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Active Antennas Schematics / Circuits / Notes

5 Watt FM Transmitter with Antenna 88-108 MHz - Two stages -- AUDIO AMPLIFIER AND OSCILLATOR and RF POWER AMPLIFIER

6x6 Antenna Loop

A magnetic loop antenna for 160 to 15m

A magnetic loop antenna for 40 to 17m local & DX contacts from tight spaces

A magnetic loop antenna for 80 & 40m an antenna for anywhere, even indoors!

QRP Homebrew

Active 3-30 MHz Hula-Loop Antenna for Shortwave - If you have a shortwave or high-frequency receiver or scanner that is struggling to capture signals with a short, whip antenna, and you'd like the kind of performance that a 60-foot 'longwire' antenna can provide but lack the space to put one up, consider...

Active Antenna for AM-FM-SW - This simple little circuit can be used for AM, FM, and Shortwave(SW). On the shortwave band this active antenna is comparable to a 20 to 30 foot wire antenna.  It is further more designed to be used on receivers that use untuned wire antennas, such as inexpensive units and car radios.

Active Antenna for HF-VHF-UHF

Active Antenna, easy to build - When fate or nasty neighbors prevent you from stringing a long-wire receiving antenna, you'll find that this pocket-size antenna will give the same, or even better, reception.  This "Active Antenna"
is cheap to build" and has a range of 1 to 30Mhz at between 14 and 20dB gain.

Active FM Antenna Amplifier - This amplifier will pull in al distant FM stations clearly.  The circuits is configured as a common-emitter tuned RF preamplifier wired around VHF/UHF transistor Q1

AM Band Antennas - Scroll down to find this circuit design.  A good AM Band antenna can be a simple long-wire strung between two trees or across the top of the roof. Even a modest length wire will give your receiver greatly improved reception with less static.

AM Loop Antennas (Bruce Carter)

AM/FM/SW Active Antenna - This circuit shows an active antenna that can be used for AM, FM, and shortwave SW. On  shortwave 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.

An end-fed antenna - L-match coupler and resistive bridge for HF one wire, all bands

AN710: Antenna Circuit Design - Microchip Application Note

AN831: Matching Small Loop Antennas to RFPIC Tm Devices - Microchip Application Note

AN868: Designing Loop Antennas for the RFPIC12f675 - Microchip Application Note

Antenna - This Antenna is most widely used all over  world. For example, when you see a police car it has a transmitter with Ground Pole Antenna The body of car serves as ground). It accepts load from 50 ohm source and has larger power output than Half-Wave Dipole Antenna.

Antenna Circuit Design - Microchip Application Note

Antenna Extension Provides Open Door Policy - EDN-Design Ideas:

Antenna Projects

Antennas - Ground Pole and Half-Wave Dipole Antennas

Antennas for HAM Transmitters - Describes how to construct various type of antenna for Ham Radio Transmitters.

ATL3 Loop Antenna - All ATL-3 loop windings are centre tapped and balanced w.r.t. their amplifier/receiver chassis ground, and therefore electric field interference pick up tends to self cancel. Magnetic noise fields, e.g. televisions and the electric meter box

Build a Yagi-Uda Antenna

Designing Loop Antennas for the RFPIC12f675 - Microchip Application Note

External Antenna for the GPS-38 Magellan 2000 or Eagle Explorer GPS Receivers

General Purpose RF Amplifier

Long Loopstick AM Radio 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. It works fairly well and greatly improved reception of a weak station 130 miles away. A longer rod antenna will probably work better if space allows.

Magnetic loop antenna for 160 to 15m

Magnetic loop antenna for 40 to 17m local & DX contacts from tight spaces

Matching Small Loop Antennas to RFPICTm Devices - Microchip Application Note

Medium Wave Active Antenna - This circuit is designed to amplify the input from a telescopic whip antenna. The preamplifier is designed to cover the medium waveband from about 550Khz to 1650Khz. The tuning voltage is supplieb via RV2, a 10k potentiometer connected to the 12 Volt power supply.

OA-26: OA-26 Designing Active High Speed Filters - National Semiconductor Application Note

Pedestrian mobile HF antenna

Pi Section Coupler

Q Multiplying Loop Antenna

QRP Antenna Tuner

QRP Links

RF Amplifier for Ferrite Bar Antennas

Shorty Forty Antenna - Do you have space limitation to put a 40 meter dipole. Try this Compact 40 meter antenna.

Small 915 MHz Antenna Beats Monopole - EDN-Design Ideas:

Tesla Power Receiver

The ATL-3 Loop Antenna - All ATL-3 loop windings are centre tapped and balanced w.r.t. their amplifier/receiver chassis ground, and therefore electric field interference pick up tends to self cancel. Magnetic noise fields, e.g. televisions and the electric meter box

The versatile end-fed wire - A piece of wire of almost any length can be used as an antenna on the HF bands. However, just because an antenna can be made to work is no guarantee that it will perform efficiently. This article will initially concentrate on the half wavelength of wire and its use.

Isolation between antenna network and TV/radio equipment

Unamplified Four Foot Box Loop

WIFI CAN Antenna - Got no dough for a commercial WiFi antenna? Looking for an inexpensive way to increase the range of your wireless network? A tin can waveguide antenna, or Cantina, may be just the ticket. This design can be built for under $5 U.S. and reuses a food, juice, or other tin can.

Wireless Phono Oscillator - A "phono oscillator" is a simple, short-range AM band transmitter that was typically used to send the signal from a phonograph to a nearby radio, eliminating the need for an amplifier and speaker. This version uses only one transistor....

YAGI UDA Antenna

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