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A @RM-
CULLETIN ISSUED DY THE NCRTHEIN Z(NES CF THE P.C,2CX 1010
WIRELESS INSTITUTE (F AUSTRALIA TASMANIAN DIVISICN LAUN CESTCN ,
TAS, 7250
-, ‘.
'
1 o
O
AUGHST
VCL, 2 NC, 5
REGISTERED AT G,P.C, HCDART
fcr trensmission by ncst as
a Pericdiecal, CATEGTY 3, PRICE 5¢
The W,I,A, Tasmanian divisicn requests the plecasurc of your ccrpany cn T~
the .12th an? 13th cf August for the purposc cof participating in the RD erntest.
It was said last ycer that Tasrania cculdn't have wen even if the average of- - -
the top six logs had been higher, a few calculaticns shew this te be quite
—
true and in fact shows that it was cuite irpessible fer Tasmenia te win unless
L
we can get 50¢ of thce amateur pepulaticn tc participatc, Altermatively we nced
tc increase the average scere per staticn by at least 1009, Either cf thesc
are not likcly tc haspen, Dut with a 1little enthusiasn and a small increase
id beth we may just bc able te nake it, WILL YCU TRY.?
JCHN VK7JV
ELITCR.
FHHH
KA K
MEETINGS
AUGUST 1st - North West Zcne - Lakin's Hall Mlverstene
-~ AUGUST - 49¢n .~ Nerthern Zone - L.E,D. Reenms, High Street, Reem 10,
IR IR I HIRKHR
THE NMCRTHEWN Z(NE Clubrecn Acccunt is grewing steadily:end at the nresent
‘rate we eculé have cur first $1000,00 in the bank by the end cf the year,
Much of the-credit rmst go to Jece Gelsten VK7ZGI who to date, has been.our:
largest eentrituter of cquirment - THAKS JCE - keep up the geod werk! .
¢
A Fhio s ek B 5 dededt
G. R, M,
DULLETIN (F NMCRTHEW Z(NES W.I.A. TAS, AUGUST, 1972
PAGE 2
N(RTHERN Z(NE MEETING
The July rccting was well attended - 32 nresent and apeclcegics fren
TZWX, 7ZLT and Alf, Willis, We were plcascd te have with us scme far flung
rerbers Ian 7218 & Graham 77AQ frem Tevenpert and AL ZLYAN frenm Mecrinna,
Peter 7P°F gove a full rencrt en the reeent Repeater ecnference, Icdeas
frem the ecnfercnce arc subjcet to ratification ; hewever it was rececrmended
by Petc that we invcestigatc the foasibility of using Channcl 3, Present
channel 4 will hc a hetspet with prejected repeaters en M. Maceden and
Sendiges New reccive freoguencics arc te be in use by Neverber 18t, We hepe
te change over as scen as practical,
L request is expected fer the zene te be recspensiltle for crigineting the
Suncay WI). brecadcast, It is hcped that rembers will assist in cffering idcas
and inferraticn te cnsurc o tep-rate preducticn, Transrissicn en the repcater
as well as HF is envisaged,
A réccrflrficndatic:n by the Executive tc allew Institute student mernbers full
zene priviledzes withcut further fic was ax>reved by the July reeting,
Ipplicaticns for student WIA merbership fren T, Pelewy, R. Ducker and
Re Kearle werc passed for sulwissicn te Council,
Chris, 7UX vrescnted the reeting with a errpelling film on the cncraticn
at Ceralec, His frlloewup talk was rest infrrmative,
Vext reeting will e an cquiprent display nisht, Here brew cr cormercial
it decsn't natter - bring it alens, Thesc reetings arc generally the high-
in ¢f the year - yeu help it te bei
pcint ¥
DELIEVE therc arc seven sitting fer ACCP cxars this renth - hest of luck
chaps!
ERR R KRR IR RK K
A CHEQUE fcr $10,00 was rcccived frenm the Fodereticn Irsurance Crrpany, Ten't
ferget this rcthed of beesting cur funds,
AR I RN
RNNNK
PERHAPS a scurce cf clubercen finance is being wasted, How abeut a finc on
rembers net wearinz their name tassi
R TR N A H KA
NCTICEL thc changse in address labels fer last renth's issue, Seers 7JV
is getting scre tyoing »ractise,
.
R IR AR RRA KA R N TR
sk
e
P
A X(UPLE c¢f rnerbers having vehicle treuble with their erpleyer's units- 7ZGJ
rclled his van and 7ZiF Ciscevered his Land Hever's 4-whecl drive was cut of
acticn after being stuck in the sncw cn Iit, Barrcw!
HHIRKKKX
3R33N
PAGE 3
NCRTH WESTZ(NE NCTES
(n 4th July we enjoyed cur best recting fer scveral renths, Numberced
arcngst cur visitcrs were Mi e 72, Wal 7ZVX end Jec 7ZGJ, Alsc 7IT care
aleng tc sul'stantiatc ry ferceast., Torry is ncw heard on 2 netres, and sc
the ganz is grewing, Ten't ferget ladies night en September 5th, so tce up
the babye—sitter, C(ur next mieting en 2nd of fupgust is the fnnual Meeting, sc
ccre along chaps and zet debled in',
It was agrecd that Teny 74X subrdt scre notes for inclusion in the divisicnal
bulletin,
Turins-the meeting, cnce again Roscmary, XYL Trny, entertained some of
the memberst wiecs, Me-thinks thcy ncw leck forword te the rag-chew,
Sere very interesting circuit beards were sizhted on the bench at 7AX QTH,
Maybe TV Teny,
Ken 7XH was cverhecard ruttering Jonenesce during the neeting, Yeou rust
. be getting quitc fluent ncw Xen,
Graharn 7Z40 end Ian 7ZIE have successfully cenverted low band 203 units
te the 144 MHz band with cutput scrcthing cver 20 watts, Very geod effert chaps.!
Alsc I uncerstand that Iap is now rcnitering the band ecntinucusly cn tape.
This shculd preve very valuable in checking rehiles and band encenings.
M™X,
R AANKK
363K
The r,f, scction cf the rcceiver should be aliged as fclleows:-
1. Plug an O~1 nA neter inte the 1st LIM metering sccket and a 25-0-25 ul
neter inte the I'ISC retering sccket,
2. Sct the ncutralising capacitcr (02) tc aprexirmately mic-nesiticn,
3. Conncet the sigmeal gencrater te the acrial conncetor, Tune the gencrater
tc signal frequoncy as indicated by zerc reading in the contre~zerc nmeter,
4o Screw the slug of L5 inte the wesiticn of maximun inductance and adjust
the signal input lcvel te prccduce a reading cf anproxinately 200 uld in the
1st LIM ncter,
5. Tunc the sluzs in L6, L3, L2 and L1 (in that order) for peok recadings in
the 1st LI nmcter, rcducing the signel in-ut level as neccssary te nmaintain
the meter rcading in the viecinity of 200 ud.
6. Tune the slug in L5 fer maxirun reading in the reter,
B §861§fih off and disccnnect N3,
.
Switch cn agein and increase the input level to
T -
( ecntinued)
8, Neutralise the r.f, stage by carcfully adjustinz C2 for 2 2ip in the st
LIM nmeter recading.
O, Switch off and receccnnect R3.
10, Switch on agein and rcducc the input level t¢ give a reading of aporez-
inately 200 ul in the 1st LM neter, Carcfully adjust the slugs of L6,
L5, L3, L2 end L1 (in that crder) for raxirun rcading,
KR KRN KK
VHF & TV GI(UP WIA MSW TIVISTHM
The Centest Cormittee of the NMow Scuth Wales VHF & TV Greoup invites
Naticnal participation in a VHF - UHF Gentest te be held in August anc there-
aftcr annually, This centest is very similar to that spenscored by Lavid Tanner
VK84iU, in July of last ycar., Like L&vid, the Corrittee fecls that ccntacts
via speradic E do net reflect the eperator's usc ¢f 'state of the art' cquipment
and 1s unfair tc these vwhe are cxperirenting with scatter corrunications and wesk
sisnal technicucs, For this rcascn, coentacts via transcguetcrial prepagaticn are
also discualified,
The rinirur distances sp.cificd arc based cn the norral range cf 'b ginner!?
type stations running low pewer to relatively srall antennas,
A Trcohy, to bhe knewn as '"THE JOHT MILLEXL VA2AVF T PHY' will be awardec to
the outright winner, ancd ccrtificates will be awarded tc the highest scorer in
each Statc cr Territcry of the Corrrnweel th,
It sheuld be neoted that erly indivicdual /rmateur staticns are cligible te
cnter, Club or Scecicty spenscered staticns (e¢,gz, Illawarra Mecnbcunce Preject)
are net eligitle for the Trephy or Certificates but may, of course, previcde the
'cther end! cf a scoring centact for an cligible staticen,
RULES
1, LURATICN 000 Hrs, 4th August, 1972 tc 2400 Hrs, 20th Ausust 1972, (211 tires
E.A.S.T,) Note that the Perscids Metcor show will cceur durinz this pericd,
2. Thcre is cne Tivisicn - Transmitting, (oen,
3, A1l incdividual Anatcur Staticns ney enter, whether fixed, portable or robile.
L, M1 VHF and UHF bands ray be uscd, hut cross-band ccntacts are prchibited,
Cross-rodc cecntacts are permitted,
5, (nly cne ecntact per band ner statien is allewed for each calendar E, A.S.T. cay.
6, Intrants rust cperate within the terrs of their licences,
7. Before peints may be claimed for a contact, scrial numbers rust be exchangecd,
The serial nurbcrs of five or six figurcs will be ermpesed of RS (telephony) or
RST (telesraphy) rencrt plus three figurcs, cerrkncing at 001 fer the first contact
and increcasing by cnc fer cach sSuccessive cecntact,
8, (n the 52 MHz band, contacts via thc redes generally referred te as Speracdic E
and Transcquatcrial prepagation will be disallcwed, The Corrdittee reserves the
right to adjudicatc decubtful cases,
Contacts cver distances belew 50 rdles on the bands 52 to 450 VHz will be dis-
allowcd as will ccntacts bclew 25 rmiles on bands 576 1MHz and abeve,
Ccntacts on net frequencice cr through repeaters will be disallowed,
9. Scoring for all ccntacts will be bascd on milcazc rultinlicd by a factor
dependent on the band being uscd, as fellows:
JMAND F/:CICR cr MULTIPLIER
52 MHgz o (6 05 6Bl W e e @) o W8 6 b e 6 6 0 8 1
144 " oo w0 150 e b8 e 8 3 ) 5 S e 85 B3 2
432 ¢ 3
1217 5o ek S B B 16 e B8 8 6 o Buet 5 6
abeve 1300 MHZ vieirerevecencnacane 8
(ecntinu )
L
o
Bach lcg entry rust shew the claimed milecaze end scere, In the cvent of twe
stations disagrccing cn milease, the average cf the twe cstinmates will be taken,
10. A1l logs rust contain the fellowing information: Pate and Tire (E.A.S.T.)
Dard Emission, Powcr, Ccll sim worked, Scriel Mo, sent, Seriel Ne, received
Tistance, Peints clain,
11, Entrics and legs sheuld be forwarded te rcach the Cntest Cormittec on or
before Friday, Scpterber 15th, 1972,
Send entrics te: The Chairnang
VHF & TV Group Gntest Cormittec,
14 Atchison St.,
CRCWS NEST, 2065
ISR R RS S S
(PERATICN AL, AMPLIFIER
The cperaticnal arplifier is an integrated circuit package crnsisting of a
rultietransister goneral purpese analoguc armlificr cn a singlc chip of seri-
ccncductor material,
These doeviees are characterized by a very kich input imedance (ty»ically
2M CHm) very high cpen leop veltase gain (typically 200,000) and low cutput
rcsistance (ty~ically less that 100 (1) The freouency resacnse of individual
amlificr confipurations vary, but all have flat gain-frequency characteristics
fren 1,0 to scveral hundred kilchertaz.
T'.C, veltase gain is achicved by the cxcdusive use of dircet ccupling within
the arplificr, Special op, arps arc availeble which will agglify in T, F., cone
figurctions up tc abcut 200 VHz 'ut single deviees such as FE,T.'s are lcss
ncisy,
Duc to extrerely high cpen leep veltae cains, these arplificrs rust be
uscd with hecavy ncgative feod hack tc awid cutput saturation and lateh up
(isc, cutput veltage swings up te the suply petential and stays therg. When
ncgative fcod back is erploycd, very stoble gains of up te 6040 result, depending
cn external circuitry.
SCHEMATIC TTAGRAM CF (PL ATI(NAL AMPLIFIER
+V supply
Norl InVekning\/
INPur
Va
OUT PUT
V2
I MVERT 1Y ¢ O
INPyr
& =\ supply
/q [H/Lg'c" K/ofi
PAGE 6
The arplificr senscs (V1 - V2)
(utput
Vo = A (V1 = V2).
The iceal cp-arp.Thoecretically has en infinite input irpedence(Zin), infinitcly
large weltase gain (4) and zere cutput resistance (Re)., The circuitry within
the "lack bex" is wmirpertant tc the uscr,
TYPICALL CP-AMP CIRCUITS:
CNST/NTGATN TNVERTING MPLIFIEL:
Vour
RI- R2 , 9
—T = VourT _ —
RI+R2 Voo © RT oessa toor
The R2 connection constitutes a negative feedback configuration.
For UA74IC ch-arp
Gain R1 n2 DWW R IV
1 10k 10l MHz 10k
10 1k 10k 100XHz 1k
100 1k 100k 10XHz 1k
1000 100 Ohm 100k 1Kz 100, Ohm
NCN—INVERTING A PLIFIER:
- High input impedance
- Gain
Cain =1+2&
+R1
For UA74IC ch-arp
Gain 1 2 Ze Y R IN
10 1k Ok 100XHz 400M CHr
100 100 CHr C.% 107 Hz 200M CHn
1000 100 CHr: 99,0k 13XHz S0M CHn
DULIETIN CF NCRTHERN Z(NES W, I. A, TAS, AUGUST, 1972
PAGE 7
1KHz sinc Wve Cscillater
008 MT
2k
2
j%} /o k
Adjust 15k for wndistorcd sinc wave cutput (which cccurs at a gain of 3 cxactly)
A major apnlication of copearps is in analoguc ccrputers, where very accuratc, stal
veltage gains give risc tc accurate calculation and sirmlaticn of mathematical
redels of physical systens,
Cther applications for op-arps include clippers, intcgraters, adders,
differentiateors, low drift arplifiers, notech filters, digital to analcgue ecnverta
schridt triggers cte,
The only pessible disacCventages with such devices is that a positive and a
ncgative pewer supply is rcquired and the arplificr itsclf will saturate if
cver driven,
Mcst redern op-arps arc fairly reclust, but never reverse supply pelarity,
sincc this destrcys the devicc,
/{/fl74// C Pin ConnéEeTions
TAB
OFFSET Iuy( \[+ (,8 Vol7s l"lr\)‘)
o
IMVERTING
ourpur
Nont [NVERTIN ¢
IMPuT
V= (18 VolTs mnx)
( REFEREN CE: FAIRCHILI LINEAR I.C, TATA)
WALLY, VK7ZWX,
FRRRK
NFFERRKRIS
C(NGRATS tc GERRY 7ZCGP cn the birth of his first harreniec,
PR R w KT R KR
SELIEVE Jce's days cf frecden arc fast drawing te a closeilil
FehdhFRARE
KK