simple calculator circui

The Field Day Special Antenna - Antenna that's simple, inexpensive lightwiight and easy to install

Bazooka dipole for 70 cm band - Here is a very simple 70cms dipole from Harald PD2HFE, which uses a single piece of RG-213 coaxial cable 34 cms in length.

The simplest phased array feed system that works - How to calculate "phasing line" lengths that actually work.

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

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.

Picture of a multiband dipole  ^pop - Pictures of a multiband dipole, build with simple PVC T and standard electrical wire

A homebrew 10-element 900 MHz quagi - A 10 elements quagi antenna for 900 mhz

Optimizing Inductors - While intended mainly for antenna loading coils, this article also applies to other resonant systems, such as amplifier tank circuits.

Simple double-quad Antenna  ^pop - 2.4 Ghz quad antenna

A Tincan feed for 2.45Ghz  ^updated - Construction details for a simple but effective antenna for 2.45Ghz wireless lan use.

Slotted Waveguide 802.11b WLAN antennas - 802.11b WLAN Waveguide Antennas Unidirectional & Omnidirectional. High gain, Simple construction by Trevor Marshall

A two element yagi bean - Simple gain antennas for the beginner, a 2 element yagi antenna

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

Circuit Specialists - We specialize in pc-based data acquisition systems, test equipment, electronic components, disk on modules, choke and coils, diodes, capacitors and connectors, potentiometers, crystals, resistors, relays

Yagi Modeler Applet - This java applet/application implements a simple yagi modeling code. The initial input is a really trivial 2 elmenent yagi.

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.

Avoid pitfalls when recharging batteries to ensure long life - Portable design - avoid pitfalls when recharging batteries to ensure long life - secondary batteries can be simple devices, but improper charging can be devastating to the user experience.

Constant Current Battery Charger - Constant Current Battery Charger circuit project

Build a simple rechargeable CMOS Battery - An inexpensive rechargeable CMOS battery system that can be built from readily available parts.

Simple Reverse Polarity Protection - This simple modification is applicable to pretty much any 12 volt operated, positive earth equipment. by Chris Cox, N0UK, G4JEC

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.

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.