RF Cafe Software

RF Cascade Workbook 2005 - RF Cafe
RF Cascade Workbook

Calculator Workbook
RF Workbench
Smith Chartâ„¢ for Visio
Smith Chartâ„¢ for Excel
RF & EE Symbols Word
RF Stencils for Visio

About RF Cafe

Kirt Blattenberger - RF Cafe WebmasterCopyright
1996 - 2016
Webmaster:
Kirt Blattenberger,
 BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:
 AirplanesAndRockets.com

Try Using SEARCH
to Find What You Need. 
There are 1,000s of Pages Indexed on RF Cafe !

Electronics World Cover,TOC,and list of posted Popular Electronics articles QST Radio & TV News Radio-Craft Radio-Electronics Short Wave Craft Wireless World About RF Cafe RF Cafe Homepage RF Cafe in Morse Code Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs Twitter LinkedIn Crosswords Engineering Humor Kirt's Cogitations Engineering Event Calendar RF Engineering Quizzes AN/MPN-14 Radar 5CCG Notable Quotes App Notes Calculators Education Magazines Software,T-Shirts,Coffee Mugs Articles - submitted by RF Cafe visitors Simulators Technical Writings RF Cafe Archives Test Notes RF Cascade Workbook RF Stencils for Visio Shapes for Word Thank you for visiting RF Cafe!

New Antenna to Multiply Field
January 1938 Radio-Craft

 

January 1938 Radio-Craft

January 1938 Radio Craft Cover - RF Cafe[Table of Contents]

People old and young enjoy waxing nostalgic about and learning some of the history of early electronics. Radio-Craft was published from 1929 through 1953. All copyrights are hereby acknowledged. See all articles from Radio-Craft.

Amateur radio enthusiasts are very familiar with burying ground radials below the surface (or sometimes just laid on top) in order to increase antenna efficiency by affecting impedance and, more importantly, the radiation pattern. Long distance (DX) operators generally prefer low launch angles over high angle 'cloud warmers.' Pittsburgh's KDKA, the country's first commercial broadcast radio station, built what would have been the mother of all ground radial arrays for its time - 360 (one every degree), 700-foot copper wires (8 AWG), for a total of a quarter million feet! It was laid using a farm tractor drawing a non-motorized trench cutter that looks like it came straight from the John Deere factory. It also implemented a new type of passive vertical suppressor element arrray.

New Antenna to Multiply Field

 718-foot antenna mast of KDKA - RF Cafe

The tall streak of light is the 718-foot antenna mast of KDKA in the glare of searchlights. It weighs 60 tons and rests on a socket in a large porcelain insulator.

 

 

Laying 50 miles of copper wire which is an unseen factor in the efficiency of the new KDKA antenna; it is buried about a foot deep, to form a ground. In the background, masts of KDKA's multiple system.

(Westinghouse photo) 

KDKA, which began systematic broadcasting on election night, 1920, last month completed the new antenna equipment, and the anniversary was celebrated (a couple of days early) on October 30. It is a double triumph for Dr. Frank Conrad, who sent out those first election returns; for the big antenna carries out an idea which he had in 1929, but which was unsuccessful at that time. The great self-supporting steel mast, 718 feet high, is a 3/4-wave antenna ; it is broken at the 336-foot level, and different voltages are fed to the upper and lower sections, so that current flows in the same direction in both, instead of reversing. Around the mast, 504 feet away, are 8 wooden masts each supporting - and this is a novel feature - a "suppressor" antenna. These buck the "skywave" from the main tower, and thus prevent fading and other undesired effects in the nearby service area. It is expected to increase efficiency tenfold, as regards "local" reception.

Another feature of the antenna system is a "ground" of 360 No. 8 copper wires, radiating from the foot of the mast to a distance of 700 feet. These, laid in shallow trenches dug by a tractor, are 48 miles in length overall and give a perfect counterpoise.

 

 

Control room at the transmitter of KDKA - RF Cafe

Looking from the control room at the transmitter of KDKA, now located at Saxonburg, Pennsylvania, the 17th anniversary of whose original faint broadcasts was last month celebrated. A tenfold increase in service area is to be obtained with the new antenna.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Posted  September 4, 2014