low power

Constructing a LowFER Antenna - This article describes the antenna for Low Frequency Beacon. It originally appeared in the "Lowdown" for Oct. 1999.

Understanding Standing Wave Ratios SWR - We worry a lot about Standing Wave Ratio (SWR) in amateur radio since SWR is one indication of how well our antenna system is working. Most HF transceivers and antenna tuners have built in SWR meters. SWR is a measure of a transceiver’s output power verses the portion of that power reflected by the antenna system By Ken Larson KJ6RZ

Transmission Lines - Whenever you choose a coax feedline, the frequency of operation is a very important consideration. Over the operating bandwidth of the coax the VSWR is low, typically 1.2:1 or better. Insertion loss is also an important parameter. It is usually specified in dB/foot and is a linear relationship.

SWR: Maximum allowable VSWR - VSWR (voltage-standing-wave-ratio) represents the degree with which an antenna is "matched" to the system impedance. Most modern antennas do not require any tuning for optimum performance. VSWR is one of the easiest parameters to measure and VSWR meters are becoming very popular antenna installation tools

Setting the SWR of Your Antenna - SWR (standing wave ratio), is a measurement of how efficiently your antenna system will radiate the power available from your radio. In simple terms, your radio would like to radiate all of its power, but can only do so if the other components cooperate

Transmitter Power, Antenna Gain, Coax Loss - Understanding relatio among transmitter power, antenna gain, and coax loss Trade-offs by Ken Larson KJ6RZ

New HF antenna HB9ABX  ^{updated  pop} - A new, revolutionary design allows the construction of small HF antennas, which provide the same efficiency as large antennas. This antenna can be built for all HF bands, from 10 to 80 m.

Telewave - Telewave's innovative engineering produces the industry's toughest antenna systems. Yagi, Fiberglass Collinear, and Dipole models are available from 66-2500 MHz. Wattmeters, test equipment,rf power meters, duplexers, filters and cavities, transmitters combiners

About digital modes - The digital modes provide a wonderful opportunity for those of us who would like to work on the HF bands but find CW too difficult and SSB phone prohibitive because of interference problems. The digital modes are easy to set up and get operating, require low power and a narrow band.

CQ SSTV de KB4YZ - Amateur slow scan television and digital sstv by KB4YZ

HF Antennas for restricted space - Arrl document about invisible antennas and indoor systems. It is important to consider that few compromise antennas are capable of delivering the performance one can expect from the full-size variety. But the patient and skillful operator can often do as well as some fellows who are equipped with high power and full-size antennas. The "cliff-dweller" may not be able to "bore a hole" in the band as often, and as easily, but DX can be worked successfully when band conditions are suitable.

Isotron antenna manulas - From this page you can download the following manuals, in Adobe Acrobat format .pdf, 40 Meter Isotron, 80 Meter Isotron

Win APRS - Automatic Position Reporting System windows program, allow monitoring of real time geographical information such as the position of vehicles, the status of weather, radio direction finding and more.

Smith Chart Software - SimSmith is a highly interactive, real time Smith chart graphing program. Circuits are constructed using drag-n-drop. Load files can be imported from the EZNEC and CocoaNEC antenna simulation software and from the AIM4170 and miniVNApro antenna analyzers. Circuits and load files can be of any size. Key Features: SimSmith is one of the few Smith chart packages which models transmission line losses. SimSmith also allows the description of circuit elements using algebraic equations. SimSmith has only one screen and allows the screen to be resized to increase workspace or readability.

CW Decoder  ^pop - This program allows CW operators to copy CW code with a computer. The decoded CW is displayed as text or can generate a side tone. There is a spectrum display of the audio with a sliding cursor to select a particular audio for decoding. The program also allows for keying a transmitter from the keyboard with full CW break-in operation.

Morse Maker - MorseMaker is an up-to-date replacement for the Morse Machine shown further down this page. It has been re-written using a different programming language and is now entirely 'stand-alone' requiring no run-time support files. This version also works with Windows XP and can use the soundcard but please note that, unlike its predecessor, it does not split the alphabet into smaller 'learning' blocks and does not incorporate the Morse reader.

eQSLMaster - eQSLMaster is a HAM radio program, that allow to perform various functions using the Electronic QSL Card Centre (eQSL.cc). With eQSLMaster users of the eQSL.cc system have the ability to upload an entire ADIF format log file (or single QSO) and have it deposited into eQSL central database using LogServices.

RigResident - RigResident is a small program for RIG control, which does allow to set and read data of connected tranceiver (frequency, mode etc). RigResident supports more than 70 TRX models from ICOM, KENWOOD, YAESU and Ten-Tec.

Shortwave Log (SWLog) - Shortwave Log, SWLog is a comprehensive logging and radio control program. While designed for shortwave and mediumwave listening, the program is quite adept when listening to longwave, utility, or amateur radio. Support Icom Drake TenTec Yaesu JRC and lowe receivers.

DNBTV - This experimental software will send pictures or slow video directly from your webcam through your soundcard. you will need a webcam capable of 160*120 24bit RGB.

SpectraScope - SpectraScope is a simple Windows interface program allowing your computer to view up to two audio waveforms in either the time or frequency domain. The program is a Windows soft panel operating as a dual channel oscilloscope and spectrum analyzer. The useful frequency of operation is 20 to 10,000 Hz in the time domain and 20 to 20,000 Hz in the frequency domain. The program uses the computer sound card to capture the audio input.

Audio spectrum analyzer  ^pop - Analyzes audio from 10 Hz to 20 kHz, input from microphone or wave file, Variable sample rates (8000 Hz, 11025 Hz, 22050 Hz, 44100 Hz) Variable transform sizes (1k, 2k, 4k, 8k) Upper and lower limits adjustable Continuous, averaged, peak hold

Amateur Radio RF Safety Calculator - University of Texas Amateur Radio Club RF-Calculator. This is a main beam power density estimation program intended for use as part of a routine evaluation of RF safety compliance with FCC regulations

Safety: RF awarness guidelines - Although Amateur Radio is basically a safe activity, in recent years there has been considerable discussion and concern about the possible hazards of electromagnetic radiation (EMR), including both RF energy and power frequency (50-60 Hz) electromagnetic fields. This section summarizes what is now known and offers safety precautions based on the research to date.

Kenwood to pc serial ports - Simple, low cost interface between Kenwood serial ports and contest logging programs by Bob Wolbert, K6XX