AM / FM / SW Active Antenna: This circuit shows an active antenna that can be used for AM, FM, and shortw1ave SW. On the shortw1ave band this active antenna is comparable to a20 to30 foot wire antenna. This circuit uses receivers that use untuned wire antennas, such as inexpensive units and car radios. L1 can be selected for the application

An End Fed Antenna, L Match Coupler and Resistive Bridge for HF:

Antenna Extension Provides Open Door Policy: 02/16/98 EDN-Design Ideas

Antennas: Includes longwire, loading coil, active ferrite antenna, active short antenna, vertical.

ANTENNProjects:

ATL3 Loop Antenna:

Crossed Dipole GPS Antenna:

General Purpose RF Amplifier:

Long Loopstick AM Radio Antenna: Wound on a3-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. It works fairly well and greatly improved reception of a weak station130 miles away. A longer rod antenna will probably work better if space allows. The number of turns of wire needed for the Loopstick can be worked out from the single layer, air core inductance formula:

Pi Section Coupler:

Q Multiplying Loop Antenna:

QRP Antenna Tuner:

Small, 915 MHz antenna beats monopole: 05/15/03 EDN-Design Ideas / A 915-MHz data-acquisition project required a small antenna, but the available antennas lacked the necessary characteristics: efficiency, compactness—that is, smaller than a standard 3-in. monopole—with adequate bandwidth, and with amenability to modeling by inexpensive NEC-2 antenna softw1are...

T Volt / Radio Antenna Cable Galvanic Isolator:

Tesla Power Receiver:

Unamplified Four Foot Box Loop:

Yagi Uda Antenna :