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 transceiverís output power verses the portion of that power reflected by the antenna system By Ken Larson KJ6RZ
- 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
New HF antenna HB9ABXpop
- 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'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 lowpower and a narrow band.
Antenna Noise and Signal Cancelling at LF
- The fact that the phasing between a wanted signal and an unwanted signal can be different on different antennas is put to advantage. With this condition, the unwanted signal can be cancelled out by controlling amplitude and phase. The heart of the system is some form of phase control circuitry.
- 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.
- 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.
- 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 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.
Assessing unknown Ferrite Toroids
- Ok so you have had a good day at the Rally and you have come back with a carrier bag full of ferrite toroids that "just might be useful for something". How do you find out what they are? Very few seem to be stamped with any indication of their properties, and some are 'painted' garish colours which presumably means something.
QRM and noise reductionPriority listing
- You will find on these pages my experiences and results on antennas and local/non-local QRM/noise reduction. Using a broadband vertical active magnetic loop and a home made / designed broadband amplifier. Two vertical magnetic Alford loops are used in an array.
Analog and Digital Signal Processing and a dual phase coherent Software Defined Radio (SDR) are used. By PA0SIM