The radio amateur’s VHF manual : a manual of amateur radio communication on the frequencies above 50 megacycles

324 Pages·1968·61.532 MB·English

by  Tilton, Edward P.

The Radio Amateur's
V.H.F. Manual
A Manual of Amateur Radio Communication on the
Frequencies Above 50 Megacycles
BY
EDWARD P. TILTON, WlHDQ
V.h.f. Editor, QST.
Published by
The American Radio Relay League, Inc.,
Newington, Connecticut 06111
COPYRIGHT 1968 BY
THE AMERICAN RADIO RELAY LEAGUE, INC.
Copyright ••eured under the Pan-Am..-ican Convention
International Copyright aeeured
Thi• work ia Publication No. 16 of The Radio Amateur'o
Library, publiohed by ihe League. All righta reHrved. No
part of thia work may be reproduced in any form e:o:cept by
written penniuion of the publiaher. All right• of tranelation
are reeerved. Printed ln U.S.A.
Quedan re•or'f'ado• todoe 1011 dereclto•
Eleventh. Edition
Library of Congresa Catalog Card Number: SS.8966
$2.50 in U. S. A
$3.00 eaowhera
Foreword
Few essentia11y technical works enjoy the enthusiastic response
that greeted The Radio Amateur's V.H.F. Manual upon its intro
duction some three years ago. V.h.f. amateurs of a11 shades of skills
and interests found it what the author intended it to be: ". .. a
book largely about things that work, and the principles behind
them-a distillation of a generation of practical experience in the
v.h.f. realm." The Manual quickly became a best seller, and it bas
remained so to this day.
Perhaps this success is explained by the fact that this is more
than a reference book for the v.h.f. enthusiast. To illuminate the
technical chapters to fo11ow, it includes the first detailed history of
"the world above 50 Mc." ever written. It ex-plores the vastness and
potential of the upper reaches of the radio spectrum, bringing to
many readers a new appreciation of the true worth of this great
radio resource. In terms understandable to the newcomer, yet use
ful to the experienced worker, it discusses the problems every
v.h.f. enthusiast encounters, and spells out practical solutions.
It abounds in equipment projects for the fellow who likes to
build his own gear. This second edition has a number of solid-state
items not available elsewhere, yet there is much that will be help
ful to the man who likes his equipment ready-made. There are
some 70 pages of information on antennas, the worth of which is
well substantiated by the outstanding records made by 'WlHDQ
antennas" in Antenna Measuring Parties held all over the country.
V.h.f. mobile work, techniques and practice for the microwaves,
solutions for the v.h.f. man's TVI problems, simple test gear you
can make and use effectively-these are more of the ways by which
this Manual bas established itself as a major item on the list of
ARRL publications.
In launching Edition One we asked your help in making it a
better book. We got it, in letters by the hundreds, largely fu)] of
praise, but including many helpful suggestions and criticisms.
These were studied carefully in preparing this Second Edition.
As you glance through its pages for the first time, you'll note that
there are quite a few new items. Upon more careful examination,
it will be seen that the entire text has been gone over, word by
word, line by line, to improve and update it in countless ways. We
hope that you'll find it even more valuable than its predecessor.
As before. it is the work of QSTs long-time v.h.f. editor, Edward
P. Tilton, vVlHDQ. Contributions of many other dedicated v.h.f.
men are gratefully ac1n10wledged in the text.
JORN HUNTOON
Newington, Conn. General Manager, ARRL
Ross A. Hull, v.h.f. pioneer, and QST Associate Editor, 1931-1938.
Ross snw the potential of the then-uncharted world above 50 Mc. per
haps more clearly than any other man of his time. The technical excel
lenc.-e of his equipment designs and his enthusiasm in print and in person
fired the imagination of a whole new generation of rndjo amateurs, among
them the author of thjs book. His djscovery and eventual explanation of
tropospheric bending of v.h.£. waves has been called "one of the truly out
standing cxnmples of scientific achievement by an amateur in any field of
human endeavor."
CONTENTS
Chapter 1 How It All Started 7
2 A Vast Resource . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3 Reception Above 50 Mc ....... ... .... ..- . . . .. . 30
4 V.h.f. Receivers, Converters and Preampliliers . . . 44
5 V.h.f. Transmitter Design . . . . . . . . . . . . . . . . . . . . 83
6 Transmitters and Exciters 97
7 The Complete Station ............ ....... ..... 140
8 Antennas and Feed Systems ...... .. ...... ..... 161
9 Building and Using Antennas . . . . . . . . . . . . . . . . . 187
10 U.h.f. and Microwaves 229
11 Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
12 Interference Causes and Cures 293
13 Bits and Pieces 303
Index .................. .... .. ... .... ... .... 317

Chapter 1
How It All Started
Those of us who make the frequencies above This was c.w., remember. You had to chase a
50 Mc. our principal stamping ground tend to wandering signal with a receiver that was
think of v.h.f. as the "new frontier" of amateur touchy beyond belief, even with stable signals.
radio. Actually it is as old as the art of radio But 5-meter gear was made, and it worked after
communication itself. While universal use of the a fashion. When the first pioneers heard one an
upper reaches of the radio spectrum is a fairly other across town they were ready for a shot at
modern phenomenon, some of the earliest work Australia, or Europe. This technique hod
with electromagnetic radiation, and perhaps the brought results before on lower frequencies,
first nctual communication by radio, were on why not on 56 Mc.? s Tlwn came several years
wnvelengths near our present 2-meter band. of largely fruitless effort. There were scattered
The resonator of Heinrich Hertz, and the '11eard" reports, some rather dubious in the
practical appHcations of it by Marconi, oper light of present knowledge of v.b.f. propagation,
ated around 150 ~fc. And if you think that the but rarely was there two-way communication
beam you are using is a recent development, over more than a few miles.
consider the fact that Hertz used a rudimentary By 1928, interest lagged. There were rum
form of Yagi in 1888, and Marconi employed a blings of DX on our new band at 28 Mc. The
parabolic reflector to extend the range of bis DX drive tended to move lower in frequency,
first equipment before the turn of the century. and for about two years the world above 50 Mc.
But Marconi and a generation of radio pioneers was in11abited mainly by experimenters, rather
to follow him moved to the longer waves to than communicators.
achieve greater coverage. The ultra-high fre
Short-Range Phone Does It
quencies lay dormant for 20 years thereafter.
Up to this time, most amateurs were code
The Drive for DX men. Phone was coming in, but it was frowned
ARRL and QST had been in being for nearly on ns wasteful of frequency and was often
ten years before frequencic~s higher than 15 Mc.
were discussed in any detail. Transmitters using
vacuum tubes had replaced spark rigs in the Working at S Meters
early '20s, and the unfolding possibilities of DX By S. Kraa~, Technical Editor
ovnen twuarovuelse anmgtahtse ubres lotow p 2ro0b0e meveeterr hs igchaeurs eidn farde LAmSrTth omU: uwnho rkle d .p.aci:dr fklth.IaJt wotrnd id:mia:':r&y ~Ta 5:::. =:et:.l.1l.1 1:~~ a 5::
quency. Each move upward produced new nt.oe ed2e0d :b:teltl'tott•• tbl-a.aLt epSeicnlael. tchaarte dWm&i!t. <:Om"C:p:Je~d tsKe~t ra.n1d :tgh;trndco.re : n~on ~Ii.~ar~m. uwi~ll
ggmmeioiuarnnaric. cw lTaeatshsi oe of nifnn eDawxlXltiy t,hb m aclnuaolddwm et i hpntoeao ntwwi noeogrpr -ekiinn ni ntw o dto aharyelmdl i1wag4thei-dtMu-erw scc .ohw rmeaens !tlMnwbtOnhoto•oct( f.mra: lk.taa.b :e urt·oot.1 u tbf.ta-.u rtTortot1n. tJb1hrad-led decnr i"t, l~ndd) m"o'ad . S alor tuO t:\\ouhann' c!lidolmb rr t•ey.1.5ete,1r. • ta a fcemtocHtror;whyrsto t am, o. it"n.in:nsar' \o" kd.btrw"otcoou •fno 'ctf g•mril wka ' 5tYb1 Mft-hklw tt5ecam Me h tt~ aa . hitW! n cetayo 2tt.>ui!ur >r.l~bNs0eld-~.et- aun.:nandTNk hoinwonwo ge o Wtcohnamupet i.p .a•ckl.rbetce. toiat 1k)d 'Th tcotlVhlwJ rwCe in C:to uChfJrtlUiklotnr . ttg-watu. h- htoavJa .Ibc.tu o iUyowr& n •t metbh?ae\ l lFt uhletb.l iex2 .,
at 56 Mc. It was widely assumed that if worka wAtl Lube work un.1teadily. cAi rlciuttilte a1stu diny .\Ft'I"Uls . 11h,o ww ilthhl at hWl'!): baicd. dthitei ounm oef.
ble 5-mctcr gear could be built, this band would l alao ad\'lacc:d. uthhe1. a u.Oteo ow1f1 on• tube only. tthhee troabdeio o sfctat1q1uatt.en. c1 chokr1 netded tO nate
nta waaconecl•t .co mdton,t. •t.ill moM To tell wbto tbt Hl (1 OKllt.ttlni: the
be even better for DX than 80, 40 and 20 me
ters had progressively h1rned out to be. r
Just getting there was thought to be the prin
cipal problem. Technical Editor R. S. Kruse
pointed tl1e way in the October, 1924,. i5sue of
QST, with "Working At 5 Meters," perhaps tl1e
first v.h.f. constmctiona1 article ever published.l
In the next few years much QST space would
be devoted to 5-mcter gear, but trying to use it
was a frustrating business. Transmitters were
simple oscillators; stabilizalion of any kind was
all but unknown, and not even considered for
5-meter rigs. Receivers were regenerative detec
tors-hard to get going at all, and tl1en incredi
bly cranky to tune. Oscillators using debased
tubes, mounted bottom-up to reduce lead in
ductance, and receivers with foot-long insulated
tuning shafts to hold down hand capacity, were
the order of the day. The wonder was that hams In probably the first v.h.f. constructional ortido over
of the middle Twenties made gear work on 7 or published, Technical Editor Kruse described a 5·meter
14 Mc., let alone 561 ~.a, ~ oscillotor in QST for October, 1924. The oscillator tube,
The footnol·es refer to the biblioJ',l'nphy at the end of barely visible just lo the right of the tonk coil, wo• o
lbc chnptcr.-Editor. debased C·302 resting bottom-up on its gloss envelope.
7
8 HOW IT ALL STARTED
treated as an unwanted stepchild. Then a few Soon it was found tl1at these two castoffs had
u.h.f. experimenters began modulating their something else in their favor: If stations were
rigs, and unwittingly triggered orr a boom that not too close together in frequency, their trans
was to establish the 5-meter bnnd as desirable mitters and receivers could be operated simul
communications territory in the minds of a taneously. This was "duplex phone," a wholly
whole new generation. new concept. Two hams could converse as easily
by radio as over the telephone, or face to foco.
Duplex wns r111 overnight sensation, with obvious
r«i·- advantages over c.w., nnd the monologue voice
-~ l"\Ci0t cDIL 0: 1\lti:I\) (At" toll fo..-.n technique then used on lower bands.
_ ,._);j._ eoi TO..., ~ 'TUeC a.'-X. The ill wind of economic depression blowing
... across the land had made thousands of hams
_ idle. With much time and little mone)r. they
........ were ripe for a kind of hamming that could be
..... carried on with makeshift gear, largely made
by hand or with parts robbed from discarded
radio receivers. Not only from junk sets, either;
as 5-meter interest boomed, more than one fam
ily's radio listening time was rationed, while the
ham of the house reddened the plates of Typo
45 or 7.lA tubes, lifted from the broadcast set
for service in a 5-meter oscillator. Simple Jow
cost gear; duplex phone; the thrill of something
Autodync receiver used by WBAZL in pioneering 5- new, yet wilhin the rcnch of nearly cveryone
mcter work with WBPK and WBABX. V.h.f. adaptation thesc were magnets tl1at drew countless new
of the supcr·regenerative detector, which wos to popu comers, including the author of these lines, into
lorizc v.h.f. operation in o big woy, was still a year amateur radio in the earlv Thirties.
owoy. From September, 1930, QST. As all through the history of the hobby, QST
struck the spark. The July 1931 issue was fat
The experience of early 5-mctcr phone ex with v.h.f. lures. Technical Editor Lamb had 11
perimenters John Long, WSABX, and E. 0. pages on u .h.f. oscillators,7 some working ns high
Seiler, W8PK, was typical. They were working as 400 Mc., where some farsighted administrator
on 80 one night in the summer of 1030, when had set nsiclc a narrow band for amateur cx
a thunderstorm not far awny made communica perimcnturs. Associnte Editor Ross A:. Hull, who
tion difficult. W8ABX was runnini,: his 5-meter would become one of the v.h.f. man's legendary
ri!{ simultaneously, and when W8l'K listened on heroes, fanned tho Jlnme with down-to-earth 5-
5 he found, to his amazement, that signals were meter receivcrs,H adding reports on mobile re
far clearer than on 80. Here, for the first time, ceiving tests, for good measure. Hull's "Duplex
the 5-meter band was seen to have real worth: Phone on 56 i\lc." in August 9 described more
it would work over short paths with voice, when simple gear, and set forth the operating concept
noise levels, high activity, or other adverse fac that was to build the fire to conflagration pro
tors were present on lower frcqucncies.5 portions.
Receivers were still a bottleneck, however. The urge to work around the world was for
The regenerative receiver, critical enough on gotten; the aim now was to work across town,
nny frequency, was an operntor's nightmare at
56 Mc. Enter here the supcrrcizcnerntive de
tector. Invented years before, the superregen
had not found much favor with mnnteurs.G It
was useless for c.w., and its brond frequency
response and raucous audio quality gave it a
bad name in voice work. But on 56 !I le., where
there was band w;dth to burn, broad tunfog was
almost a blessing.
In retrospect we can see several factors com
bining to accelerate 5-meter interest as ham ra
dio moved into the Thirties. The wedding of
I he modulated oscillator and the supcrregcnera
tive detector would start thini,:s rolling again.
The modulated oscillator sounded nw£ul on se
lective receivers now in use on lower frequen
cies, and it used up more than ils share of high
priority kJlocycles. But there was plenty of room Cover pidure from August, 1931, QST shows the mod·
on 5, and the unstable signal didn't sound bad uloted0oscillator lron•mitter that helped trigger tho 5·
at nil when received on the broad-tuning "rush meter boom of that eventful summer. Two 71 As in o
box." push-pull oscillator were modulated by parallel 47s.