security alarm circuit

Shorty Forty Antenna - Short dipole antenna for 40 meter ham band. Can be put up in the space required for a 20 meter dipole.

The EH Antenna analyzed - This report is a recent analysis of the EH antenna using the Pspice program and considering the antenna as a set of circuit elements

Single Coil Z Match - Single Coil Z Match, circuit Diagram and homebrewing notes

Remote Control Antenna Switch - The Remote Control Antenna Switch consists of two circuit boards. The control unit and the remotely controlled switch

Common Mode Choke Theory - A common mode choke may be used to reduce a type of electrical noise known as common mode noise. Electro-magnetic interference (E.M.I.) in the circuit's environment is one source of electrical noise.

Communication Concepts, Inc. - Provide components to the amateur who wants to construct their own gear and to the professional who wants to save money and time in prototyping their circuit design, Filters, HF Amplifiers, Splitter Combiners, VHF Amplifiers, ATV

Intuitive Circuits, LLC. - Intuitive circuit llc is a market leader in dtmf encoders and decoders, cash register surveillance, cash register security, and text inserter products. Amateur televisions ATV products

Eliminate QRM from 6 meters band - The circuit described below will substantially reduce or completely eliminate interference from almost any local source whilst leaving the wanted signal relatively unaffected, even though it may be on the same frequencey by TREVOR, G3ZYY

Improving Heathkit SB-220 - Circuit Improvements for the Heath SB-220 Amplifier

Circuit Improvements for the TL-922 - by Richard L. Measures, AG6K

All American - Distributor of electronic components, ull range of semiconductors (active components), including relays, circuit breakers, transistors, diodes, memory devices, microprocessors, microcontrollers, and other integrated cuircuits, as well as passive components, such as capacitors, resistors, inductors, and electromechanical products, including cable, switches, connectors, filters, and sockets.

HL1INF RF Amplifiers - Circuits, pictures and data about toroids, tubes and home made power amplifiers

Heathkit SB-200 Modification - Tuned input circuit modification by Tom Boza - NE7X

Negative feedback output circuit - Negative feedback is often referred to as shunt feedback in conjunction with emitter degeneration.

DL5DBM 1KW amplifier for 144 Mhz - Pictures and circuit diagramm to build this power amplifier for 2 meters

Build An Audio Speech Processor - When one operates at low power on SSB, speech processing becomes almost essential to get through the QRM. The circuit is a low cost speech processor that will perform well with a minimum of construction effort.

Morse Code Beacon Keyer - This circuit stores a single morse code message as bits in an EPROM chip, the message is sent to a relay which can key a CW transmitter.

DigChip IC database - Provider of electronic components documentation. Offer a reliable tool to find semiconductors components technical information like parts, datasheets, cross reference, obsolete and new circuits.

5 Watt 40 Meters transmitter - This circuit is unique in that it uses a power mosfet as a final rather than a conventional bipolar transistor.

Improvements for TS-830S - Circuit Improvements and Maintenance Procedures for the TS-830S

Circuit Improvements for the TS-430S - by Richard L. Measures, AG6K

Build a Vox Circuit - by Mike Martell N1HFX

Simple Electronic Keyer - A simple keyer which can be built for as little as $6 with some junk box parts. Although this circuit is not a true iambic keyer, it is capable of producing perfectly sounding CW.

Easy Morse Code Keyer Circuit - based on the famous Curtis family of morse keyer chips and has a proven record of dependability.

50MHz-Transverter 10m/6m from DK7ZB - This transverter was built in 1994, a discription in three parts (german language) for DOWNLOAD as PDF-files. Circuit, printed-boards and layouts in the files