circuit design

9 element yagi for 2 meters band  ^{updated  pop} - A simple design of a 9 elem. yagi antenna for 2 meters band

LU9DPD Daniel - Homebrew, antenas, balunes, expediciones, circuitos, electrónica, torres, fotos y relatos, todo referente a radioafición, radioaficionados y radioamateur

Choke Balun Designs - In this designs G8ODE explains different methods to builds a choke balun

A Portable Multi-Band Magnetic Loop Antenna  ^pop - Described here is a simple multi-band magnetic loop antenna designed for 20, 30 and 40 metres, but by changing the overall length of the wire coverage of other bands is feasible

Antennas : theory and designs - Thierry LOMBRY, ON4SKY, develops in several long articles all you need to know about antennas, their design and performance, for both amateurs and SWL

DPD Productions - Home of the TrainTenna and MilTenna. Uniquely designed antennas for Transmit or Receive Only, Indoors and Outdoors, Railroad, Aviation, Military, Ham, MURS, GMRS, and other services.

ASTER Teleservices - Telecommunication Infrastructure jobs including the Tower and Foundation design

ON5UR QSL print service - We are hams who design high quality full colour QSL cards. Now we print also full colour backsides on our QSL cards. 1000 cards costs only 82 Euro. For more details write max@on5ur.be``Remember: The QSO is short, our QSL cards are forever !

YagiCAD - A freeware software package for Yagi design. This webpage also contains many sample and standard antenna downloads for experimentation.

Smith chart calculator - linSmith is a Smith Charting program, mainly designed for educational use. It allows defining multiple load impedances (different frequencies), and adding components (discrete components and line sections) in series and parallel. It plots the impedances on the screen, shows the values in table format, and is able to generate publication quality Postscript output.

AmRLog - Palm OS based shareware application by KC6AAB for Amateur Radio Operators. AmRLog is designed for logging mobile radio contacts.

MorseGen - MorseGen is a simple program the purpose of which is to generate Morse Code at whatever speed you feel comfortable reading, for practice purposes. It wasn't designed to be a tutor for those who know no Morse at all, although you might find it useful for that purpose. It doesn't have a feature for sending small character groups over and over, although this can easily be achieved by creating text files containing the character groups you want to practice.

Big Fat Tail Productions - PocketSat is a full-featured satellite tracking application for PalmOS and PocketPC devices. It is designed to be usable by both experienced satellite trackers as well as novices who are interested in knowing when they can simply look up and see satellites.

Defpom's CB Radio Simulator - It is a application which can be used for troubleshooting CB radio faults, by giving a graphical display of the normal operating frequencies generated by various parts of the CB radios circuits, it can help you identify if a frequency is incorrect or even missing. Another good use for this software is simulating possible frequency expansions, as it allows you to choose any frequency that the PLL is capable of generating, so you can see what the radio will allow you to get !

A.M. tutorial - This tutorial is designed to help explain some of the concepts involved in RF power measurement for amplitute modulated signals.

Audio Preamp - Easy circuit that provide good gain to weak audio signals

KB2LJJ Radio Mods Database  ^pop - The KB2LJJ radio mods database offers approximately 12,000 Radio Mod's, circuits and manuals.

Ferrite information - Ferrite Toroidal Cores, Magnetic Properties of Ferrite Materials, EMI - RFI Suppression Design Considerations, Ferrite Beads, Ferrites for RFI Ferrite Cores for RFI Suppression by CWS ByteMark

80m SSB & CW transceiver - The 80m SSB & CW transceiver design is based on an already proven concept used in ATLAS amateur transistorised transceivers from 70's

144 MHz preamplifier with BF981 - Design of a preamplifier for 144 MHz with 1 dB NF and 23 dB gain using BF981. This amplifier is using a low cost silicon MOSFET (BF981 from Philips) to give more than 20 dB gain with around 1 dB noise figure on 2 meter.

23cm dual stage preamp - A modification / combination of the DJ9 BV & I5TDJ 144 MHz preamp designs

Using ferrites for interference suppression - This tutorial is meant to shed some light on the use of ferrites, and also presents some comparative frequency domain measurements both to illustrate some of the points, and to give designers an idea of what they might expect in using and specifying a ferrite component

Regenerative Radio Receiver Circuit - Useful and well thought out regenerative receiver design

WD5HOH Regenerative(Regen) Receiver - This web page describes a small, single tuned circuit regenerative receiver primarily for daylight reception in the 16, 19, 22 and 25 meter international shortwave broadcast bands.

Build A Vector Network Analyzer - The VNA (vector network analyzer) is an essential tool for measuring the complex impedance of a circuit at a given frequency. Article on how to build a Impedance analyzer.