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Showing posts with the label Hertz

Many antennas, multiple benefits. Post #364.

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Many antennas, multiple benefits : " Many antennas , multiple benefits", Jan 21, 2015 By combining large distributions of compact antenna nodes with fast fiber optic communication, researchers have developed a new wireless infrastructure ready for intense future demands. Credit: A* A*STAR Institute for Infocomm Research A concept that balances large-scale installations of low-cost and low-power antennas to boost cellular coverage in difficult environments will also provide better connectivity to more users. Developed by A*STAR, this new architecture for wireless communications can help service providers meet growing demands for increased network capacity and improved energy efficiency. Jingon Joung, Yeow Chia and Sumei Sun from the A*STAR Institute for Infocomm Research in Singapore sought to combine two state-of-the-art wireless technologies into a novel type of antenna system. The first technology, known as large-scale multiple-input multiple-output (L- MIMO ), use

Simple Ham Radio Antennas: A Portable 2 meter/70 cm Ham Radio Antenna. Post #303

KF7ETX has built an easily assembled portable VHF/UHF antenna system that can be set up most anywhere, from your home to an emergency station in the country. All it requires a painter's pole support mast , three paracord guy ropes , a dual-band 2 meter /70 meter antenna, and some low-loss coaxial cable. I have a similar arrangement at my QTH, where I use a homebrewed 5/8 wavelength 2 meter antenna supported by a 33-ft/10.06 MFJ telescoping fiberglass mast. The mast is secured by clamps on the side of my garage. I feed the antenna with 50-ft/15.24 meters of RG-213 coaxial cable. The mast can also be broken down for portable use. The antenna works very well from my rural location. The antenna used in this video by KF7ETX can be made from locally available materials from the nearest hardware or home improvement outlet. This is a simple, effective antenna that will give you hours of fun at your favorite park, beach, or mountain top. Have fun. Aloha es 73 de KH6JRM.

Simple Ham Radio Antennas. The Open-Wire Dipole (Doublet). Post #293

I'm still in the process of restoring my "antenna farm" after the passing of Tropical Storm Iselle on 07-08 August 2014.  I lost a few trees on my Orchidland Estates property, most of which were supporting several HF wire antennas.  I salvaged most of the wire and the 450 ohm feedline from the storm.  While I cleaned up the mess, I erected a simple multiband vertical antenna using a tall Norfolk Pine Tree as an antenna support. Next on the list is the restoration of my approximately 134-ft/40.85 meters  center-fed horizontal dipole.  The antenna is fed with 450 ohm ladder line which goes into a W9INN 4:1 balun and then via a short length of RG-8X coax into a MFJ 941E Versa Tuner II.  This feed arrangement allows multiband coverage from 3.500 MHz through 29.000 MHz. Although the antenna requires two tall supports (trees or masts), construction of the antenna is simple and the dipole doesn't require a ground radial system. Using the general formula, 468/f(

The Pine Tree HF Stealth Vertical Antenna. Post #289.

Now that Tropical Storm Iselle has left the state of Hawaii , those of us on Hawaii Island can complete the massive task of clearing roads, restoring power, and, in some cases, rebuilding our homes. Damage to my home was minimal with only fallen trees and "disassembled" wire antennas to be cleared from the property.  Our subdivision in the Orchidland Estates area of the Puna District escaped serious damage with only power interruption and blocked roads presenting major difficulties. When I surveyed the damage after the passing of the storm (07-08 August 2014), it soon became apparent that most of my "antenna farm" would have to be rebuilt.  The only antennas left intact were the 40/15 meter inverted vee and the NVIS 40 meter loop, which were lowered before the storm.  My 135-foot/41.15 meters doublet lodged in a 45-foot/13.71 meters tall eucalyptus tree was torn to shreds by windblown branches and fallen debris.  I did salvage the 450-ohm ladder line , a few

Simple Ham Radio Antennas. A 20 meter through 10 meter Vertical Dipole Antenna. Post #284.

One of the joys of moving into a bigger home with a decent back yard (1 acre of mixed brush and trees) is the ability to build the wire antennas I've always wanted.  Like many of my fellow amateur radio operators, I've endured HOAs, CC &Rs , and limited space for most of my 37 years as a ham.  I operated fairly well under these circumstances using stealth antennas from "ground hugging" loops to thin random wires stretching to the nearest tree. Now that my xyl and I are semi-retired, we have to the time to "fix up" our final home in an area conducive to our various hobbies, including gardening, amateur radio, backyard astronomy, and just plain relaxing.   Over the past few months, I've begun the erection of my "antenna farm" and the building of my radio room in the garage.  There's a lot of work to be done, but it's enjoyable and gives me exercise. Last Friday, just before the 2014 ARRL Field Day, I completed a new antenna whi

Simple Ham Radio Antennas. An 80-10 Meter Field Day Inverted Vee Antenna. Post #282

ARRL Field Day is right around the proverbial corner--28 June to 29 June 2014, to be exact.  According to the ARRL, more than 35,000 amateur radio operators used 2,500 emergency-powered stations to get on the air in 2013.   A similar number is expected this year. While many of our fellow amateurs will be heading to a Field Day site, there are a few of us, including yours truly, who will be operating under emergency conditions at home as 1E stations or as mobile stations as 1C.  For those of us home bound or forced by HOAs or CC & Rs to "hit the road" during Field Day, this national emergency communications exercise can be just as much fun and instructive as showing up a your club site. Before I retired from the commercial broadcast business, I usually worked Saturdays and Sundays in the news room, doing play by play over the radio, or hosting remote broadcasts from shopping malls and craft fairs.  Great work and lots of crazy people, but I often missed a chance to

Simple Ham Radio Antennas: The Aluminum Foil Vertical. Post #278.

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I knew it would happen.  The time I ran out of antenna wire.  After several years of using old #14 AWG house wire, #18 AWG speaker wire from Radio Shack , and remnants from studio wiring projects at my former employer (Pacific Radio Group), I had finally exhausted my wire supply for homebrewed antennas.  What to do until the next sale at Lowe's, Home Depot , and Ace Hardware?  Give up? Banish the thought!. With last week's beautiful weekend before me, I needed some cheap wire to erect my latest antenna "masterpiece."  I found my resource in the kitchen in the form of a new roll of "Diamond Aluminum Foil"--the stuff my xyl uses for cooking tasty treats and dinners.  Since there were several new rolls near the stove, I decided to "borrow" a new roll and apologize later.  Besides, I would buy another roll the next time I visited the supermarket. According to the label on the container, the roll contained 66.66 yards (199.98 feet) or 60.96 meters

Simple Ham Radio Antennas: An Extended Double Zepp for 20 meters. Post #277

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How would you like to have a simple dipole-like antenna that would give you almost 3dB over over the classical dipole antenna ?  You can if you're willing to build a Double Extended Zepp antenna for your favorite amateur radio band.   Now that I have enough room at my new home-in-progress in the Puna District of Hawaii Island, I decided to make a simple gain antenna for one of my favorite DX bands--20 meters. I had a spare MFJ telescoping fiberglass mast available, some leftover #14 AWG house wire in the garage, a spare 4:1 W9INN balun, a 50-ft./15.24 length of 450 ohm ladder line , a sturdy Drake MN-4 transmatch ("the tuner"), and 25-ft./7.62 meters of RG -8X coaxial cable with UHF connectors. I decided to configure the extended double zepp as an inverted V, knowing that its gain would be a bit less than a horizontal arrangement of a half wavelength dipole. With school over until mid-August, I thought this simple antenna project would give me something creat

Simple Ham Radio Antennas. A basic 40/15 meter dipole. Post #276

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My antenna "farm" at the new QTH finally is taking shape. So far, I've built and used successfully a 40-10 meter inverted V fed with ladder line , a 5/8 wavelength vertical for 20, 15, and 10 meters, a 135-ft/41.15 meters "classic doublet" fed with ladder line that works from 80-10 meters, and a 40-10 meter delta loop fed with ladder line.  I've described these antennas in past posts.  All of them work very well with relatively low power (less than 50 watts) with my older rigs (Argosy II, Swan 100 MX, Yaesu FT-7, and a Kenwood TS-520). Although I prefer multiband HF antennas fed with 450-ohm ladder line, I still use a few single or two-band antennas fed with 50-ohm coaxial cable when I wish to experiment on 40 or 15 meters.  Last Sunday, 18 May 2014, I decided to build a simple two-band dipole covering the 40 and 15 meter bands using a single piece of RG -8X coaxial cable. The dipole would be designed for the lowest frequency range and then use the thir

Simple Ham Radio Antennas: A 5/8 wavelength vertical ground plane. Post #272

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According to Edward M. Noll (W3FQJ), "The 5/8-wavelength vertical is a preferred length for the best low angle radiation."  For the higher HF bands (20 through 10 meters), this antenna is easily assembled and requires a small quantity of wire, some ceramic insulators, a suitable mast, 50-ohm feed line or 450-ohm feed line, a simple ground radial system, and a sturdy antenna matchbox or ATU .  Multiband use between 20 and 10 meters is possible with 450-ohm ladder line , ATU, and a balun, while good single band use can be obtained with 50-ohm coaxial cable and an inline or base antenna "tuner". So, let's build a simple 5/8 wavelength vertical for the 10 meter amateur radio band, centering on 28.4 MHz .  This frequency is at the mid-point of the SSB allocation for Technician Class licensees.  The antenna was built at my new home in the Puna District on 18 April 2014. MATERIALS: Using the general formula, 585/f (MHz)=L (ft), our vertical element will measur