pi calculator

W3FF Portable Dipole  ^pop - This is the antenna w3ff designed for his walking portable station. It is a dipole constructed out of the plastic plumbing pipe CPVC. There are telescoping whips at the ends of each side of the dipole, and these whips are adjusted to bring the antenna into resonance on each of five HF Bands 10, 12, 15, 17, and 20 Meters

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

SWR Calculator - BesserNet Reflectometer is a fun SWR calculator and simulator Java applet

Yagi Element Mounting Considerations - One of the most important considerations when designing and building a Yagi antenna is the method used to attach the elements to a boom. This is true because the boom influences the electrical length of the elements. In this article JH Reisert explain with drawings techniques on mounting yagi antenna elements to a boom

A $20 HF mobile antenna - A few hours of fun with PVC and wire and you’ve got yourself a respectable road radiator. The antenna consists of little more than some PVC pipe topped by a RadioShack replacement whip antenna and a couple of coils made from a small roll of #14 house wire.

Modified Buddipole for 40 to 10 Meters - This is modified version of buddipole antenna, using vertical wires instead of telescopic ends by ks7j

KS7J 5-band Cubex Quad - KS7J's Cubex 5-Band Quad, tests, pictures and modification of this five bands quad antenna

Long Loopstick Antenna - Wound on a 3 foot length of PVC pipe, the long loopstick antenna was an experiment to try to improve AM radio reception without using a long wire or ground.

Antenna Selection Made Easy - This page will help you answer important questions about antenna selection before you talk to a supplier. After reading this paper, you should be able to better determine the most important parameters you need to know for your antenna selection criteria.

Antenna Polarization notes - Antenna polarization is a very important consideration when choosing and installing an antenna. Most communications systems use either vertical, horizontal or circular polarization. Knowing the difference between polarizations and how to maximize their benefit is very important to the antenna user.

Antennas basics  ^pop - An antenna study guide by NZART, cover basic topics like dipoles, wave lenght calculation, baluns, beams, dummy loads, and measurements.

Remote antenna tuner controller - Software to remotely tune an HF antenna, included in help a principle hardware picture, by M.Recchia IK0VVE

Popular Wireless Magazines Priority listing - Since 1995, one of best places to go for information about GMRS and FRS. Offer a bulletin board community on the topic

Spider Antennas - Compact HF antennas for home and mobile use, compact HF maritime antennas, manufactured by multi-band antennas

Rigpix database -Yaesu - VX-7R - Picture and specifications for Yaesu VX-7R

Yaesu VX-7R Pictures - Yaesu vx-7r quad-band transceiver, includes several pictures of this yaesu transceiver

Yaesu VX-7R opinions - Forum tread about Yaesu VX-7R radio

Automatic Identification Systems (AIS) - Automatic identification systems (AISs) are designed to be capable of providing information about the ship to other ships and to coastal authorities automatically.

Alfa Lima International - A free radio station that is transmitting world wide on several shortwave frequency 's with loads of pirate and freeradio information.

HamCalc v1.3  ^pop - By G4VWL, HamCalc is collection of calculators for radio amateurs: Antenna ERP calculations. Attenuators. Audio Filter design.Coil Winding. Decibels. Great Circles map and calculator HF Filters HF Traps Metric conversions OP Amps QRA Locator to Latitude/Longitude (and back) Radio Horizon calculator Resonance Satellite orbit calculator Timer calculations (555 timer)Zener Diode calculations

SWR Calculator - Computes the Standing Wave Ratio, given the power readings on a line.

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

RF Coaxial Connectors - RF coax(ial) connectors are a vital link in the radio spectrum. Coax connectors are often used to interface two units such as the antenna to a transmission line, a receiver or a transmitter. The proper choice of a coax connector will facilitate this interface.

About Lightning Protection - What You Should Know About Lightning Protection by Joseph H. Reisert