a model neck security device for all mass motocross and off-road racers. There followed a require for a more low-cost neck protective gear, and so Leatt made a model device that will specifically supply to the market of off-road riders. Leatt Adventure neck brace was then introduced. It was made specifically for the mass market and for the touring and the commuting market. To match the monetary value, it has been contained and it is non-adjustable in the front but with a solid chassis construction on the rear. It applied akin figure and biomechanical function with other Moto GPX braces and will also impart easement from neck weariness.
You will ensure all motocross apparel, supercross gear, and other off-road sports apparel at Bob’s Cycle Supply. They consume all varieties of protective gears like the Leatt Adventure neck brace. Their online store offers over 26,000 items which is also offered in their catalog. They bear all of these items from identified producers. You do not have got to look anywhere else because you will for sure find out what you’ll want at Bob’s Cycle Supply.
About the Author
The
leatt adventure neck brace
is very fashionable & stylish available at http://www.bobscycle.com
Exceedance Probability
Exceedance Probability
High Probability Trading pt2
Daily Stock Report for Friday Morning, March 19, 2010 pt2
Summary Opinion
The Russell 2000 (small caps) and Nasdaq Composite (Techs) have exceed the January 2010 highs, establishing this as a bull market that is resuming after a pullback. When the Dow30 and S&P 500 exceed the January 2010 highs, stocks should move higher.
Calendar (All Eastern times)
Monday, 830am, Empire Mfg Survey, 21.45.
Monday 915am, Capacity Utilization, 72.6%
Monday, 915am, Industrial Production, 0.0%
Tuesday, 830am, Building Permits, 602K
Tuesday, 830am, Export Prices
Tuesday, 830am, Housing Starts, 570K
Tuesday, 830am, FOMC Rate Decision, 0.25%
Wednesday, 830am, Core PPI, 0.1%
Wednesday, 830am, PPI-0.2%
Wednesday, 1030am, Crude Oil Inventories, 0.2%
Thursday, 830am, CPI, 0.1%
Thursday, 830am Initial Claims, 450K
Thursday 830am Continuing Claims, 4500K
Friday, 1000am, Leading Indicators, 0.1%
Friday, Quadruple witching, S&P Index rebalancing.
Follow-up notes:
SWIR, Sierra Wireless has been on the Stock Table for the last couple of weeks and has been acting weak until the last three days in which it has moved up 13% from $8.00 to $9.05 and looks like it is going higher. If you are still long, consider holding until you get a sell signal on the 15 min, 5 day chart.
CNAM, China Armco Metals is still dropping and closed down 3.3% today (Thursday). REPEAT: Congrats if you are still short. Many times these bullshorts can have a swing to the downside that is exaggerated the same way it did going up. Consider covering anytime but watch it like a hawk now because these things have a nasty habit of going up sharply when they are near that target price to cover. Don’t give up much of your profits earned already.
Focus chart: (Worden Stockfinder chart)
AIG, American Int’l Group is starting to move up now and any put options are lowering in value after today’s small rise of 0.67%. It doesn’t take much movement in AIG (or any stock) to change the value of the options held long, in this case an April 40 put.
REPEAT:. Anyone with a April 40 call short, that were over $1.50 at one point when the stock was near $38 last week could easily hold those short unless you wanted to unlock all the buying power the brokerage firm is required to hold using strategy #2 below. This stock idea is essentially over now.
REPEAT: Remember that if you own the put options that you purchased on Thursday, you want to sell them as soon as possible because the time value (premium) will erode through time.
If you took the 2nd strategy outlined below, you want to have time go by while the stock stays below $40 and the time value erodes, which gives you lower prices you can buy to close those calls sold naked. Don’t open any more options or stock on this idea, it is too late. The train left the station last Thursday. The only transaction remaining on this idea may be intraday trading (scalping) OR a closing transaction of a short position of stock or for stock options.
REPEAT from Thursday: Today (Thursday) was likely the peak and although this may have a slight rebound tomorrow, today’s high was probably the high for this cycle and likely goes lower. Even though AIG stock did not reach the $40 price, either strategy listed in last night’s report was still working today. I personally like the #2 option below but requirements for having enough experience, option approval and larger account size make it impractical for most people.
REPEAT from Wednesday.: This is developing into a bullshort that people have been speculating that the government is going to restrict people from selling this stock short (and other stocks the government owns). But there is another way to profit from this without shorting the stock.
This is for experienced and aggressive investors with high risk tolerance. This involves stock options and make this position really small, please. Don’t get heavy or over-weighted with this strategy. This is high risk. This involves stock options and the two ways you can do this is outlined below:
Before you attempt this, wait for AIG stock to move higher, preferably over $40. It looks like it has more upside to it after being up 10.6% today (Wednesday). Somewhere around $40 would be where I’d consider opening a very small opening position but it could easily go higher.
1 You can buy put options LONG with, let’s say, a strike price of $40 and an expiration month of April. The root option symbol for AIG’s April 40 put would be IKG PH (verify this on your own). Currently the quote is bidding $6.80 and offering $7.00 and the AIG stock price is $36.00. As the AIG stock goes up, this option price would go down and you goal is to buy this put option at the lowest price when AIG’s stock peaks, whenever that is. It could be anywhere from $39-41. You don’t want to buy the March puts, you won’t have time for this to mature in your favor. If you do buy these, the ideal scenario is the stock drops quickly and you take profits quickly, perhaps in a few days. The longer you wait to sell, the faster the value of this option premium will drop (the 6.80 x $7.00 right now).
2 This strategy is extremely dangerous and requires a lot of money in your account. It also takes special approval in your brokerage account to do this, what most brokerage firms call option approval level 3. Please don’t use this technique unless you have already traded a lot of options and fully understand the risks. Theoretically this has unlimited potential for loss. And again, don’t build a big position in this, it could tie up your whole account in buying power and you could easily get margin calls or be forced to sell some contracts if you build too big of position in relation to the account value. This isn’t just a disclaimer, this is really advanced stuff and high risk. So you may ask, why am I even discussing this? Because it is really effective technique I use with bullshorts but you have to understand what you are doing first, OK? It’s usually very profitable but at least watch this on paper without you trading it, it’s a great tool to have in your bag.
So let’s say the stock moves up and peaks at $41 in the next few trading sessions. You sell the calls naked calls (same as selling the calls short) and the ideal scenario is you sell them when the stock is at its high. You would sell the April 40 calls, IKG DH at the highest price you can get. Currently they are bidding $2.05 and offering $2.14.
If AIG’s stock moves up to $41 for example, this option would probably be about $3.75 x $3.80. And if you sold 10 contracts, you would get 1,000 x $3.75 = $3,750 (1 contract controls 100 shares) and this would be credited into your brokerage account as soon as you sell them. If the stock drops as we expect AND stays below the $40 strike price at the expiration date (3rd Friday of April or April 16, 2010) you would get all the $3,750 and you would not even have to buy them back to close the option position. They would expire worthless and you get the whole premium. You can also trade them and buy them back before expiration like you would a stock. You can even work with the April 45 calls, IKG DI if the stock, AIG, goes up a lot more than we think, like near $45.
Well, there is a quick lesson on options. It is complicated, especially #2, and I expect you to fully understand this in the next 48 hours, lol!
Mitch King is the founder of TradeStocksAmerica.com. All material presented herein is believed to be reliable but we cannot attest to its accuracy. All material represents the opinions of Mitch King. Investment recommendations may change without notice and readers are urged to check with their investment counselors before making any investment decisions. Opinions expressed in these reports may change without prior notice. Mitch King and/or the staff at TradeStocksAmerica.com may or may not have investments in any stocks cited above before or after this newsletter is prepared. Use the stock table above as a model portfolio of ideas that look attractive at the time of the writing. Comments can be hypothetical in nature. Opinions expressed in these reports may change without prior notice. Disclaimer – Stock investing or stock trading has large potential rewards, but also large potential risk. There is risk of loss as well as the opportunity for gain when buying or selling stocks, bonds, option contracts or engaging in any strategy listed in the Daily Stock Report, The Wizard Training Course, The Trading Room and our seminar or workshops. You must be aware of the risks and be willing to accept the risks when investing or trading in any financial markets. Don’t trade with money you can’t afford to lose. This website is neither a solicitation nor an offer to Buy/Sell stocks. No representation is being made that any account will or is likely to achieve profits or losses similar to those discussed on this website. The past performance of any trading system or methodology is not necessarily indicative of future results.
About the Author
The Daily Stock Report Newsletter is a stock trading newsletter where you receive a text and video report the night before each trading day with stock picks, market commentary, trading strategies, and educational tutorials for online stock trading.
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Rainfall thresholds for forecasting landslides in the Seattle, Washington, area–exceedance and probability $14.13 Original publisher: Reston, Va.: U.S. Geological Survey, 2006. OCLC Number: (OCoLC)68961361 Subject: Landslide hazard analysis — Washington (State) — Seattle. Excerpt: … Table 5. Rain-gage agreement with regard to exceedance or nonexceedance of cumulative 3-day and previous 15-day threshold ( CT ). [ Gages A, B, and C are the three rain gages nearest to a landslide in the database, with th… |
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Ratios of uniform risk spectrum amplitudes for different probabilities of exceedance and for shallow, random seismicity surrounding the site (Report / … University of Southern California) … |
Axial Velocity Definition
Axial Velocity Definition
Coaxial cable
How it works
This section does not cite any references or sources.
Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (June 2009)
Coaxial cable cutaway
Like any electrical power cord, coaxial cable conducts AC electric current between locations. Like these other cables, it has two conductors, the central wire and the tubular shield. At any moment the current is traveling outward from the source in one of the conductors, and returning in the other. However, since it is alternating current, the current reverses direction many times a second. Coaxial cable differs from other cable because it is designed to carry radio frequency current. This has a frequency much higher than the 50 or 60 Hz used in mains (electric power) cables, reversing direction millions to billions of times per second. Like other types of radio transmission line, this requires special construction to prevent power losses:
If an ordinary wire is used to carry high frequency currents, the wire acts as an antenna, and the high frequency currents radiate off the wire as radio waves, causing power losses. To prevent this, in coaxial cable one of the conductors is formed into a tube and encloses the other conductor. This confines the radio waves from the central conductor to the space inside the tube. To prevent the outer conductor, or shield, from radiating, it is connected to electrical ground, keeping it at a constant potential.
The dimensions and spacing of the conductors are uniform. Any abrupt change in the spacing of the two conductors along the cable tends to reflect radio frequency power back toward the source, causing a condition called standing waves. This acts as a bottleneck, reducing the amount of power reaching the destination end of the cable. To hold the shield at a uniform distance from the central conductor, the space between the two is filled with a semirigid plastic dielectric. Manufacturers specify a minimum bend radius to prevent kinks that would cause reflections. The connectors used with coax are designed to hold the correct spacing through the body of the connector.
Each type of coaxial cable has a characteristic impedance depending on its dimensions and materials used, which is the ratio of the voltage to the current in the cable. In order to prevent reflections at the destination end of the cable from causing standing waves, any equipment the cable is attached to must present an impedance equal to the characteristic impedance (called ‘matching’). Thus the equipment “appears” electrically similar to a continuation of the cable, preventing reflections. Common values of characteristic impedance for coaxial cable are 50 and 75 ohms.
Description
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Coaxial cable design choices affect physical size, frequency performance, attenuation, power handling capabilities, flexibility, strength and cost. The inner conductor might be solid or stranded; stranded is more flexible. To get better high-frequency performance, the inner conductor may be silver plated. Sometimes copper-plated iron wire is used as an inner conductor.
The insulator surrounding the inner conductor may be solid plastic, a foam plastic, or may be air with spacers supporting the inner wire. The properties of dielectric control some electrical properties of the cable. A common choice is a solid polyethylene (PE) insulator, used in lower-loss cables. Solid Teflon (PTFE) is also used as an insulator. Some coaxial lines use air (or some other gas) and have spacers to keep the inner conductor from touching the shield.
Conventional coaxial cable has braided copper wire forming the shield. This allows the cable to be flexible, but it also means there are gaps in the shield layer, and the inner dimension of the shield varies slightly because the braid cannot be flat. Sometimes the braid is silver plated. For better shield performance, some cables have a double-layer shield. The shield might be just two braids, but it is more common now to have a thin foil shield covered by a wire braid. Some cables may invest in more than two shield layers, such as “quad-shield” which uses four alternating layers of foil and braid. Other shield designs sacrifice flexibility for better performance; some shields are a solid metal tube. Those cables cannot take sharp bends, as the shield will kink, causing losses in the cable.
Coaxial cables require an internal structure of an insulating (dielectric) material to maintain the spacing between the center conductor and shield. The dielectric losses increase in this order: Ideal dielectric (no loss), vacuum, air, Polytetrafluoroethylene (PTFE), polyethylene foam, and solid polyethylene. A low relative permittivity allows for higher frequency usage. An inhomogeneous dielectric needs to be compensated by a non-circular conductor to avoid current hot-spots.
Most cables have a solid dielectric; others have a foam dielectric which contains as much air as possible to reduce the losses. Foam coax will have about 15% less attenuation but can absorb moisturespecially at its many surfacesn humid environments, increasing the loss. Stars or spokes are even better but more expensive. Still more expensive were the air spaced coaxials used for some inter-city communications in the middle 20th Century. The center conductor was suspended by polyethylene discs every few centimeters. In a miniature coaxial cable such as an RG-62 type, the inner conductor is supported by a spiral strand of polyethylene, so that an air space exists between most of the conductor and the inside of the jacket. The lower dielectric constant of air allows for a greater inner diameter at the same impedance and a greater outer diameter at the same cutoff frequency, lowering ohmic losses. Inner conductors are sometimes silver plated to smooth the surface and reduce losses due to skin effect. A rough surface prolongs the path for the current and concentrates the current at peaks and thus increases ohmic losses.
The insulating jacket can be made from many materials. A common choice is PVC, but some applications may require fire-resistant materials. Outdoor applications may require the jacket to resist ultraviolet light and oxidation. For internal chassis connections the insulating jacket may be omitted.
The ends of coaxial cables are usually made with RF connectors.
Signal propagation
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Open wire transmission lines have the property that the electromagnetic wave propagating down the line extends into the space surrounding the parallel wires. These lines have low loss, but also have undesirable characteristics. They cannot be bent, twisted or otherwise shaped without changing their characteristic impedance, causing reflection of the signal back toward the source. They also cannot be run along or attached to anything conductive, as the extended fields will induce currents in the nearby conductors causing unwanted radiation and detuning of the line. Coaxial lines solve this problem by confining the electromagnetic wave to the area inside the cable, between the center conductor and the shield. The transmission of energy in the line occurs totally through the dielectric inside the cable between the conductors. Coaxial lines can therefore be bent and moderately twisted without negative effects, and they can be strapped to conductive supports without inducing unwanted currents in them. In radio-frequency applications up to a few gigahertz, the wave propagates primarily in the transverse electric magnetic (TEM) mode, which means that the electric and magnetic fields are both perpendicular to the direction of propagation. However, above a certain cutoff frequency, transverse electric (TE) and/or transverse magnetic (TM) modes can also propagate, as they do in a waveguide. It is usually undesirable to transmit signals above the cutoff frequency, since it may cause multiple modes with different phase velocities to propagate, interfering with each other. The outer diameter is roughly inversely proportional to the cutoff frequency. A propagating surface-wave mode that does not involve or require the outer shield but only a single central conductor also exists in coax but this mode is effectively suppressed in coax of conventional geometry and common impedance. Electric field lines for this TM mode have a longitudinal component and require line lengths of a half-wavelength or longer.
Connectors
A coaxial connector (male N-type).
Main article: RF connector
Coaxial connectors are designed to maintain a coaxial form across the connection and have the same well-defined impedance as the attached cable. Connectors are often plated with high-conductivity metals such as silver or gold. Due to the skin effect, the RF signal is only carried by the plating and does not penetrate to the connector body. Although silver oxidizes quickly, the silver oxide that is produced is still conductive. While this may pose a cosmetic issue, it does not degrade performance.
Important parameters
Coaxial cable is a particular kind of transmission line, so the circuit models developed for general transmission lines are appropriate. See Telegrapher’s equation.
Schematic representation of the elementary components of a transmission line.
Schematic representation of a coaxial transmission line, showing the characteristic impedance Z0.
Physical parameters
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Outside diameter of inner conductor, d.
Inside diameter of shield, D.
Dielectric constant of the insulator, . The dielectric constant is often quoted as the relative dielectric constant r referred to the dielectric constant of free space 0: = r0. When the insulator is a mixture of different dielectric materials (e.g., polyethylene foam is a mixture of polyethylene and air), then the term effective dielectric constant eff is often used.
Magnetic permeability of the insulator. Permeability is often quoted as the relative permeability r referred to the permeability of free space 0: = r0. The relative permeability will almost always be 1.
Fundamental electrical parameters
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Shunt Capacitance per unit length, in farads per metre.
Series Inductance per unit length, in Henrys per metre.
Series Resistance per unit length, in ohms per metre. The resistance per unit length is just the resistance of inner conductor and the shield at low frequencies. At higher frequencies, skin effect increases the effective resistance by confining the conduction to a thin layer of each conductor.
Shunt Conductance per unit length, in siemens per metre. The shunt conductance is usually very small because insulators with good dielectric properties are used (a very low loss tangent). At high frequencies, a dielectric can have a significant resistive loss.
Derived electrical parameters
Characteristic impedance in ohms (). Neglecting resistance per unit length for most coaxial cables, the characteristic impedance is determined from the capacitance per unit length (C) and the inductance per unit length (L). The simplified expression is (). Those parameters are determined from the ratio of the inner (d) and outer (D) diameters and the dielectric constant (). The characteristic impedance is given by
Assuming the dielectric properties of the material inside the cable do not vary appreciably over the operating range of the cable, this impedance is frequency independent above about five times the shield cutoff frequency. For typical coaxial cables, the shield cutoff frequency is 600 (RG-6A) to 2,000 Hz (RG-58C).
Attenuation (loss) per unit length, in decibels per meter. This is dependent on the loss in the dielectric material filling the cable, and resistive losses in the center conductor and outer shield. These losses are frequency dependent, the losses becoming higher as the frequency increases. Skin effect losses in the conductors can be reduced by increasing the diameter of the cable. A cable with twice the diameter will have half the skin effect resistance. Ignoring dielectric and other losses, the larger cable would halve the dB/meter loss. In designing a system, engineers consider not only the loss in the cable, but also the loss in the connectors.
Velocity of propagation, in meters per second. The velocity of propagation depends on the dielectric constant and permeability (which is usually 1).
Cutoff frequency is determined by the possibility of exciting other propagation modes in the coaxial cable. The average circumference of the insulator is (D + d) / 2. Make that length equal to 1 wavelength in the dielectric. The TE01 cutoff frequency is therefore
.
Peak Voltage
Outside diameter, which dictates which connectors must be used to terminate the cable.
Significance of impedance
The best coaxial cable impedances in high-power, high-voltage, and low-attenuation applications were experimentally determined in 1929 at Bell Laboratories to be 30, 60, and 77 respectively. For an air dielectric coaxial cable with a diameter of 10 mm the attenuation is lowest at 77 ohms when calculated for 10 GHz. The curve showing the power handling maxima at 30 ohms can be found here:
CATV systems were one of the first applications for very large quantities of coaxial cable. CATV is typically using such low levels of RF power that power handling and high voltage breakdown characteristics were totally unimportant when compared to attenuation. Moreover, many CATV headends used 300 ohm folded dipole antennas to receive off the air TV signals. 75 ohm coax made a nice 4:1 balun transformer for these antennas as well as presented a nice attenuation specification. But this is a bit of a red herring, when normal dielectrics are added to the equation the best loss impedance drops down to values between 64 and 52 ohms. Details and a graph showing this effect can be found here: [citation needed] 30 cable is more difficult to manufacture due to the much larger center conductor and the stiffness and weight it adds.
The arithmetic mean between 30 ohms and 77 ohms is 53.5, the geometric mean is 48 ohms. The selection of 50 ohms as a compromise between power handling capability and attenuation is generally cited as the reason for the number.
One reference to a paper presented by Bird Electronic Corp as to why 50 ohms was chosen can be found here:
50 Ohms works out well for other reasons such as it corresponds very closely to the drive impedance of a half wave dipole antenna in real environments, and provides an acceptable match to the drive impedance of quarter wave monopoles as well. 73 is an exact match for a centre fed dipole aerial/antenna in free space (approximated by very high dipoles without ground reflections).
RG-62 is a 93 ohm coaxial cable. It is purported that RG-62 cable was originally used in mainframe computer networks. (1970′s / early 1980s). It was the cable used to connect the terminals to the terminal cluster controllers. Later some manufacturers of LAN equipment such as ARCNET adopted RG-62 as a standard. It has the lowest capacitance per unit length when compared to other coaxial cables of similar size. Capacitance is the enemy of square wave data transmission and is much more important than power handling or attenuation specifications in these environments.
All of the components of a coaxial system should have the same impedance to reduce internal reflections at connections between components. Such reflections increase signal loss and can result in the reflected signal reaching a receiver with a slight delay from the original. In analog video or TV systems this visual effect is commonly referred to as ghosting. (see Impedance matching)
Issues
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Signal leakage
Signal leakage is the passage of electromagnetic fields through the shield of a cable and occurs in both directions. Ingress is the passage of an outside signal into the cable and can result in noise and disruption of the desired signal. Egress is the passage of signal intended to remain within the cable into the outside world and can result in a weaker signal at the end of the cable and radio frequency interference to nearby devices.
For example, in the United States, signal leakage from cable television systems is regulated by the FCC, since cable signals use the same frequencies as aeronautical and radionavigation bands. CATV operators may also choose to monitor their networks for leakage to prevent ingress. Outside signals entering the cable can cause unwanted noise and picture ghosting. Excessive noise can overwhelm the signal, making it useless.
An ideal shield would be a perfect conductor with no holes, gaps or bumps connected to a perfect ground. However, a smooth solid copper shield would be heavy, inflexible, and expensive. Practical cables must make compromises between shield efficacy, flexibility and cost, such as the corrugated surface of hardline, flexible braid, or foil shields. Since the shields are not perfect conductors, electric fields can exist inside the shield, thus allowing radiating electromagnetic fields to go through the shield.
Consider the skin effect. The magnitude of an alternating current in a conductor decays exponentially with distance beneath the surface, with the depth of penetration being proportional to the square root of the resistivity. This means that in a shield of finite thickness, some small amount of current will still be flowing on the opposite surface of the conductor. With a perfect conductor (i.e., zero resistivity), all of the current would flow at the surface, with no penetration into and through the conductor. Real cables have a shield made of an imperfect, although usually very good, conductor, so there will always be some leakage.
The gaps or holes, allow some of the electromagnetic field to penetrate to the other side. For example, braided shields have many small gaps. The gaps are smaller when using a foil (solid metal) shield, but there is still a seam running the length of the cable. Foil becomes increasingly rigid with increasing thickness, so a thin foil layer is often surrounded by a layer of braided metal, which offers greater flexibility for a given cross-section.
This type of leakage can also occur at locations of poor contact between connectors at either end of the cable.
Ground loops
A continuous current flow, even if small, along the imperfect shield of a coaxial cable can cause visible or audible interference. In CATV systems distributing analog signals the potential difference between the coaxial network and the electrical grounding system of a house can cause a visible “hum bar” in the picture. This appears as a wide horizontal distortion bar in the picture that scrolls slowly upward. Such differences in potential can be reduced by proper bonding to a common ground at the house. See ground loop.
Induction
External current sources like switched-mode power supplies create a voltage across the inductance of the outer conductor between sender and receiver. The effect is less when there are several parallel cables, as this reduces the inductance and therefore the voltage. Because the outer conductor carries the reference potential for the signal on the inner conductor, the receiving circuit measures the wrong voltage.
Transformer effect
The transformer effect is sometimes used to mitigate the effect of currents induced in the shield. The inner and outer conductors form the primary and secondary winding of the transformer, and the effect is enhanced in some high quality cables that have an outer layer of mu-metal. Because of this 1:1 transformer, the aforementioned voltage across the outer conductor is transformed onto the inner conductor so that the two voltages can be cancelled by the receiver. Many sender and receivers have means to reduce the leakage even further. They increase the transformer effect by passing the whole cable through a ferrite core sometimes several times.
Common mode current and radiation
Common mode current occurs when stray currents in the shield flow in the same direction as the current in the center conductor, causing the coax to radiate.
Most of the shield effect in coax results from opposing currents in the center conductor and shield creating opposite magnetic fields that cancel, and thus do not radiate. The same effect helps ladder line. However, ladder line is extremely sensitive to surrounding metal objects which can enter the fields before they completely cancel. Coax does not have this problem since the field is enclosed in the shield. However, it is still possible for a field to form between the shield and other connected objects, such as the antenna the coax feeds. The current formed by the field between the antenna and the coax shield would flow in the same direction as the current in the center conductor, and thus not be canceled, and would actually cause energy to radiate from the coax itself, making it appear to be part of the antenna, affecting the radiation pattern of the antenna and possibly introducing dangerous radio frequency energy into areas near people, with the risk of radiation burns if the coax is being used for sufficiently high power transmissions. A properly placed and sized balun can prevent common mode radiation in coax.
Miscellaneous
Some senders and receivers use only a limited range of frequencies and block all others by means of an isolating transformer. Such a transformer breaks the shield for high frequencies. Still others avoid the transformer effect altogether by using two capacitors. If the capacitor for the outer conductor is implemented as one thin gap in the shield, no leakage at high frequencies occurs. At high frequencies, beyond the limits of coaxial cables, it becomes more efficient to use other types of transmission line such as wave guides or optical fiber, which offer low leakage (and much lower losses) around 200 THz and good isolation for all other frequencies.
Standards
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Most coaxial cables have a characteristic impedance of either 50, 52, 75, or 93 . The RF industry uses standard type-names for coaxial cables. Thanks to television, RG-6 is the most commonly-used coaxial cable for home use, and the majority of connections outside Europe are by F connectors.
A series of standard types of coaxial cable were specified for military uses, in the form “RG-#” or “RG-#/U”. They date from WW II and were listed in MIL-HDBK-216 published in 1962. These designations are now obsolete. The RG designation stands for Radio Guide, the U designation stands for Universal. The current military standard is MIL-SPEC MIL-C-17. MIL-C-17 numbers, such as “M17/75-RG214,” are given for military cables and manufacturer’s catalog numbers for civilian applications. However, the RG-series designations were so common for generations that they are still used, although critical users should be aware that since the handbook is withdrawn there is no standard to guarantee the electrical and physical characteristics of a cable described as “RG-# type”. The RG designators are mostly used to identify compatible connectors that fit the inner conductor, dielectric, and jacket dimensions of the old RG-series cables.
Table of RG standards
type
impedance
[ohms]
core
dielectric
overall diameter
braid
velocity factor
comments
type
[in]
[mm]
in
mm
RG-6/U
75
1.0 mm
Solid PE
0.185
4.7
0.270
6.86
double
0.75
Low loss at high frequency for cable television, satellite television and cable modems
RG-6/UQ
75
Solid PE
0.298
7.57
quad
This is “quad shield RG-6″. It has four layers of shielding; regular RG-6 only has one or two
RG-8/U
50
2.17 mm
Solid PE
0.285
7.2
0.405
10.3
Amateur radio; Thicknet (10BASE5) is similar
RG-8/X
50
1.0 mm
Solid PE
0.185
4.7
0.270
6.86
double
0.75
A thinner version, with the electrical characteristics of RG-8U in a diameter similar to RG-6
RG-9/U
51
Solid PE
0.420
10.7
RG-11/U
75
1.63 mm
Solid PE
0.285
7.2
0.412
10.5
0.66
Used for long drops and underground conduit
RG-58/U
50
0.9 mm
Solid PE
0.116
2.9
0.195
5.0
single
0.66
Used for radiocommunication and amateur radio, thin Ethernet (10BASE2) and NIM electronics. Common.
RG-59/U
75
0.81 mm
Solid PE
0.146
3.7
0.242
6.1
single
0.66
Used to carry baseband video in closed-circuit television, previously used for cable television. Generally it has poor shielding but will carry an HQ HD signal or video over short distances.
RG-60/U
50
1.024 mm
Solid PE
0.425
10.8
single
Used for high-definition cable TV and high-speed cable Internet.
RG-62/U
92
Solid PE
0.242
6.1
single
0.84
Used for ARCNET and automotive radio antennas.
RG-62A
93
ASP
0.242
6.1
single
Used for NIM electronics
RG-174/U
50
0.48 mm
Solid PE
0.100
2.5
0.100
2.55
single
0.66
Common for wifi pigtails: more flexible but higher loss than RG58; used with LEMO 00 connectors in NIM electronics.
RG-178/U
50
70.1 mm
(Ag plated Cu clad Steel)
PTFE
0.033
0.84
0.071
1.8
single
0.69
RG-179/U
75
70.1 mm
(Ag plated Cu)
PTFE
0.063
1.6
0.098
2.5
single
0.67
VGA RGBHV
RG-213/U
50
70.0296 in Cu
Solid PE
0.285
7.2
0.405
10.3
single
0.66
For radiocommunication and amateur radio, EMC test antenna cables. Typically lower loss than RG58. Common.
RG-214/U
50
70.0296 in
PTFE
0.285
7.2
0.425
10.8
double
0.66
RG-218
50
0.195 in Cu
Solid PE
0.660 (0.680?)
16.76 (17.27?)
0.870
22
single
0.66
Large diameter, not very flexible, low loss (2.5dB/100′ @ 400 MHz), 11kV dielectric withstand.
RG-223/U
50
0.88 mm
PE Foam
0.0815
2.07
0.212
5.4
Double
0.66
Sample RG-223 Datasheet
RG-316/U
50
7×0.0067 in
PTFE
0.060
1.5
0.098
2.6
single
0.695
used with LEMO 00 connectors in NIM electronics;
PE is Polyethylene; PTFE is Polytetrafluoroethylene; ASP is Air Space Polyethylene
Commercial designations
type
impedance
[ohms]
core
dielectric
overall diameter
braid
velocity factor
comments
type
[in]
[mm]
in
mm
H155
50
0.79
lower loss at high frequency for radiocommunication and amateur radio
H500
50
0.82
low loss at high frequency for radiocommunication and amateur radio
LMR-195
50
low loss drop-in replacement for RG-58
LMR-200
HDF-200
CFD-200
50
1.12 mm Cu
PF CF
0.116
2.95
0.195
4.95
0.83
low loss communications, 0.554 dB/meter @ 2.4 GHz
LMR-400
HDF-400
CFD-400
50
2.74 mm
(Cu clad Al)
PF CF
0.285
7.24
0.405
10.29
0.85
low loss communications, 0.223 dB/meter @ 2.4 GHz
LMR-600
50
4.47 mm
(Cu clad Al)
PF
0.455
11.56
0.590
14.99
0.87
low loss communications, 0.144 dB/meter @ 2.4 GHz
LMR-900
50
6.65 mm
(BC tube)
PF
0.680
17.27
0.870
22.10
0.87
low loss communications, 0.098 dB/meter @ 2.4 GHz
LMR-1200
50
8.86 mm
(BC tube)
PF
0.920
23.37
1.200
30.48
0.88
low loss communications, 0.075 dB/meter @ 2.4 GHz
LMR-1700
50
13.39 mm
(BC tube)
PF
1.350
34.29
1.670
42.42
0.89
low loss communications, 0.056 dB/meter @ 2.4 GHz
There are also other designation schemes for coaxial cables such as The URM, CT and WF series
References for this section
RF transmission lines and fittings. Military Standardization Handbook MIL-HDBK-216, U.S. Department of Defense, 4 January 1962.
Withdrawal Notice for MIL-HDBK-216 2001
Cables, radio frequency, flexible and rigid. Details Specification MIL-DTL-17H, 19 August 2005 (superseding MIL-C-17G, 9 March 1990).
Radio-frequency cables, International Standard IEC 60096.
Coaxial communication cables, International Standard IEC 61196.
Coaxial cables, British Standard BS EN 50117
H. P. Westman et al., (ed), Reference Data for Radio Engineers, Fifth Edition, 1968, Howard W. Sams and Co., no ISBN, Library of Congress Card No. 43-14665
http://www.rfcafe.com/references/electrical/coax-chart.htm
Talley Communications CAxT Cable Assembly
Specs for MIL-C-17 Coaxial Cable Q.P.L.
Times Microwave Systems LMR Wireless Products Catalog
CFD Cable Specifications
Specs of RG174/U, RG58C/U etc.
RG213/8, RG218, CLX1/4″, CLX1/2″, CLX7/8″, CLX1+5/8″ Cable Power & Impedance Specs
Velocity factor of various coaxial cables
Pasternack 2009 Catalog
Union Copper site with pictures, diagrams, and spec sheet
Uses
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Short coaxial cables are commonly used to connect home video equipment, in ham radio setups, and in measurement electronics. They used to be common for implementing computer networks, in particular Ethernet, but twisted pair cables have replaced them in most applications except in the growing consumer cable modem market for broadband Internet access.
Long distance coaxial cable is used to connect radio networks and television networks, though this has largely been superseded by other more high-tech methods (fibre optics, T1/E1, satellite). It still carries cable television signals to the majority of television receivers, and this purpose consumes the majority of coaxial cable production.
Micro coaxial cables are used in a range of consumer devices, military equipment, and also in ultra-sound scanning equipment.
The most common impedances that are widely used are 50 or 52 ohms, and 75 ohms, although other impedances are available for specific applications. The 50 / 52 ohm cables are widely used for industrial and commercial two-way radio frequency applications (including radio, and telecommunications), although 75 ohms is commonly used for broadcast television and radio.
Types
Hard line
1-5/8″ hard line
Hard line is often confused with waveguide but the two are not the same. Hard line is used in broadcasting as well as many other forms of radio communication. It is a coaxial cable constructed using round copper, silver or gold tubing or a combination of such metals as a shield. Some lower quality hard line may use aluminum shielding, aluminum however is easily oxidized and unlike silver or gold oxide, aluminum oxide drastically loses effective conductivity. Therefore all connections must be air and water tight. The center conductor may consist of solid copper, or copper plated aluminum. Since skin effect is an issue with RF, copper plating provides sufficient surface for an effective conductor. Most varieties of hardline used for external chassis or when exposed to the elements have a PVC jacket; however, some internal applications may omit the insulation jacket. Hard line can be very thick, typically at least a half inch or 13 mm and up to several times that, and has low loss even at high power. These large scale hard lines are almost always used in the connection between a transmitter on the ground and the antenna or aerial on a tower. Hard line may also be known by trademarked names such as Heliax (Andrew), or Cablewave (RFS/Cablewave). Larger varieties of hardline may consist of a center conductor which is constructed from either rigid or corrugated copper tubing. The dielectric in hard line may consist of polyethylene foam, air or a pressurized gas such as nitrogen or desiccated air (dried air). In gas-charged lines, hard plastics such as nylon are used as spacers to separate the inner and outer conductors. The addition of these gases into the dielectric space reduces moisture contamination, provides a stable dielectric constant, as well as a reduced risk of internal arcing. Gas-filled hardlines are usually used on high powered RF transmitters such as television or radio broadcasting, military transmitters, as well as high powered amateur radio applications but may also be used on some critical lower powered applications such as those in the microwave bands. Although in the microwave region waveguide is more often used than hard line for transmitter to antenna, or antenna to receiver applications. The various shields used in hardline also differ; some forms use rigid tubing, or pipe, others may use a corrugated tubing which makes bending easier, as well as reduces kinking when the cable is bent to conform. Smaller varieties of hard line may be used internally in some high frequency applications, particularly in equipment within the microwave range, to reduce interference between stages of the device.
Radiating
Main article: Leaky feeder
Radiating or Leaky Cable is another form of coaxial cable which is constructed in a similar fashion to hard line, however it is constructed with tuned slots cut into the shield. These slots are tuned to the specific RF wavelength of operation or tuned to a specific radio frequency band. This type of cable is to provide a tuned bi-directional “desired” leakage effect between transmitter and receiver. It is often used in elevator shafts, underground, transportation tunnels and in other areas where an antenna is not feasible. One example of this type of cable is Radiax (Andrew).
RG/6
Main article: RG/6
RG/6 is available in three different types designed for various applications. “Plain” or “house” wire is designed for indoor or external house wiring. “Flooded” cable is infused with heavy waterproofing for use in underground conduit (ideally) or direct burial. “Messenger” may contain some waterproofing but is distinguished by the addition of a steel messenger wire along its length to carry the tension involved in an aerial drop from a utility pole.
Triaxial cable
Main article: Triaxial cable
Triaxial cable or triax is coaxial cable with a third layer of shielding, insulation and sheathing. The outer shield, which is earthed (grounded), protects the inner shield from electromagnetic interference from outside sources.
Twin-axial cable
Main article: Twinaxial cabling
Twin-axial cable or twinax is a balanced, twisted pair within a cylindrical shield. It allows a nearly perfect differential signal which is both shielded and balanced to pass through. Multi-conductor coaxial cable is also sometimes used.
Biaxial cable
Main article: Twin-lead
Biaxial cable, biax or Twin-Lead is a figure-8 configuration of two 50 coaxial cables, externally resembling that of lamp cord, or speaker wire. Biax is used in some proprietary computer networks. Others may be familiar with 75 biax which at one time was popular on many cable TV services.
Semi-rigid
Semi-rigid cable is a coaxial form using a solid copper outer sheath. This type of coax offers superior screening compared to cables with a braided outer conductor, especially at higher frequencies. The major disadvantage is that the cable, as its name implies, is not very flexible, and is not intended to be flexed after initial forming. (See “hard line”)
Conformable cable is a flexible reformable alternative to semi-rigid coaxial cable used where flexibility is required. Conformable cable can be stripped and formed by hand withouth the need for specialist tools, similar to standard coaxial cable.
Interference and troubleshooting
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Coaxial cable insulation may degrade, requiring replacement of the cable, especially if it has been exposed to the elements on a continuous basis. The shield is normally grounded, and if even a single thread of the braid or filament of foil touches the center conductor, the signal will be shorted causing significant or total signal loss. This most often occurs at improperly installed end connectors and splices. Also, the connector or splice must be properly attached to the shield, as this provides the path to ground for the interfering signal.
Despite being shielded, interference can occur on coaxial cable lines. Susceptibility to interference has little relationship to broad cable type designations (e.g. RG-59, RG-6) but is strongly related to the composition and configuration of the cable’s shielding. For cable television, with frequencies extending well into the UHF range, a foil shield is normally provided, and will provide total coverage as well as high effectiveness against high-frequency interference. Foil shielding is ordinarily accompanied by a tinned copper or aluminum braid shield, with anywhere from 60 to 95% coverage. The braid is important to shield effectiveness because (1) it is more effective than foil at absorbing low-frequency interference, (2) it provides higher conductivity to ground than foil, and (3) it makes attaching a connector easier and more reliable. “Quad-shield” cable, using two low-coverage aluminum braid shields and two layers of foil, is often used in situations involving troublesome interference, but is less effective than a single layer of foil and single high-coverage copper braid shield such as is found on broadcast-quality precision video cable.
In the United States and some other countries, cable television distribution systems use extensive networks of outdoor coaxial cable, often with in-line distribution amplifiers. Leakage of signals into and out of cable TV systems can cause interference to cable subscribers and to over-the-air radio services using the same frequencies as those of the cable system.
History
1866 First successful transatlantic cable, designed by William Thomson (Lord Kelvin, 1892); see Submarine communications cable.
1880 Coaxial cable patented in England by Oliver Heaviside, patent no. 1,407.
1884 Siemens & Halske patent coaxial cable in Germany (Patent No. 28,978, 27 March 1884).
1894 Oliver Lodge demonstrates waveguide transmission at the Royal Institution. Nikola Tesla receives U.S. Patent 0,514,167, Electrical Conductor, on February 6.
1929 First modern coaxial cable patented by Lloyd Espenschied and Herman Affel of AT&T’s Bell Telephone Laboratories, U.S. Patent 1,835,031.
1936 First transmission of TV pictures on coaxial cable, from the 1936 Summer Olympics in Berlin to Leipzig.
1936 World’s first underwater coaxial cable installed between Apollo Bay, near Melbourne, Australia, and Stanley, Tasmania. The 300 km cable can carry one broadcast channel and seven telephone channels.
1936 AT&T installs experimental coaxial telephone and television cable between New York and Philadelphia, with automatic booster stations every ten miles. Completed in December, it can transmit 240 telephone calls simultaneously.
1936 Coaxial cable laid by the General Post Office (now BT) between London and Birmingham, providing 40 telephone channels.
1941 First commercial use in USA by AT&T, between Minneapolis, Minnesota and Stevens Point, Wisconsin. L1 system with capacity of one TV channel or 480 telephone circuits.
1956 First transatlantic coaxial cable laid, TAT-1.
See also
Radio frequency power transmission
L-carrier
Balanced pair
Data cable
Shielded cable
Cable
Category 5 cable
References
^ Nahin, Paul J. (2002). Oliver Heaviside: The Life, Work, and Times of an Electrical Genius of the Victorian Age. ISBN 0801869099.
^ http://www.smarthome.com/7807R/Right-Angle-F-Connector-Adapters-6-Pack-2125/p.aspx
^ Elmore, William C.; Heald, Mark A. (1969). Physics of Waves. ISBN 0486649261.
^ Ott, Henry W. (1976). Noise Reduction Techniques in Electronic Systems. ISBN 0471657263.
^ RF Cafe – Coaxial Cable Specifications Cables Chart
^ “Radio City Inc”. http://www.radioinc.com/oscmax/catalog/product_info.php?name=LMR 400 UltraFlex (RG-8) 100 ft pre-cut&products_id=1121.
^ “Andrew Heliax”. http://www.commscope.com/andrew/eng/product/trans_line_sys/coaxial/wireless/1206774_13612.html.
^ “Cablewave Radio Frequency Systems (http://www.rfsworld.com)”. http://www.rfsworld.com/.
^ “Andrew Radiax”. http://www.commscope.com/andrew/eng/product/trans_line_sys/coaxial/radiating/1206639_13611.html.
^ IEEE – IEEE History Center: Landing of the Transatlantic Cable, 1866
^ Atlantic-cable.com – History of the Atlantic Cable & Undersea Communications from the first submarine cable of 1850 to the worldwide fiber optic network
^ HistoryMagazine.com – The Transatlantic Cable
^ PBS.org – The First Attempts to Lay the Transatlantic Cable (1857-1858)
^ Britannica.com – transatlantic cable
^ Google Book Search – Oliver Heaviside By Paul J. Nahin
^ Feldenkirchen, Wilfried (1994). Werner von Siemens – Inventor and International Entrepreneur. ISBN 0814206581.
^ “Coaxial Debut,” Time, Dec. 14, 1936.
^ Boing Boing – Gallery: An illustrated history of the transoceanic cable
^ Google books – Broadcast engineer’s reference book By Edwin Paul J. Tozer
^ Radio-electronics.com – Coaxial feeder or RF coax cable
^ Atlantic-cable.com – 1956 TAT-1 Silver Commemorative Dish
^ Google books – The worldwide history of telecommunications By Anton A. Huurdeman
Wikimedia Commons has media related to: Coaxial cables
v d e
RF connectors (coaxial)
APC-7 BNC C F FME Hirose U.FL IPX Motorola MCX MMCX N QLS QMA/QN RCA SMA SMB SMC Twin-lead TNC TV aerial plug UHF / Mini-UHF
Variations and alternate names: 2.9 mm (SMA) 7 mm Triax / Triaxial Twin BNC / Twinax (BNC) IPEX MHF AMC (UFL) SnapN RP-TNC RP-SMA
Old or seldom used: EIA GR LEMO 00 Musa
See also: Radio frequency Radio spectrum Audio and video connectors Audio and video interfaces and connectors
Categories: Signal cables | Antennas (radio)Hidden categories: Articles needing additional references from June 2009 | All articles needing additional references | All articles with unsourced statements | Articles with unsourced statements from June 2007 | Articles lacking in-text citations from June 2009 | All articles lacking in-text citations
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Mattel Disney Pixar Cars List
Mattel Disney Pixar Cars List
It’s the Year of the Pig for the Consumer
I opened my local newspaper on Saturday, September 22, 2007 and saw the picture of my wife’s bracelet on the front page. The bracelet, purchased for her birthday by a friend to benefit a local charity, was highlighted in color at the top of the page. The story indicated that the bracelet, made in China, was being recalled due to a high lead content. Her bracelet is just one example of a large number of consumer products that have been recalled from Chinese manufacturers in 2007.
The list of 2007 product recalls from China is not only large in number, but includes a wide variety of consumer products as well. The recall list includes the following items: Toxic lead paint is the problem in products that include jackets and overalls, bracelets, key chains, children’s rings, easels, paint, lunch boxes, necklaces, and wooden toys. However, recalled products extend beyond toxic lead paint to overheating ceramic heaters, flammable lamps and oil heaters, and remote controls. The extensive list of recalled products also includes breakable bike frames, faulty extension cords, poison pet food, hair dryers, faulty wall sconces and candles, flammable baby clothes, cribs, toxic fish, tires, seafood, toothpaste, glassware, hammocks, and even recliners.
The recalled products from China come from many major United States companies; such as, Mattel, Target, Family Dollar Stores, Holmes Group, Best Buy, Currey and Company, Kidsite Jewelry sold at Kmart, Toys R Us, Disney, Sears, Cracker Barrel Old Country Stores and many others.
The stories of tainted Chinese manufactured products are everywhere. Consider the following:
A California official discovered in July that 350,000 lunchboxes distributed as part of a promotion to encourage healthy eating in children contained significant amounts of lead. These lunchboxes were imported from China through a company called T-A Creations.
Earlier this year, more than 100 brands of cat and dog food were pulled from the shelves in the U.S. after pets died from eating food contaminated with the chemical melamine, traced back to wheat gluten from China.
In Panama, the deaths of some 51 people have been blamed on cough syrup tainted with Chinese-made diethylene glycol, commonly used in antifreeze. The same chemical has been found in toothpastes from China sold in the US and Canada.
Mattel has had three recalls of toys made in China in 2007. In total, Mattel has recalled nearly twenty million toys including Chinese-made Sarge die-cast toys from the Pixar film Cars which have lead paint. In fact an executive in charge at one Mattel supplier was reported as having killed himself last month after toys his firm made were among those recalled. Chinese media reported that Zhang Shuhong, co-owner of the Lee Der Toy Company, had been found hanged in one of his factories.
The US imports about one-fifth of its seafood from China. Some shipments were found to have traces of antibiotics and disinfectants that are banned in U.S. fish production. Other inspections uncovered fish products that were tainted with salmonella and pesticides. The U.S. Food and Drug Administration (FDA) recently imposed a nationwide hold on the import of five types of farmed fish and seafood from China.
China is taking the problem seriously. Recently, the former head of China’s State Food and Drug Administration, Zheng Xiaoyu was executed for corruption. However, China does not appear confident that their drug safety situation will be resolved anytime soon. Here is a recent quote from spokeswomen Yan Jiangying : “As a developing country, China’s food and drug supervision work began late and its foundations are weak. Therefore, the food and drug safety situation is not something we can be optimistic about.”
With Chinese imports totaling $288 billion per year, President George W. Bush has set up a panel to look at the safety of food and other products imported into the United States. He stated after the first meeting of the panel that, “the American people expect their government to work tirelessly to make sure consumer products are safe.” Others in Congress are calling for an “import czar” to oversee all products brought into the United States.
My wife is puzzled in deciding what to do with her colorful bracelet high in lead content. Since the charity is absorbing the cost of the recall, returning the bracelet would only hurt the good work of the charity and its foundation. The bracelet will probably remain in its box for now awaiting an uncertain future.
In China, this is the year of the Pig, which is an appropriate animal to highlight the quality of many of China’s manufactured products. In fact, the large number of Chinese product recalls are making 2007 the Year of the Pig for the consumer as well.
http://www.eworldvu.com
About the Author
James William Smith has worked in senior management positions for some of the largest financial services firms in the United States for the last twenty five years. He has also provided business consulting support for insurance organizations and start up businesses. Mr. Smith has a Bachelor of Science Degree from Boston College. He enjoys writing articles on political, national, and world events. Visit his website at http://www.eworldvu.com
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