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Microwave Know How
for the Radio Amateur
Edited by Andy Barter, G8ATD
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mRSGB
Radio Society of Great Britain
Published by The Radio Society of Great Britain, 3 Abbey Court, Fraser Road,
Priory Business Park,Bedford,MK44 3WH.
First published 2010
© Radio Society of Great Britain, 2010. All rights reserved. No parts of this
publication may bereproduced, stored inaretrieval system, ortransmitted,inany
form or by any means, electronic, mechanical, photocopying, recording or
otherwise, without the prior written permission of the Radio Society of Great
Britain.
ISBN:9781905086563
Publisher's note
The opinions expressed inthis book arethose ofthe authors and not necessarily
those of the RSGB. While the information presented is believed to be correct, the
authors, the publisher and their agents cannot accept responsibility for the
consequences arising for any inaccuracies or omissions.
Cover design: Kim Meyern
Production:Mark Allgar, M1MPA
Typography: Andy Barter, KM Publications, Luton
Cover photograph kindly supplied byVHF Communications Magazine
Printed inGreat Britain by Page Bros of Norwich
Acknowledgements
The articles in this book have been supplied by radio amateurs from around the world. The
editorwould like tothank the following people and organisations fortheircontributions:
Ralph Berres, DF6WU
Kent Britain,2EOVAA/WA5VJB
JOhn Fielding,ZS5JF
JoseGeraldoChiquito
Dom Dehays,F6DRO
Stephen Hayman,ZLHPH
Sam Jewell,G4DDK
EdJohnson,AD5MQ
Michael Kohla,DL1YMK
Gunthard Kraus,DG8GB
Alexander Meier,DG6RBP
Roger Ray,G8CUB
Franco Rota, 12FHW
MatjazVidmar, S53MV
Paul Wade, W1GHZ
Henning CWeddig, DK5LV
DrJohnWorsnop, G4BAO
RadCom
UKW Berichte Magazine
VHFCommunications Magazine
Scatterpoint,the magazine of the UK MicrowaveGroup
VHF Communications
Magazine
• Constructional and theoretical articles on all
aspects of VHF, UHF and Microwaves
• Published in English since 1969
• Available by annual subscription
• Kits and PCBs available for most
constructional articles
Web site
www.vhfcomm.co.uk
• Subscribe on line
• List of overseas agents
• Downloads of some past articles
• Search or download a full index of the
magazine since 1969
• Links to other interesting sites
Back Issues
• All back issue available as real magazines
CommunicationsMagazine
or photocipies
Adecadeof
The
magazines
• Back issues on DVD, a whole decade of
magazines on each DVD
• Binders to hold 12 issues (3 years of
magazine)
K M Publications
63 Ringwood Road, Luton, Beds, LU2 7GB, UK
"feIlFax: +44 (0) 1582 581051 email: [email protected]
Contents
Chapter Title Page
1 Antennas 1
•Weatherproofmicrowave antennas
•6cm antenna
•Vivaldi antennas
2 PowerAmplifiers 47
• 1W power amplifier for 9- 11GHz
•23cm amplifier
3 Measuring Equipment 59
• Improving Harmonic response of the HP8555A
• 1OMHz- 10GHz noise source
• Noisefactor measurement with older spectrum
4 Filters and Design 97
• Interdigitalcapacitors
• Bandpass filter for microwaves
• Hybridcoupler
5 Modifying Commercial Equipment 127
• Eyal Gal 21.2 - 23.6GHztranceiverfor24GHz
•Converting the Cenager7HGz modulefor 5.7GHz
• DXR 700 conversion to 5.7GHz
• Using EyalGal 11GHz transverteron 10GHz
•24GHz White Boxes
6 Converters 143
•S Band Receive Converter (uses aYIG LO)
• 144MHz DownConverter
7 Oscillators 161
• DDS using the AD9951
oscill~tor
• MMIC experiments
Index 177
Preface
Ithas beenfive yearssince Iedited Microwave Project2.Since thenthe devices and equipment
available to amateurs interested inthe microwave bands has continued to increase.This book
contains some of the things that are being used right now and some the surplus equipment that
has come onto the market that can be modified for use onthe microwave bands.
The articles on surplus equipment have been taken from Scatterpoint,the magazine of the UK
Microwave Group, this is a very active group an I recommend that any amateurs in the UK
shouldget along toone ofthemeetingthat are held aroundthe country to see how useful being
part of this group can be to get the most out of the microwave bands.There are similar groups
in many othercountries that Ian surewould bejust as helpful if you do not live inthe UK.
So that readers will not think this isjust a face-lifted version of the earlier Microwave Projects
books it has beendecided to give this book a new more descriptive title.
Many of the articles require a PCB, the artwork inthis book is not reproduced to exact size,so
if you are going to make you own PCBs please take care to scale the artwork correctly. I
recommend that you take an easieroption because most of the authors cansupply PCBs and I
have included contact detailswhere possible. Many ofthe contacts areemail addresses orweb
sites, unfortunately these have a habit of changing, they were current at the time of editing
(January2010). Ifyou havedifficultieswith PCBs,finding components orcontact details please
contact me and Iwilltryto help.
Andy Barter,G8ATD, Email:[email protected]
Chapter
Antennas
In this chapter: • Vivaldi antennas
• Weatherproofmicrowave antennas
I
• 6cm antenna
ntennas are one of the features of a microwave station that differentiate it from other
frequencies. We areluckythat incredible gaincan beachieved andthey can beplaced at
many wavelengths above the ground with ease. Something that makes amateurs
operating on other bands very envious. \
Weatherproof antennas for UHF and lower microwave frequencies [1]
Radio amateurs,weather effects and antennadesign
Quite frequently, radio amateur antenna design is limited to a few popular antenna types.
Directionalantenna designs are usually limited to Yagiantennas for the lower frequencies and
parabolicdishes for the microwave frequency bands. The operation of aYagi antenna is based
on a collimating lens made of artificial dielectric like rods, loops, disks or helices. The basic
designgoal ofallthese slow-wave structures istoachieve the maximumantenna directivitywith
the minimum amount of material(metal). '
The situation isactually madeworse with the availabilityofinexpensiveantenna simulationtools
for home computers. The latter provide designs with fantastic gain figures using little hardware.
Unfortunately, these results are barely useful in practice. Besides impedance matching
problems, such designs are extremely sensitiveto manufacturingtolerances and environmental
conditions: reflections from nearby objects and accumulation of dirt or raindropsonthe antenna
structure.
The operation of a 2m (144MHz) Yagi with thin rods (or loops or helix) antenna will be
completely disrupted if snow or ice accumulates on the antenna structure. Raindrops
accumulated on theantenna structure will completely compromise the operation of a 23cm
(1.3GHz) or 13cm (2.3GHz) Yagi antenna. Manufacturing tolerances limit practical Yagi
antennas to frequencies below about 5GHz.
Professional VHF Yagiantennas use very thick rods to limit the effects of snow and ice on the
antenna performance. All professional Yagi antennas above 300MHz are completely enclosed
inside radomes made of insulating material that is transparent to radio waves. Since any
radome includes some dielectric and the latter has a considerable effect on any Yagi antenna,
aYagi antenna hasto becompletely redesigned foroperation inside aweatherproofenclosure.
Ifsome natural dielectric (radome) isadded,then some artificialdielectric (Yagi rods) has to be
removed to maintainthe same focal lengthofthe dielectric collimating lens. •
Simply speaking, any serious design of a weatherproof Yagi antenna for frequencies above
300MHz is out-of-reach for most amateurs. Fortunately there exist other antenna solutions for
Description:Published by The Radio Society of Great Britain, 3 Abbey Court, Fraser Road,.
Priory Business Park aspects of VHF, UHF and Microwaves. • Published in
