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BULLETIN ISSUED BY THE NORTHERM ZCI,TES CF THE P.C. BOX 1010,
WIRELESS INSTITUTE OF AUSTRALIA TASMATIA DIVISICH LAUN CESTQN,
3
. ‘ ‘ TAS,7250,
OCTCBER
VCL, 1 No. 6
1 REGISTERED AT G,P,0, HCBART
for transiission by post as
a Pericdical, CATEGORY B, PRICE 5¢.,
1
T e
Let's takc a look ot the progress of the Ferthern Zene over the last 6
1 ronths; after a1l there have been a fow changes and additions,
-~ The rost cxeiting chenge must surcly be the inercasc in merberships fron
] 18 lost year to 69 this ycar, not counting subscribers to QM not living in the
North, The incrcesc is mainly duc to the Bullctin ORI, backed us by o nenbership
drive, CRM will no deubt teke first place as the bost additien, (considering
we hawe always had en cquiprent storc of sortd, Thanks to an enthusiastic group,
1 we have been able to keep it £illed with ncws and inforrmation,
The cquiprent store has gonc independent and now buys its stocks direcct
1 fron VK3 division anc other sourcces, This has rcsulted in an incrcasc in
turnover fron $242,00 last ycar to #032,00 in the first 6 ronth® of this ycar.
] Cnc change I haven'!t nentioncd - THE MEMBERS, With larger nurbers
attending mcetings and weluntecring for cvery job that nceds doing - that is the
fi
most important chan;ci
Now the question ariscs ~ what of the futurc, Wcll there arc lots of
things we still nced,
Our own clubrcons for instance, whcre we could have our mectings
without thc threat of having te rove,whcrc we could have social cvenings and
cven a Hanshack to usc thce club call VK7MZ,
1 A tuch rorc urgent requircrent is cven larger
al’ss
so how abocut ¥ O U coming along for the next onc,
attendances at cur rectings,
1 eI INN
JOHN, VK7JV,
] OCT, 5th
COMING EVENTS
ITORTH WEST MEETTTG, L/KIN'S HALL, ULVERSTCKE
] 0CT, &th NORTHER! ZCNE MEETING, ADULT EDUCATION BCARD ART ROCM,
€ HIGH ST, LAUNCESTCN,
i OCT. 16th & 30th
OCT, 16th & 17th
YRCS CLASSES AT KINGS MEADOWS HIGH SCHOCL, BLCCX B, ROM 38
JAMBOREE ClI THE ATR
OCT 2nd & 3rd VK~ZL CCNTEST (PHCNE) FROM 10,00 @QIT OCT 2nd TO 10,00
Q1T CCT 3rd.
- OCT. 9th & 10th
oV, 27tk & 28th
VK-ZL CCQNTEST (C,W.) FRCIL 10,00 QT QCT, 9th TO 10,00
GMT OCT. 10%h,
TAFEST IM EVATDALE,
BULLETIN OF NORTHERN ZONES W, I. 4. TAS........OCTCBER, 1971,
PAGE 2
THE GEVERAL MEETI'G of the Nertherm Zonc was holo on Friday Scohtcrber 10th
with an attendance of 33 rerbers,
The Treasurer prescntcd his finaneial report and audited helf yearly
Balance Shecet,
The Scerctary read a letter from the West Lovncestin Boy Scouts gZrocup
requesting holp for the fortheouming Jarmboree on the air, CHRIS'7UX end NORI7ZIT
voluntcered for the job,
PETER 7PD spckc on the possibility of instelling a beacon for 2 and or 6
ncters in Lewncesten, Peter nentioncd that he has had reéent discussions with
VK3 amnatours whe thought it a merwvclous idea, The rcasen being that often the
bands arc open to the I1.W, and net tc the NCRTH and vice verse, PETER 7PD, JOE
7ZGI and BRIA! 7ZBY veluntecrcd te fern a cemndittee to investigate and report,
The weceting clescd at 9,35 and 11 renbers showed the cquiprent they have
constructcd in the nast yecar, Itcrs included e
SPELCH AID I THE FORM OF A MBETRCVQME, ALL WAVE 4 *.ECLIVEL, TRATSISTOR RE-
CEIVER, C.R,C,, TELEPICNE EXCHANGE, 6 METER TRAVSIIITTERS, VIHF CCOVERTERS,
ANTEN A BRIDGE, G.,D,0., 2 METER lTu.NVERTER, FREOUENCY Sfl’T'IWSIZER and
cormercial eoulpmnt
AT THE I’E)’l MEETING DREM 7DK WILL GIVEA TALK AYD SHOW A FILM QI HIS TRIP
AROUI'D AUSTRALIA.
- ) RN
BEV/AN 7CX urzently rcquires idcas, circuits or working rpdels of an
amphorcter deteetor which rust alcrt the driver at least 100 yards before the
specd trap, We belicve Bovan has recently corne acress a device which docs this
cxcept for the 100 yord bit — it's in the formof a man in a bluc uniform,
Fe 3 R K%
JOE 7ZGJ had o diffcroent approach when a pelice cer came up behind hin -
hc accclerated and lost hini This worked until he rcached the next town and
slowed to the usual 35mph 1lirdit, Thore he was overtakan and presented with an
account for $40,00,
FHH KR
TR.EVOR 7TB is building & 6 mocter transverter, If cverything gocs according
to plens we'll publish the c:.rcult for this QR MACHI'E in a futurc issuc,
IR KN K
NOTICED whilc driving to Hobart the ¢ ther day that DOUG 7AB has a spider
guad built and rcady tc go ud,
36363636 35 Fde
ee 3k
IT APPEARS thet the chap vho calibreted the Dumry Load-watineter, which
the Torthum Zonc has been sclling, nade a mistakc in his caleulations end all
powcr rcading should be doubled, However, a ncw conversion table (volts to watts)
will be made ur and sent to o1l thosc who purchascd the kit,
IR NH KK
LOCKS 1likc the Ycasu people really !mow how to trecat their custoners,
TREVOR 7TB hacd scrc overloading problems with his ncew FT101 Tranceiver, At his
request they sent hin sore rocifications consisting of 3 corpletely re-designed
modules being RF stage and 2 mixer stages, also a cmrplctc changce in the acrial
change over sys‘bcv Al this for a totol cost of postage enlyl
FIE AN AN
' S A L E
A SALE will bc held on Saturcay October 9th at the CTH of LET VE720,
102 Frcderick St, STARTTVG 10, 30an,
MLF.
The cquirpnent ornsists of TR&
I Tremardtioms a0 13S L -
Balance Shiel,
The Scerctery read z lettor fron the Yest Lemcestn 5oySecutls sxowp
requcsting hddp for the fortheonming Jarderee on the =ir, CGRIS"UI and FORTIER
voluntcered for the job,
PETER 7PD spckc on thc possibility of instelling a beacon for 2 anéd or 6
necters in Leunccs’ccn. Peter nmentioncd that he has hed rcéent discussions with -
VK3 anateurs whoe thought it a merwvelous idea, The rcascn being that often the
bands arc open to the H.W, and net to the 1ORTH and vicc verse, PETER 7PD, JOE
7ZG] and BRIAN 7ZBY veluntecred to fern a cermmittee to investigate and report,
The mecting clescd at 9,35 and 11 renbers showed the cquiprint they have
constructcd in the nast ycar, Tterms included a
SPELCH AID I THE FOR{ OF A METRCWOME, ALL WAVE 4 RECEIVER, TRAVSISTOR RE-
CEIVER, C.R.C,, TELEPICNE EXCHANGE, 6 METER TRANSIIITTERS, VHF CONVERTERS,
ANTE”TA BRIDGE, G,D,0,, 2 METER HuN%VE\TER, FREQURNCY SYD THESIZER, end
cormereial eoulpmnt
AT THE FEXT MEETING DEN 7DK VILL GIVE A TALX AYD SHCW A FILM O HIS TRIP
ARCUND AUSTRALIA,
- o RREHARA
NNH
BEVAN 7C% urgzintly rcquires idcas, circuits or working rodcls of an
arphorncter detecetor which rust alcrt the driver at lecast 100 yards before the
specd trap, We belicve Bovan has recoently colx across a device which docs this
cxcept for thce 100 yord bit — it's in the form of o man in a bluc uniforn,
36 0K R
SIS
S
JOE 7ZGJ had o diffcrent approach when a pelice car came up behind hin -
he accclerated and lost hin{ This worked until he rcachod the next town and
slowcd to the usuel 35mph lirit, Thore he was overtaken and »resented with an
et WS
account for $40,00,
3RHK
L
TREVOR 7TB is buildinga 6 mctor transverter, If cverything gocs according
SO
to plans we'll publish the c1rcu1t for this QRM MACHINE in a futurc issuc,
s LL
363633636 3036303
MOTICED whilc driving tc Hobart the cther day that DOUG 7AB has a spidcr
quad built and rcady tc go uo,
JE9e3036 3Fode 333
IT APPEARS thet thc chap vho calibreted the Durmy Load-wattneter, which
i
the ortherm Zonc has been sclling, nade a mistakc in his calculations and ell
ei
powcr rcading should be doubled, Joucvor, a ncw conversion table (volts to watts)
will be made ur and sent to all ’cho% who purchascd the kit,
s
ERRAIINHI0K
vt b i
LOCKS 1likc the Ycasu people ru.lly now how to trcat their custoncers,
TREVOR 7TB had somc overloading probleoms with his ncw FT101 Trancciver, At his
request they sent hin sone rocdifications consisting of 3 comlctcly re-cesigned
modules being RF stage and 2 mixer stages, also o cm.plcto change in the acrisl
changce over syster, All this for a t(t“l cost of postage onlyl
eIR KK
_S___A____L____E
A SALE will be held on Saturday October 9th at the QTH of LET VK7B
102 Frcderick St, STARTTMG 10, 30an,
- The cquipnent eonsists of L F, Trensmitters, 30 W licdulator, Valve
converters for 6 noters and 432 11z, 2 Brend lNow VK3 converters for 3 ncters and
432 Mllz including XTALS for 15 Mz I, I‘ Bendix Frequency ncter, Acrials, sparcs
and Tools,
ECRTH UESTERN AFE FCTES
KEWS is rather scarce this ronth]
Cur mecting on 7th Sept, was well =ttencded with 7JV and 7ZAH present, now
sore of our best attenders,
David TS came In weving the latest i,R, Patience recwarded and this saga is
now ccncluded,
A considerable quantity of gear care tc hand for disposal and was handed
round at give-away prices, Merbers whc failed tc attend missed cut cn scre real
goodies!
Sore left-cver iterms of varicus shepcs and sizes finished up in Tony's Q. T.H.
and n=y be yours for the asking if they don't reach the garbage arce first,
We identified cur cld friend John Webster in the rultltude Forgot what
you looked like Jehn,
Scre details of the coming Hanfest werc cutlined and we feel that very
streng suprort will be fortheorming from this Zone, It promises to be an event
tc rerember, IApparently the Zone has discovered a hidden cebaret star for the
Saturday evening shcw, Patrons are advised not to riss this oddity!
LES 7LH is putting the finishing touches to a new 2 netre beam, Does
enyone know for surc how to feed a 6 cver 6 skelcton slot with 300 Ohn feeder,
BRIAN 7ZBE has installed the new Beacon corivlete with a sophisticated
antenna. end fron reperts it is ging very well, Unfortunately the Devenport Council
rissed out cn the scrvices of our Zonc contender, Toc many tuned circuits rescnating
in the wrong placcs Briani
BOB 7ZGR was heard at gced strength frem Penguin way the othcr nicht
with a new 21, rehilc installaticn, Morsc QRM,
The 2M, B nct appcars to be screwhat quiet at present, How abeut serc
activity chaps.
KRT 7RH was proudly derenstrating a ncw H.F. comecreial Transceiver at the
rnceting, It looks the last thing in black bexes, More Q,R.M,
OUR NEXT MEETING IS ON 6th OCTOBER, DO COME ALONG,
One for the Questicns and Mswers:
Is there any test available for a young lad cn 1ORSE CODE, If sc, what
arc¢ the cenditicons and how wuld hc ge abeut it,
C U next Month,
N, W, ZONE,
Fededededese
v
SWERs
The only tests for scnding or receiving rorsc that we kncw of arc in the
forn of PMG and Y"LCS cxardinations,
The PMG cxamination is of ccurse at 10 WPM both receiving and sonding for
A,0,C,P, YRCS havcrorsc tests as part of their S,W.L. certificates with spceds
of 5, 8 and 12 WA,
There arc slow rorsc transiissions et 7,30 BAST cvery night on 3,550 MHz
starting with 4 WPM and increasing to 18 WPM, Pro-rccorded tapes arc available
for hirc fron VK2 divisicn WIA for a very redest cherze., TFor any further
information for eny of the abeve, writc tc the scerctary of your ncarcst
division cr zenc of the WIA,
1l
eR A
@, RiMe
BULLETIN OF NORTHERY ZONES W.I.:. TAS........OCTCBER, 1871.
PAGE 4
ATATEUR TELEVISION 4, T,V. (Part 2)
TESTECUIPMENT,
Like rost.of.€lectronics a 001“'ta.m aromnt of testing gear is essential,
Here arc scne of the rorc necessary cnes for A.T.V,
T C.R.0. (Wideband ~ 6MHz)
2. . Sensitive mltireter ocr V. T,V,IM.
3. - Various Pattern generators:-
(a). Step -generators.
(b) Grating Generator (or crosshatch)
A s
{(c) 2T Pulse & Bar Generator (A luxury but still very handy)
Ly At least twe rrnitors.
(a) Clesed cct. =~ Gorposite Video -Monitor,.
(b) Off air Monitor - Stendard TV with attached UHF converter,
5. Sween Generator,
From the abeve the rost useful is the C.R.0. boing virtually your right
hand man, bcaring in rind that rost of the waveforns in a T V., system consits of
D.C. pfiises end not always A,C. waveforms, A C,R.0. is thus a useful and accurate
nethod of reasuring thesc as it is often the pesk woltage that we arc ccncerned
with, 4 C,R.0. is alsc very useful for bandwidth neasurements in conjunction with
the sweep generater., The step gencrator is used for gamma or linear 1ight ratio
checks in 10 steps from black to white, The grating generator is useful for
lincarity checks, The 2T pulse anc bar gencrator is used for an overall check
of the systen, but is net absclutely nccessary but very nice te have, The clcsed
cct, monitor can be standard T.V. rodified slichtly., The ccrmesite Video signal
(cerplete Videeo plus sync pulses cte,) is crnnected into the input of the video
arp of the T.V. recciver, The T.V, uscd, shculd be cne where the sync pulscs
are taken after the videc arplifier,
The other cbvicus methed of testing the overall perfermance of T.V.
system is by use of a standard resclution chart (Tcst Pattern) in cenjuction
with a flying spot scanner or live T.V, Corera, The usc of the Test patiem
when corrcectly interpreted, can yicld a great meny things such as frequency respemse,
Iike st of
1. C.R.0. (Widebend — 6MHz) wod
4 wrn v~ T 1o
..20 . Sensitive mltireter or 'V‘ T.V,'i{,
3.. . Various Pattern generators:-
(a). Step -generators.
[
(b) Grating Generator (or crosshatch) [
(c¢) 2T Pulsc & Bar Generator (A luxury but still very handy)
Loy At least two ronitors. [
) (a)
(b)
Clecsed ceb. - Corposite Video -Monitor,
.
Off air Monitor — Stendard TV with attached UHF -converter,
L
5. | Swclep Generator, . l
Fron 'the abeve the rost necful ,iS. the C,R.0. becing virtuelly your rizht :
hand men, bearing in rind that rost of the waveforns in a T\ systen consits of '
D.C, pfiises end not always A,C. waveforrms, A C.R.0. is thus a useful and accurate l
nethod of reasuring thesc as 1t is often the pesk wltage that we arc ccncerned
with, 4 C,R.0. is alsc very useful for bandwidth reasurenents in cenjunction wifh I
the sweep generator. The step gencrator is used for garma or linear light ratio
checks in 10 steps from black to white, The grating generater is useful for l
lincarity checks, The 2T pulsec anc bar gencrator is used for an overall check l
cf the systen, but is nct absclutely nccessary but very nice tc have. The closed
cct, ronitor can be standard T.V. mdified slichtly. The cconesite Video signal
[
(corplete Videe plus sync pulses cte.) is crnnected into the input of the video
arp of the T.V. recciver, The T.V, uscd, should bc cne where the sync pulscs L
[
are taken after the vicec arplifier,
The other cbvicus methed of testing the overall perfermance of T.V,
systen is by use of a standard rescluticn chart (Tcst Patiern) in conjuction I
with a flying spot scanner or live T.V. Corera, The usc of the Test pattern
when correetly interpreted, can yicld a great many things such as frequency respense, l
nhase relaticnships, garia and sc on, Mest of the abeve seems a lot of cquiprent l-
to have but they can be gradually acquired as 1like any cther test equiprent,
Next tirc I hene te touch bricfly on the closed cct, cencept, TONY VE7:X [
G. R. M,
BULLETIN OF NORTHERY 7CNES W.I,A. TAS........ OCICBER, 1971,
PAGE 6
( Continued from Sentember Issue) (Copy from AMSAT Iewsletter)
AVHTDED TECTINTCAL PROPOSALFOR AT ATS-G SYNCHRCONQUS AMATEUR RADIO TRANSPONDER
EYPERIMENT
PREFACE
The SYI'CART experiment employs a low~-nower linear repeater designed for
operation aboard the ITASA ATS.G Apnlications Technology Satellite with small
amateur radio stations on the ground. The transponder will consume less than
twenty watts of prime power from the spacecraft and will weigh approximately 5
nounds. The package will be designed to operate within the presently allocated
two meter and seventy centimeter amateur bands,
1, MISSION OBJECTIVES
The SYNCART experiment is designed to use stations in the amateur service
to provide cducational training, "bush!" commmications to medical centers in
isolated areas, The repeater will also be used for multiple access cxperiments,
a satellite-to~home voice and slow scan TV broadcast experiment, and possibly a
space~to~space amateur satellite rclay experiment, All of these experiments will
involve the use of small amateur radio stations as earth terminals, but will
provide services to many outside the amateur commnity itself, (At this point
our proposal went into detail describing each of the uscs listed above,)
2, SWCART DESCRIPTICL
SWICART is a rmlti-~channel, low power-consumption linear repeater designed
for operation in the amateur radio service in the international portions of the
amateur two meter and seventy centimeter bands, The repcater will be designed
to interface with ATS-G ipolications Technology Satcllite according to specificaticns
to be developed jointly with the NASA ATS Project Office, The prototype and
flight hardware will be furnished to NASA by AISAT on a neon-funded basis, The
renpeater will be designed to consume less than twenty watts of prime nower from
the AST-G spacecraft, and is intended to be available for continuous operation
-
by amateur users; except during eclipse or other such times when cemancs on the
ATS-.G power subsystem by cther experiments may requirc it to be operated in a
reduced power rode or to be shut off temporarily.
The repcater will be designed to operate within input (uplin®) signals
between 145.75 and 145.95 MHz (i,e, with a 200 KHz bandwidth) =nd will re-
transrmit thesc signals between 432,1 and 432,3 MHz with an RF nower output of
20 watts PEP, 5 watts average, This repeater RF output power level will be main-
tained by an autometic gain contrel circuit which will be controllable from the
ground to also provide a low-power rode,
The SWiCART rcpeater will be controlled by greund command through the
repular ATS.G NASA cormend systen, It is expccted that no rore than eight cormand
functicns end siz telermetry functions will be required to centrol and ronitor
the SYNCART experiment,
The thirty-feot aperture of the parabolic reflector planned for ATS.G should
prove ncarly ideal for SYWNCART, providing gains of xpjwrommstely 18 dBi for both
the up and dewn-links, and providing full carth disc coverage, The resultant
EIRP should be in the neighborhcod of 30 dBW (one kilowatt) yielding sigmal
strengths on the ground corparable to those achieved with the VHF repeaters on
the ATS-1 and ATS.3 Appliceticns Technology Satellites,
The SYNCART lincar repcater will emmley the Menvelope eliminaticn and
restoration® as developed for AMSAT.OSCAR-B te achicve high efficiency class C
operation and rctain lincarity, It will be designed te hendle 20 te 50 simidi=mecus
single.sideband, telegraphy or telctype signsls in its 200 KHz bendwicth, Growm&
station EIRP of 1kw should produce full repcater output and give 2 30¢B SA ratic
in a ground recciver with a 6dB noise fipure, 13dBi antenna gain and 2KHz Gfmflmffi.
The SYNCART package will include a low-power elge-cf-band beaccn which sdll
be keyed in Merse code with ressazes stored by a "CCDESTOREM™ resszge storage wmmd®
similar to hardwarc dcveloped for “AMSAT-0SCAR-B, This will pernit bulletins am@
- messages to be stered in the satellitc fer pericdic retransmission in lorse cofes
rw-“f‘ 4
It is envisicned that the SYW CART rencster will he ohWlo +- —-m-
twentywatts of pmmm&‘mfl; 1 -
sounds. The packaze will be designed %o operzte within the m
two meter and seventy centimcter amateur bands,
1, HISSIOE OBJECTIVES L
The SYNCART experiment is designed to use stations in the am=teur serwice
to provide educational training, "bush® cormumications to mediczl centers in
isolated areas, The repeater will also be used for multiple access experiments,
a satellite-to-home voice and slow scan TV broadcast experiment, and possibly a
space-to-space amateur satellite relay experiment, All of these experiments will
involve the use of small amateur radio stations as earth terminals, but will
provide services to many outside the amateur commmity itself, (At this point
our proposal went into detail describing each of the usces listed above,)
2, SYCART DESCRIPTICI
S CART is a multi--channel, low power-consumption linear repeater desimed
Ve
for operation in the amateur radioc secrvice in the international portions of the
amateur two meter and seventy centimeter bands. The repcater will be designed
o
to interface with ATS-G Apolications Technology Satellite according to specificaticns
o Ve S
to be developed jointly with the NASA ATS Project Office, The prototype and
flight hardware will be furnished toc NASA by AISAT on a nen-funded basis, The
repeater will be designed to consume less than twenty watts of prime ncwer from
the AST-G spacccraft, and is intended to be available for continuous operation
eP
by amateur users, except during eclipse or other such times when cemancs on the
5
ATS_G power subsystem by cther experiments may require it to be operated in a
B T
reduced power rode or to be shut off temporarily.
The repeater will be designed to operate within input (uplin“) signals
between 145.75 and 145,95 1Hz (i.e. with a 200 KHz bandwidth) snd will re-
transmit thesc signals between 432,71 and 432,3 MHz with an RF nower output of
20 watts PEP, 5 watts average., This repeater RF output power levecl will be main-
tained by an autonetic gain contrel circuit which will be controllable from the
Ao
ground to also provide a low-power rode,
The SWICART rcpeater will be controlled by greund command through the
regular ATS.G NASA cormand syster, It is expccted that no rore than eight corrand
functicns end siz teleretry functions will be required to control and ronitor
the SYWCART experiment,
The thirty-fcot aperture of the parabolic reflector planned for ATS-G should
prove ncarly ideal for SWCART, providing gains of approximately 18 dBi for both
R TR
the up and down-links, and providing full carth disc coverage, The resultant
EIRP shcould be in the neighborhood of 30 dBW (one kilowatt) yielding signal
T
strengths on the greund corparable to those achicved with the VHF repeaters on
the ATS-1 and ATS.3 Applicaticns Technology Satellites,
TT Y T L
The SYNCART lincar repncater will emley the Menvelope elinminaticn and
restoration" as developed for MMSAT.OSCAR.B to achicve high efficiency class C
opcration and rctein lincarity, It will be designed to hendle 20 to 50 simultenecus
sy
single.sideband, tclegraphy or teletype signsls in its 200 KHz bandwidth, Ground
station EIRP of 1kw should produce full repcater output and give a 30dB SA ratio
in a ground rccciver with a 6A4B noise figure, 13dBi antenna gain and 2KHz bandwicdth,
The SYWCART package will include a low-power ecge-ofwband beacon which will
be keyed in Mersc code with ressazes stored by a "CCDESTOREM messoge storage unit
g simlar to hardware developed for AMSAT.OSCAR-B, This will permnit bulletins and
| ressages to be stered in the satellite for pericdic retransmissicn in llorse code,
It is envisicned that the SYWCART repeater will be able to use antenna feeds
planned for the ATS-G 136/148 Mz teleretry and cormand systems for receiving the
146 MHz uplink sisnals, A separate feed will be required for the 432 MMHz SYNCART
a8 2,
transru’c’c:.nb antenna, and it is expected that circularly polerized fourteen-inch
cressed dipeles will be suitablc for this nurnose,
.
TTETT
BULLETII" N m
OF NCRTHER T
ZCNES nr
W.I,., T
T AS........CCTOBER, 1971.
IXGL
J. 7
oW DOES IT WORK: A
s BALATCED .A VCDULATOR
e18 et
‘ T
I+
—
DOUBLE SidDEBAYD
OuUTPUT
—
T2
UDI O % Q }
IMNPLT
sl
|
|
|
R
HT +
RF. WNPuT
You may say, why describc o valve typcl Cn the surfacc this circuit ney look
a littlec cciplex, but with o fow nminutes recading I think you will agree that it
is o straisht fervard cxlonaotion te o fundanental cireuit,
The contrel grids of hth valves in the rodulator arc connceted tozether
and both rcccive the rof carricr siymal frew the provicus oscillator., The plate
of cach tube, however, is connccted to cppositc cnds of the prinary winding of §
the output trensforrncr T{, This ncens thot the plote currcnts of cach tube flow
through thc output transformer in the oppositc dircetions, with the net cffect
that their magnetic ficlds cancel coch other ond ne cutput carricr sinal is
develoned ccross the sceondary winding,
Thus, since cach modulater tubce rceeives the sarc input, ond produces
no nct resultent carricr ocutput, the carricr ncver appoars in the output circuit,
fudio veltages arc anplicd te the modulator tubcs through another trans.-
formcr T2, which brings thesc volteges to ghk, screen grids of the valves, Thoe
cudio VCl'tJ.'Cg on the scrcen grids arc 1807 out of the phasc with cach othcr,
(180° phasc diffcrence acress o contre tepped inductor), Thus, whon the plate ,
currcnt of onc of the valves is made to inercasc by the audic modulaticn wvoltage,
the platec current of the other tubce is deercascd, This wnbalance will couse r-f
weltages to eppcar across the sceoncdary of T1 end thesc r-f woltages, varying
at an auwdio rate, will bc thc upper and lower side-bands, Therc will be no
*
u
carricr present, however, sincc thc redulator is balanced for the carricr, It !5
is not belanceé focr the sidc-bands and these do develop, |
V'"?
A5
P‘—T HATCH CO=--L I‘:Ll‘tCI‘. As
;lt;l.l gntc ]:;csm._lc for snwnc to cxniter 211 the
‘ 1 'l:li:rmcnctmda]l*‘xtx So
p acselhing oxwit tixsc
efrmrcr o™ S 7
HOW DOES IT WCRK: A
ei HCDULATCR
BALATCED e
> DouTbTs-} S idE BAYD
OUTPUT
T2 7
ALDIO TRT
INPUT Zu pfcoulea
eaemsemeseree? |
R
HT +
RF. NPT
You nay say, why describc o velve ty)cz Cn the surfacce this circuit may look
i tle cciplex, but with a foew ninutes reo n‘u T think you will agrec that it
o straisht fervard cxlonaotion te a func’_a
wntal circuit,
The contrel grids of beth valves in the mdulator arc connceted tozether
and both rcceive the r—f carvicr siymol frew the provicus oscillator, The plate
of cach tube, however, is connccted to "0'-)ositc endg of the prinary windingof
the output transforrcr T1, This neans that the plate currants of cach tube flow 1
through the output transformer in the oppositc dirceticns, with the net cffect
that 'bhblI‘ magnetic ficlds cancel coch cther end ne cutput carrier sitnal is
developed ccross the scecondary winding,
Thus, since cach modulator tube rceceives the sarc input, and produces
no nct resultent carricr ocuthut, the carricr ncver appears in thc output circuit,
fudio veltages arc applicd fe the rodulator tubcs through another trans.
forncr T2, which brings thwc voltascs to uhu scrcen grids of the valves, The
audic voltages on the scrcen grids arc 180° cut of the nhasc with cach other,
(180° phasc diffcrcence across a coentre tapped inductor)., Thus, when the plate
currcnt of cnc of the valves is mnde to inercasc by the audic modulaticn vcl‘turo
the plate current of the other tubeis deercascd, This wnbalance will cousce r-f
veltages to appear across the sceendary of T1 ond thesc r—f woltagee, varying
at en avdio ratec, will bc the upper and lower side~bands, Therc will be no
carricr prcocnt, however, sincc the redulator is balanced for the carricr, It
is not belanced for the sidc=bands and thesc do develop,
nceds I E L P!
I/ PEARSQN 7XD As VK7 INTRUDER VATCH comcrdinator, As
Ian sald on the breedcast it is te _ for anvenc to reniter 211 the
i ble for
bands at any onc tine or for that mattcr renitor
i eny cnc band all 'th(; tinc, So
here is your chance tc help Ian and at the samc time do scercthing alxut thosc
intruders instcad of gruwbling ebeut ther, Fill in en intruder ry,_wr'c forn and
forward it to Ian, Forms arc obtainablc fron your zenc scerctary,
E3363KK
E
ok
e
FOR SALL
1 = CERCA PUASTG DiITER UITH 459 VFC, COVERS 14011101, COMPLETE VITH
MANULL . 1100 00.
PARTLY BUILT COIMMINICATICH RECEIVER WITH GELESO FRONT END ALL CCHPCNETTS
110UNTED, ILEDo VIRII'G . ©35,00,
102 TRATCEIVER MODIFIED WORKS WELL €07 FILIAL COMPLETE WITH CH'TRE LOADED
WHIP 440,00,
X HATCOCK VK7KI,
If you would like to BUY or SELL
Address .. any equipment write the details
in the space below and attach to
@ the notice board at the HAMFEST.
CALLSIGN.,. “Phone Home
BRING ALONG EQUIP., TO BE SOLD
BUus oo,
@
REGISTRATION FEE Single $3-50 $o .
Fomily or Double$5-00 §..
..
SUNDAY ORLY per person e AN N R A T S
o
Please find enclosed cheque for$§.
@
A small number of tentative bookings have =
been made at Rubina Joy Guest House and
Travelodge Motel.
cut along l3ne
Bookings required at._
NBMO ib
Motel/Hotel/Guest House for .persons
Calleign
.
, Doudle [[] single [| Femily L
e s W A A I AW A .S i Sy TRMo W ST S S NPT 4
Camping is available at the Evandale
s 70 U I U N AP WA I T AT U T PPSO S YST NS WDAW WA eT
Show Ground for a small fee. .HERE IS a circuit for a 2 M SNIFFER which
I will require Caravan/Tent Site would be suitable for 2 Sniffer Hunt.
Power required Yes/No
®
3 will have gear for TX HUNTS on :~-
W/ *8H R1 0C170 etc.
BF115 Rev.Pol.
52 AM netD FM chBD 40 MD 2MsnifferD
2N3564 " 1"
RFC "
Please make cheques payable to := 24T .4 D 26SWG
W.I.A. Northern Zone, P.0O. Box 1010,
: Launceston, TAS.
L la ’é 01 T
&
Further informetion can be obtained from :- . £ A.F.AMP
B.Yeoman 918288 R.Emmett 444181 Interstage
K.Henricks Bus. 321208, Home 469772 X tran. radio
R
L1 137.4"D T.C.W.
~-
STD AREA CODE
s MtB o S T
" "
003
L2 3 AT‘
C1 2~10 ceramic screw
— Please Refurn —
oa0T e T
further info. in June QRM .
The Wireless Institute of Australia, Tasmenian Division
wishes you and your family to attend the annual HANMFEST
to be held on the 27th and 28th of November, 1971.
AT THE EVARDALE MEMORIAL HALL Carphone Checks
This will be an attempt at & new style of hamfest which PAN
Have your carphone checked f«
hes never been tried in Tasmania before but is guite freguency, power output and receiver sensit:
common on the mainland,
For this type of Hamfest to be successful it depends on Equipment Display
a large number of participants, so we hope to see you Home Constructed & Commerc!
at EVANDALE ON THE 27th and 28th of NOVEMBER 1971, If you have built anything, or oought anythi
which could be interesting to other members,
Hamfest Committiee, bring it along for display.{(Displey both day
“ Trading Post
Will continue for both days, hay
Programme anything you wish to buy or sell?
Cabaret
%ALX IN CONTINUOUS FROM 1200 HRS ON SATURDAY 2Tth Recorded Music, and items by members
by THX. Any acts that might like to voluntee
Fold eleng /i lina
VHF +~-- Fil chB net, AM 52 MHz net (or be volunteered by freinds) will be welcc
HF ——= S$5B-40 M TX Hunts
i%ATURDAY 1300 hrs ===——-- Registration To be judged on a time milage basis.
Rag Chew Traunsistor Radios OK for D¥F Hunt ¢
Equipment Display Prizes
‘ Carphene Checks Will be awarded for:-
Trading Post TX Hunts
1800 = 1900 =w==-- Buffet Style Dinner Competitions
(meal provided) Best item home constru
equipment.
2000 hrg =m—we--— Cabaret Hamfest Style Data Sheets
(refreshments
- provided) Will ve available free of charge.
: Supper
.SUNDAY 0930 - 1000 hrs W.I.A. Broadcast
1000 - 1100 " Yes/No chB & 52kHz TX Hunt
1115 -~ 1200 " VHF Directionsl
e - chB Fox Hunt
70‘Rt'anx.
" Barbecue (meal provided) X .
1215 - 1300
1345 - 1445 " DF Hunt 40 W 144 MHz 3 Element Yagi
Suitable for VHF Fox Hunting
1500 mmmm—a———— Prize Giving and Coffee
Auptralin, Tasmanian Division
wily to attend the annual HAMFEST
b 28th of November, 1971.
VITVHISAV J0 TIONLTISNT SSTTHIIM
su0y uxsyjzIoN W'H*'D
VANDALE MEMORIAL HALL Carphone Checks
Y at a new etyle of hamfest which ve your carphone checked for
s Tasmania before but is guite frequency, power output and receiver sensitivity.
| | 40 be successful it depends on Equipment Display
\é?‘jpntl. 80 we hope to see you Home Constructed & Commercial
b and 28th of NOVENMBER 1971. If you have built anything, or oought anything
which could be interesting to other members,
Hamfest Committee. bring it along for display.(Display both days.)
bl Trading Post
gramme
Will continue for both days, have you
anything you wish to buy or sell?
Cabaret
OM 1200 HRS ON SATURDAY 27th
A1H3uUoy
Recorded Music, and itemsDby members lead
Fold a/gng’_» i fine
by THX, Any acts that might like to volunteer
o=IM chB net, AM 52 NHz net {or be volunteered by freinds) will be welcome.
= U8B 40 M TX Hunts
oe et i Regi stration To be judged on a time milage basis.
utiaIng
Rag Chew Transistor Radios OK for DF Hunt on 40 N,
Equipment Display Prizes
Carphone Checks Will be awarded for:i~
Trading Post
NOISTAIO NVINVHASVLI
TX Hunts
Competitions
§00 ===~ Buffet Style Dinner
(meal provided) Best item home constructed
equipment.
| wmmwmm— Cgpbaret Hamfest Style
e e eoo,
(refreshments Data Sheets
- provided) Will be available free of charge.
) &
Supper
000 hrs W.I.A. Broadcast Boom 1’5 tvbing
"
Elements
4 " 2. s
o " Yes/No chB &fi?ZMHZ TX Hunt
200 " VHF Directionsl
i = chB Fox Hunt
70fimnx
Barbecue (meal provided)
Zrdng
300 "
®
ey " DF Hunt 40 M 144 NHz 3 Element Yagi
Suitable for VHF Fox Hunting
e ———— Prize Giving and Coffee
GUIDEw HAMFEST
SITE
MORIAL HALL
Nov. 27 & 2
EVANDAL_EJ
ee