GM3SEK's Amateur Radio Technical Notebook


Download The VHF/UHF DX Book - click here



RF Power Amplifiers

The Triode Board
PC board for Triode PA control and protection
Download the complete Triode Board Instruction Manual

The Tetrode Boards
PC boards for Tetrode PA control and protection
Download the complete Tetrode Boards Instruction Manual

We have supplied well over 2000 Boards and Kits in the past 20 years to customers all around the world.

However, these products are nearing the end of their design lifetime and some parts are becoming harder to find,
so we are giving a whole year's notice that the Tetrode Boards and the Triode Board will be 'retired' from the market by the end of 2019.

Support for existing customers will of course continue beyond that date.

Order online, direct from the designer

Power Amplifier Design and Operation

Clean Signals

Tube PA Design and Construction

Sequencing and Relay Switching

RFI Filters



If you have been looking for a copy, your wait is over!

Download a free digital copy of the 2nd Printing, 1995.

Front Cover

Please read the 2017 release notes on page iv.

Corrections and updates


The DG8 - a low-cost, high-performance masthead preamp for 2m

As published in Radcom Plus, issue 1.


VHF/UHF Long Yagi Workshop

VE7BQH Yagi Performance Tables Updated regularly
The 'world standard' benchmarks for Yagi performance on 50MHz, 144MHz and 432MHz.

Stacking Yagis for the Same or Different Bands

Optimize Your SteppIR 3-Element Yagi for 6m
Two dedicated 6m elements will make your SteppIR come alive.


DUBUS - the 'must read' magazine for serious VHF/UHF DXers


In Practice

Thanks to everyone for reading and contributing to this column since 1993.

There will be no more monthly 'In Practice' columns, but these web pages will continue to be updated.

The 'In Practice' pages
More information about ongoing topics

Cost-effective Ferrite Chokes and Baluns
Latest version of the extended Radcom article

More about Ferrite Chokes

"The Problem Solver"

Best of 'In Practice' on the web
Articles and resources of long-term interest

Cumulative Index, 1993 - 2010
All 207 monthly columns, indexed by topic



E-mail GM3SEK

Updated 13 December 2018
Page (c) 1996-2018 IFWtech.
Some graphics (c) DIR Publishing Ltd; (c) Eimac, Inc; (c) RSGB; (c) Svetlana, Inc.
GS35b photo by courtesy of PE1OGF