circuit board layout

The 4X4 Slimtenna - Development of the Slim Jim antenna for HF

FJ/OH2YL online log - FJ/OH2YL Online Log ST Barthélemy 2011

KRG Kidderminster Repeater Group - A non-profit organisation responsible for the maintenance of the GB3KD 144MHz VOIP Repeater, and KidderLink simplex gateway, plus the KIDDER packet radio node and GB7PZT bulletin board system.

Scans of Elecraft PCB Boards - Elecraft K1 & K2 PCB scanned top & bottom, for troubleshooting

AFR Enterprises - AFR Enterprises a leading distributor of electronic components, semicondustors, diodes, Resistors, Integrated Circuits across the USA.

Ham Dashboard - Iphone App with list of nearby repeaters in the UK, along with details of input and output frequencies, a map, and a handy bearing arrow for each repeater.

Triode & Tetrode boards - A lot of good things, not for QRP fans.

Transistor PA Biasing - Here is a simple circuit that can deliver the peak base current needed for linear ssb operation

Transistor PA Biasing - Here is a simple circuit that can deliver the peak base current needed for linear ssb operation

Recovering old NICAD and NMHI Cells - Old Nicads batteries and sometimes NMHI batteries usually end up with several cells being short circuit, as they suffer from crystal growth in the electrolyte

Semiconductors - Semiconductors, diodes and transistors, intregrated circuits

RF Dummy Load - The use of dummy load is mandatory for off-air adjustment of the transmitters. Build one.

Circuit Laws - Basic electronic circuit laws

A high perfomance Crowbar Circuit - The MC3423 can protect sensitive circuity from power supply transients or regulator failure when used with an external "Crowbar" SCR.

DC RF Sensing PA Switching - Circuit for dc/rf sensing pa switching from g8mny

PC Board Filters - Offer performance comparable to tin-box filters, and except for being bigger, stack up pretty well with those expensive little helical jobs. You just have to be able to make your own PC boards.

QLF Filter - Microprocessor based interface designed receives a signal from a Morse key, processes it, and re-transmits it to the radio. A microprocessor in the circuit is pre-programmed with a proprietary algorithm which makes a number of measurements and adjustments to the less percise human generated code.

Non-relay instant RF Switching - Coax lines to do the RF switching. The advantages are instant switching, no power wasting DC control circuits.

144 MHz Antenna Pre-Ampilfier - Electronic circuit and components layout fot this VHF Preamp

DRM Demo Receiver - Christoph Petermann DF9CY DRM demonstration receiver project including Circuit Diagram and component list

Bartling RX-40 Receiver - Circuit Diagram and Construction of the Bartling RX-40 Joachim Münch DF4ZS

30 m Band Direct Conversion Receiver - The direct conversion receiver described consists of only a bandpass filter, mixer IC, VFO and audio filter. With only 22 parts, this simple circuit should take a few hours at the weekend to construct.

CTCSS Encoder Board - CTCSS Encoder Board by Eric van de Weyer VK2KUR

Oscilloscope Tester - Circuit to assist in the setting-up and calibration of oscilloscopes

UHF on a VHF Rig - This circuit enables fair copy of strong 444 MHz signals, off a local repeater, using a 2m rig and a 1/4λ 70 cm indoor ground plane antenna.