An antenna for 7MHz local contacts
- This article describes the design of an antenna for local contacts on 7MHz, including a simple and efficient matching system that presents a 50 ohm load to the transceiver.
RF Transmission Line Loss Calculatorupdated
- This calculator computes the matched line loss for a transmission line using a model calibrated from data for the transmission line types built in to the calculator.
It also gives an estimate of the mismatched loss if the mismatch is specified.
Some plain facts about multiband vertical antennas
- There is considerable confusion as to what exactly a multiband vertical antenna is. The confusion concerns the method of feed, how much mismatch one can expect, how many radials are required, how the particular antenna is built for multiband use, plus some other points.
Matching Waves, VSWR at work
- When the radiation resistance (voltage to current ratio) of an antenna is the same value as the characteristic impedance of the transmission line (voltage to current ratio in the line), all of the electrical energy transmitted down the line is taken by the antenna and radiated into space in the form of a radio wave.
10 m AerialMatching Unit
- This simple matching unit will allow a 10 meters aerial to be used right across the 10m band without the need to physically adjust the elements, and offers a virtual 1:1 VSWR at 50 ohms impedance to the transmitter.
The ElectraSlide Antenna
- Modification of the DK3 design by Don Johnson, W6AAQ. No voltage dropping, operates on the full 12 volts. The control switch and the matching toroid are supplied. All you need is a standard 3/8 by 24 thread ballmount, 2 wire sheilded microphone cable for control wiring, and a CB whip cut to resonance.
- Resistor Finder is a program that allows the electronics designer or hobbyist to find a combination of 2 resistors that, when connected in parallel, will provide the best match to a desired resistance.