Portable HF Transmitting Loop Antenna. November 12, 2004 While HF antennas are not normally known for their small size, magnetic loops can offer quite respectable performance, at the cost of some efficiency and extremely narrow bandwidth.
This tunable magnetic loop antenna is my contribution to the well established art of amateur loop making. It is small and light enough to carry while operating, it disassembles into small but rugged pieces that fit easily in a backpack or gym bag, and it can be tuned from 14 MHz to 30 MHz. Specs in Brief Frequency coverage: 14-30 MHz Efficiency: 32%@14, 54%@18, 66%@21, 78%@25, 87%@30 MHz Bandwidth: 12k@14, 20k@18, 30k@21, 50k@25, 100k@30 MHz SWR: 1.0:1 where tuned Power Handling: tested at 20W PEP Size: 21 inch square plus handle Weight: 4.5 pounds Theory of Operation For those unfamiliar with magnetic loop antennas, the principle behind them is simple.
For any given tuning, bandwidth is very limited, due to the high Q of the circuit. Construction Parts List Building the Main Loop Soldering Go. Ham Radio. Various stuff 1. Loop antenna: small loop. Amateur Radio II. Antennas. Transducer coils. DIY. DIY. Tech & Robots. Vector Network Analyser. Long range. Spl. Radio. Electronics. Loop antenna. Antennae design. ANTENNA. Conversions/Measurements/Calculators. Research & Reference. Network Tools. Unit 11 Further Mechanical Principles. Software for Electronics & Design. Calculators/Unit Converters. Programs and Calculators. MATH - Calculators. Code Practice QST Source. Code Practice Files. Text Source for W1AW Web Code Practice Files for April 15 and 16, 2014: Text for the 5 to 15 WPM runs comes from December 2012 QST, page 59.
Text for the 20 to 40 WPM runs comes from September 2013 QST, page 49. The various archive files are available from the following links. Access to each other archive is also available from any of these various pages: The 18 WPM is a "transition" file to help bridge the gap from 15 to 20 WPM. This particular file is actually part of the W1AW CW bulletin from previous weeks. The 40 WPM file is composed of texts taken from the lower speed files. The various TEXT files contain the actual code practice text used in each run. Please note the tone frequency is 750 Hz. Joe Carcia, NJ1Q - nj1q@arrl.org.
ARRL - The national association for AMATEUR RADIO. CQ - 'The Authority on Amateur Radio' for more than 65 years. United States Military Telegraph - Morse Code Files. The USMT CW Communicator Ionosphere server!
Use our server address of "cw.trwagner.org" in your CW Communicator program! Practice CW, DOT or any version of MorseCode you choose. For DOT Code, please use channel 1863. CW Comm is an excellent "live" or "real time" internet morse code program made by MRX Software. Using CW Comm, you can connect to a CW Comm server, called an "ionosphere". To help promote all versions of morse code, we've provided some links on the right-hand side of the page that may be useful. Below are some reviews of the programs above. CWirc, by Pierre-Philippe Coupard, is a plugin for the X-Chat IRC client to transmit raw morse code over the internet using IRC servers as reflectors. A brief note about CWirc; CWirc is quite flexible.
HAM OR, AMATEUR RADIO. Amateur Radio V. Quotes.