GM3SEK's Amateur Radio Technical Notebook


This site is rarely updated now. Please bookmark my current site:
GM3SEK's Technical Blog



RF Power Amplifiers

We have supplied almost 2500 PA Control Boards and Kits over the past 20 years, but it is now time to retire these products.

The Triode Board

The Tetrode Boards

Thanks to all the amplifier builders, over the years. Support for your Triode Boards and Tetrode Boards will of course continue.

You can still download the User Manuals from here:
Triode Board
Tetrode Boards

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 5 February 2020
Page (c) 1996-2020 IFWtech.
Some graphics (c) DIR Publishing Ltd; (c) Eimac, Inc; (c) RSGB; (c) Svetlana, Inc.
GS35b photo by courtesy of PE1OGF