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BULLETIN TSSULD BY THE NORTHERN ' ?,0,BCX 1010
ZCNES CF THE WIRELESS INSTITUTE LAUNCESTON
CF AUSTRALIA TAS., DIVISION TAS, 7250
JULY
VOL, 3 NC. 4
e ee S o ete e 4.e oe i
REGISTERED AT G, >.0, HCBART
fer transmissien by nost as
a hericdical, CATEGCRY B, PRICE 10¢
REMEMBRAN G DAY CONTEST
The R.D. contest will be held on August 18th and 19th. I am sure you all
new just how much your prisence is reguircd and that this year, cur Gelden
Jubilee year weuld be really complete if we had the Troohy in cur midst, We will
stand more than a gocd chence ¢f winningS if we all narticinate again as 299 did
last year, However, this time we necd an increase in peints scored; any sco€ is
a zreat help but if you have the time let's try and exceed 300 noints. |
A rciinder tc our asscciates that weuld like a callsign of their own that the
next exam is in Auzust. Your apnlication should earrive at Radic Branch befcre
the 8th July. Fer those that necd therm, I have a fow apnlicatirn forms,
JCHN VK7JV,
HBFR KN R IRH
DATES _TO_WATCH
3rd JULY NORTH WESTER! BRANCH MLETING, LAKIN'S HALL, ULVERSTCNE
13th JULY NORTHERN BRANCH M ETING A, E.B, RCOMS, HIGH STREET
20th JULY IREE ANUAL T"IJLETING, GAS CCMPANY THEATRETTE, ST, JOHN ST,
(7445 open tc merbers only) WISITORS WELCOME AFTER ©,30 pn
at which time Technical films will be shcwn,
7th JULY GOLDEN JUBILEE DINNER, LAETARE GARDENS, HOPINS ST, MCCNAH
7th & &th JULY 7L MIMORTAL CONTEST FROM 800 to 1200 GMT ON €0 METRES (LY
THIS CONTLST IS OPEN TO VK STATIONS, THE USUAL RST A'D
NUMBER LOGS TO ZL2GX
3o SRR RN HFH
BULLETIN OF NORTHEI ZCELS W, I, A.: TAS, JULY, 1973
The Menthly Branch Mceting of the M-th;m Zene held on Junc the :
was attended by 50 members which is an all time rceerd feor an cordinary reeting,
The epening of the meeting was rather a scrbre affair when cur chairmen 7PF
Peter called fer a 2 minute silence in rewory of cur late patren Mr, Len Crccks
730, cr just plain Len as hc was affecticnaltly known, Fellcowing this tribute to
Lcn the Treasurers repert was presented and Kevin 7ZAH stated that the Branch
had a credit belance of seme $812,00 - Szles te date that is frem the time of his
last redort te .tedays date tetalled just cver $527,00.
John 7JV renorted that the club rccm account was just cver 760,00,
Feter 7PF zave latest rencrt on Oscar activitics and played a tape recordin of
scre recent contacts by the satellite, Mention waes alsc made of Gl 7LZ's
citerial in €. R.1i., in which he call.d fer tere activity threugh the satellite
enc judping frem the comments I have heard sere rembers are nating an cffert teo
~ct Lcflll’)n(nt tunua te Orcar f‘ruou(,ncy
Yeur scribc hopcs te have 30 watts of CW en the ge within the ncxt
fertmight,
Twe new apnlicaticns were reecived fer student rerbirship of the Institute,
these were arzreved by rmembers present and pnassced te council fer acticn - we extend
a welecrie to Richard Tanner and Mark. Corbould, and lock ferward
teo the day when
thcy becere full renrmbers,
The. jubilce Dinncr as has becen advertiscd cver the last ccunle of renths
will be held on July 7th. . Tickcts arc available frem Reg. 7KK but rore imertant
is the peint that you sheuld lct Reg, cr I know, NOW IF YOU ARE GOINGi This is
rest irpertent so that the catcring arrangerents can be finalised, Tickets %5.00
a dcublc $10,00, The dinncr will be prececeded by a General Mecting of the Tos
Divisicn of the Imstitute, The agenda will be drawn up by Council. and merbers arc
aslkcd to discuss the iterms con it befere »lunging inte "General Busin.ss" just in
casc timc runs cut,
Scre discussicn was held in regards te the R.D. ¢ rtest and as this is
cur Jubilec Ycar it was thought that we sheuld rske a cencerted offcrt to get the
Trenhy back, If we can get at lecast six cperators te work thrcugh the 24 hours this
would »ut us well in the running, Additicnally te these 24 heur staticns it weuld
be a preciated if cverybedy cculd rioke en offert and subrdit a log in excess cf “00
pcints cach., Lct's hepe that again this year we can ect the same supnert as we ot
last ycar frem the VHF cpcraters and I' surce the HF wrkers will cnsurc regular
cntacts with them, Perhaps a high 1light ¢f the evenin @ was the aucticn sale so
ebly handled by Jehn 7JV, TFor these who did net attend, the salc crnsisted of a
salc of Bits & Picces, I think that is the cnly way to cdescribe the iters denated,
These were scld off te t csc whe attended the meeting with a surplus of DBs. and
1thrugh the final figurc is net known tc me I belicve the arcount was scmewhere in
the vieinity of 5,00 sc this finc ¢ffort should ta:e us well on our way towarcs
cur first $1,000,00 in the club rcen acerunt,
I gucss the presecdin; pararraphs arca fair rc port en the night's
activities, and trust thet we will sce you a1l at the nuxt Brereh noeting,
vhich will be held as usual, cn the 2nd Fricay of July
73s,
WORMAN, MR,
MAX TMX menticned in a letter tc ne the cther day hc is now back on single band
aftcr curing a fault in the balanced roduleter sceticn of his rig., He is also
well advanced in the instalaticn of his mini becan se we can Cxnecet any day now
o 20 retre simal in Lewccesten as streng as his &0 retre signal,
330303
KRFhn 3 3W 33 sl
WhwH
Q. R, I, JULY, 1073
BULLETIN OF NORTHERN ZONES W,I.i. TAS. PAGE 3
NCRTH WESTERY BRANCH NOTES
Al theugh this may not be the ideal nlacc te talk abcut C.°'. it has ben
in cur local discussicns latcly, If vere theught end reascning is not anplicd
te this arca cf Ham activitiecs the day will ccme when the prepencerance cf
Aratcurs will be VHF CRYSTAL LOCKED BUTTCN PUSHERS, St~ werds you say, but
think abcut it! Very little cffert is rcouircd te ta ¢ cut the full call and
it is in thc main on h,f, wherc a lot of renitoring tacs nlace and Ham activity
is asscssud, V,H,F, w:1]l nct last long if cur h,f, bands arc lest threugh lack
~f activity., Sheet ro down in flarces if yeu 1ilte but the truth is hard to evadc,
Give 1t scme scricus theucht, you will find »lenty of co—operaticn available,
Trsraria for a vacation in carly Jvly and sheulcd be hcard en 2, He w711 s oo
some time in Hebart and some cn M.W,Ccast, Ho is leckihg forward tc some
fustraliann Rules™ which his harronics have ncver scen, What luchk|
Dcubtless by the time you sce this, Los 7LH will be nacking e fat SSB
simeal of h.f, My roovisticn is on the way cut, O~ VHF it a-ocars that a great
deal of censtruction, rocdification, antenna work cte, is going c¢n in cur area.
Reports arce recucsted nightly and therc will be rorce chennel switching shortly.
Teny 76X and Iar 77IE arc heord 5 reterwise freguently, I understand Graham 770
has feund cut how te phase medulate witheut cven trying,
There is also considerable activity ercund the few h,f, beys in Devennort,
ntennas, ccupling units, and asscciated cquiosment arc in the news, Wo st give
Burnie a shot in the arm,
The VK7 Jubilcce Avard is ccrteinly crcating scre interest, Many contacts
have been nmade fren this erca, A littlce difficult fer V.H.F, %3,
Nevw fer the story cof the renthi David 7MS exnlainced that he had suffercd
a Kakattac't the other cday, per 2, He said thet it was scmething like a hcart
attack but rore psychclogical, He had just clirbed a 70 feet gun pele per
stcel spikes and freed a halyerd, A1 systems are ncw normal. Moch like a snhacc
wall but therc is only cnec way tc falll
C,U:L,
g
Ive
B35 R NRAG ¥
FOR SALE
I..55 FET VOLTOHVETER, USUAL RANGES, SIZE 5x3:x2 INCHES WITH LEADS A'D
C/RRYING CASE, CCNDITION NEW, FULL DESCRIPTICN ELECTRONIGS AUST, DEC, '72,
TAGE 129, b6 aaises . A BARGATN,.,.....%30,00
VX7JC, 2 LURCRE PLACE, LAUICESTCH,
“ue ke Lie
DULLETIN OF "ORIHER' WoI. 4, TAS, JULY, 1073
PAGE 4.
PROPOSLD FM BA'D PLAS
In passing on 1y cninicn, in an atterpt te help seclve the B bend plen
centreversy, I have been able te dray en vy _xoericnce with beth BT and satellite
rencaters, I have tracked a1l Qgcars and - ienals threugh Oscar 3, 4, and
sc far hove 0SC'd 5¢ stetions via “Oo I was privarily resoensiblc -for the
establishment of VE7's cnly repeater, VI7RiAA on Mr, Barrow, which has been
licensed for 20 rcnths,
Now we must lcck intr the nced te aprce on frecuencies te be used fer
terrestrial and satcllite repcaters, The basic reasen is that opcrating thrruzgh
rencaters precludes the frequeney of tronswmissicn being renitered., The Post
Cffice recquircs that the innut frecouency te torres trial rcocaters be not used
by oxisting ncts for this rcasen. Mo such c:vntr(l has becen exereiscd for
satellite cncraters and what we arc trying tc de is tc oHrevent OR:L betweern the
twe greups by velun tery contrel within the Amatcurmmy. Even with simplox
';')’\,I'Eltlcn the incorpeatibility of M with themodes used with Hresent satcllite
N
Fes QR contrel difficult,
A1 nortics anparintly have agrecd te reove CHA outnut frem 145.9 rhz
ard leave at lcast 145.»3 te 146 00 whz clcar fer satellite use while scre
guarters wevld like it clear down te 145.8 rhz, Onocnents te this wider »nlan
crntinuelly cucte Region 1 band nlans, th rc xng channels on 147,900 and 145.95
thz, This is thc cencern of thesc In Region 1, but cven se the reccivended ER
Pewcr of 15 watts and a deviation of 3 khz would not cause as much trouble as the
sower and devietion uscd here,
Let us new leck at the varicus types of QR which con occur.
1. B! staticons cen get inte satcllite repectors, 2. Stations usins the satcllites
cen OTM M staticns., 3., B staticns eon (R the wea satcllite cw t_»ut signals,
With the first casc ruch has beon said abeut torrestrial rorcaters sctting inte
satcllite vrepeaters but frem my cxpericnce it is the simplex stations which have
te be kept cut of the way., I have hoard feur Gil4 rencatcers via 406 the enly cnc
te cause CRM to the bcaern en 22,45 rhg is V<5\J1/R1. The translated frecucncy
of 145.Chz is 22,444 vhe, Vk5‘w_u’I/R1 2 nears te be high in frcqu:;ncy by abcut
Likhz, By far the strengest spuricus sirnmels & bo hprd arce fremCh B stoticns,
os rany as five sprcad cut over abcut 6khz, ond freo their strongt‘qs weula
rmning high ncwer and beans, The sceend forr M oquite e s«)l* hasn't been
netlcu’ in Vk2 as the number ¢ £ staticns using small crimared with cther
' M SSB statien car pley havee with crs nearby, The third fers
£ O will net ccecur till 407 but a lcecol I wuld wine any weao satellite
sigrel. It stands i rcascn that beth simnlex mf“rencater staticrns rust be
clearcd te prevent rutual O with satellite cncrators,
Vew tr the varicus bend nlens, all of these in VI and cverscas arc based
cn vepeater In and cut frcqu.:ncir,s bcing spaced arcund simmlex channcls, The
Mbury »len meintained CH © (146.) 7hz) at cne cdge but ree rmended cventual
change te five simmlex channcls b tween 146,45 cnd 146,65 ~hz, A stated ebjecticn
by V72 of the Albury plan is the recuired width of eccoptable receiver nerforiance,
147.0 down te 145.35 vhz (CH 4). UFow this is a technieal peint which denends on
the type of cquinnint uscd bpto sinister cenclusicon ariscs bocausce of it
The VK2 nlen puts th. satellitc sezment in the rdddle of the allceated frecuencics,
thot nertien usually uscd fer simmlox usc, VWhat con come fre= this., CH 4 (145.75)
will be erntiruved te be usced, it hes alrcady bocn said te me that the cperators
cn the nresent CH 4 In VE2 w uld tac odvent: of cxisting 145,9 mhz RX cryvstals
nd cstablish a new simlex chenncl, It weuld ta ¢ wory ruch feresight tc scce
145,95vhz weuld fellow and we weul? have sivnlox channels right ncross the
gr uC.H_l'tC bend, The enly cther freguencics e npw sirplix chanrnols weuld be
belew 145.5 or abeve 146.4 thz, cither way would bring up the sc called preblen
£ acecntance bandwicth of cquinnent, I o ],n;mfc r¢ of the oninion thot the enly
lene term scluticn is tc adept the Albury nlon which cleors the frecucncics bolew
146 thz for satcllite use, otherwise 11 the tire end effort cver the past year
will heve been te ne ava11
P.D.FRITH, VX7PF, VHF CFFICER, 0SC/ CCOORDINATCR
COUN CILLOT V7 DIVIoIO‘\‘‘nl.’;,
Q. R. 1
DULLETIN OF NCRTHERN ZQNES W,I,A, TAS., JULY, 1973
PAGE 5,
I WAS INFORVED by a ZLstaticn the cther cday that therce is a VH award bascd cn
the number of Elccterates werked, DBasically you need 25 confirmaticons censisting
~f 9 OSL's frer VK2, 6 fren VK3, 4 frenVX4, 2 fren VK5 and 1 cach frer VK1, 6, 7
and 8, A tetal of 125 Elccterates are available, all contacts sincc 1st. Januurv
1073 arc velid. Apolicaticons tc ge to VK3APU,
36363 363 3% % K3
BASIL VE6EB and XYL will be arriving in Sydney on 4th July. He hepes te arrive
in Tosrania arcund the 11th July where he'll stey with his brether in Dovenpert,
fer a fow days before going te Lawmcesten ané Hebart, Basil will be robile con
2 ncters CH4 end B,
IA
HFR K
HEATD THAT the bottle drive sheuld raisc arcund $35.00 cur thanks te JOE 7ZGJ,
GRAEE 772GG anc STEVE 7ZSF for supnlying the rmscle end the trensport and thanks
te cur members for the sundly of bmtns! If they risscd yeurs give JOE a ring -
it's not tec latel
FRERT R
UCT TCC MANY 2 metre Al or SSD transmitters ar und if Wednesday nights are any
indicaticng 8 far the only cncs beard arc JOL 7ZGJ, KEVIN 7ZAH and JCHN 7JV, Hew
abcut YOU next Wednesday night - say 8,00 o
F K IR NN
WL ARE PLEASED to anncunce that since the thrcat of disbandrent of the VHF greun in
Tebart attondances have incrcascd to the peint where at the last mocting 12
members were present, ,
FERG R AN
7R has get himsclf en auteratic reniter cvery time he fircs up en 70 metris cne
~f the spcakcr bexes of the hizh-fi systen in the leunge recem talks back to
him, This spcaker box will even talk back when it is cerpletely discennceted
frcm the rest of the cquiprient, Tn cthir werds with the bex just steanding therc
it will dctect end rectify his 20 retre transmissicn end believe me, its net highe
fit The sarc character canc up cn "0 metres last Soturday ewvenin - and was
immedictely swarped by ZLs locking fer Gelden Jubilee awards, He was gble tc
wrk ten cf these gentleren, Sc orermcriber the award and de get en air if you
can cver the remaining few ronths,
A FHR KRN
REG, 7KK has ncw get his tower creeted in the garden, and Wal, 7ZWX spent a gocd
ten rinutes at the tep, We are not sure yet whether he was locking at the ‘
ronge te be expeeted at the tep of this mast, (that is line of sizht range
fcr VHF usc) cr whother there was scmcthing intercsting twe cr threo g*qrc‘cns
dewn the streetl
RR R
DRIAN 7ZBY hcarc tc remar: the other rerning that he may not be available
beecovse hig XYL was appearing in Oscer; cr perhons he has newver ret Cliver,
which naturelly »uts a wry twist -n thu story, docsn't it}
) FH5 ARRN KR
HEARD ASCUT the charactecr cn 52,525 Tl whr, takes a brecat tc allew lcocal bacb box
vicwecrs te watech the ccrrmcercials!
B} 7
BULLETIN OF Tflfl‘fiORTHERfl Z01ES LA TAS July 73
page ©
ILCIICAL JATICLE - VIETZBY
4250 ILls FREQUUNCY COUNTER PART 3
Count Gate andSubtracting Decades
4s the operation of the countgate end subtracting decades can at
times affect each other, they 711l be described together. To fully
understand this section, onc must know howr o "IUD" gate works as this
is the type of gate used in this circuit. Mig. 5 shos the symbol and
truth table for a 3 input “IAID" gate.
e
::..
= O O - Ot
= O = OO [ey]
Logic 0¥
Qb
<
o
i
o
Togic "1" = 2 to
It will be seen straight away that if any input is at Logic "Ov
the "Q" output will be at Logic "1"., The circle on the output indicates
that an inversion takes place as proved in the truth table, The circuit
of the count gate and subtracting decades appcar in Pg. 6.
It can be geen from Mg, 6 that the count gate is actually 1/3 of
a 74010, which is a high-opced triple threc input "NAQID" gatc. The
ceetion which performs the operation of count gate ig sccetion "BY,
Scetion "A" controls the signal to the subtracting decades and section
non allovs for normal opcration of the counter or for subtracting 455
1077 from the incoming signal. The 230D (binary coded decimal) outputs
of the three decade counters (7490) arc fed to a dual 3 input "yAD"
gote 7430 of which only onc scetion is used. The way in which thege
MIAITDY gateg and deccade counters work is as follows ¢
Assume gwiteh "S1" in position 1 (mormal counter opcration) and a
Logic "1" availablc from the count gate control circuit. With switch
S1 in position 1 a Logic "O" will be applied to gates 2 and 3 of scction
C. 4 logic 1" from thc gatc control circuit iz also applicd to gate 3
of scction 4, and to gatec 2 of Scction B. Becausce we have not yet
applicd a signal to the counter the outputs from the three decade counters
will be at Logic "O" and therofore the Q output from the 8 input " XD"
sote will be at Logic A, This Logic "1" ig applicd to gate 2 of scction
no and gate 1 of scetion €. If we now apply a cignal to the counter it
ig first shaped by the input boaord and passed on to the count gate ag a
series of positive going pulscs, changing from Logic "O0" to Togic "1M
and back to Logic "O", and ig apnplicd to gate 1 of 3cetion A and gate 3
of scetion B. Lg the signal pulsc riges to Legic "1' the output of the
count gate goes to Logic "OW and back to Logic "1" vhen the gignal pulsc
falls to Togic "O". The outhut pulsce trein of the count gate will be
thercfore, an cxact duplication of the input but inverted, and will be
passcd on to the main counting decades. Thig sane shaped input signael
will also be applicd to gate 1 of scetion 4 and again causc an inverted
pulse troain to appcar at the Q output, wvhich will in furn be counted by
the subtracting dccades, but these decodes and the 8 input MIuD" gote
pley no pert in nornel counter operation ot this stage. Becausc gates
2 and 3 of Scetion € arc held at Logic "O" by cwitch S1 itc § ountout
will be at Logic 1 at all timcg and have ne effect on the count gate.
Q. R. Il
BULLETTIN OF THE NORTHORN ZOUES WIA TLS July 73
TECHNIC.L JRTICLE (Contd.)
The train of pulsce to the moin counting decades will continuc to pass
via thce count gate, until the Logic‘i"from he count gatec ecmtrol goces
to Logic "0", Thig will causc the Q output of the count gate to go high
and gtay high until the next Logic "1" level fron the count gate control
circuit. i -
Wow consider that we wisgh to usc the counter to rcad the frequency
to which a recciver is tuncd, This is acconplished by opcerating switch
S1 to position 2 (Logic "1"), The operation of the count gate is now
under the control of scction C because gatcs 2 and '3 arc now high, and
1 from Q output 7430) and therefore its
1 is also high (Logic
zate
output will be at Logic "O" ond no natter what the logic level of either
the gate control circuit or signal the count gate cannot open until
cgate 1 of se¢tion C gees to Logic "o", The way in vhich this logic
level changes to gate 1 of secction C is acconplished is as followss
Gate 2 of section 4 is held high by the Q output of the 7430, gate
3 is held high by the logic "1" level from the gate control circuit
and gate 1 is going from Logic "O" to Losic "1™ and back to Logic "OY
in synpathy with the chaped input signal. This train of pulses appear
at the @ output of scction L and is counted by the three decade counters,
This .continues until the Q outputs of the three decade counters reach a
count of 455 (455 KiZ). This occurs as follos: The last counter
reaches a count of 4, the seccond counter rcaches a count of 5, and the
first counter o count of 5. .4t this point all inputs of the 8 input
"D gate go high (gates 6, 7 and 8 connccted to +5 volt rail), With
all ‘gates at Logic "1", the Q output of the 7430 gocs to Logic "Ov.
This Logic "O" is cpplicd to gate 2 of scetion A causing the Q.output of
thig scction
to go to Logic "1" and to be held there and therefore stop
the pulse train to the three decade counters. This Logic "O" from the
@ output of the 7430 ic also applicd to gate 1 of scetion G, which as
¢xplained before wvas required for the count gate to open. In this nanner
the input signal has had 455 KHZ subtracted fron it before the count sate
opened., P
For example, a receiver tuncd to 7 M4, VIO tuncd to high sideof
signal (7.455 MUZ), IF frcquéncy of 455 KH%, the counter will subtract
455 KHZ fron the VFO frequency lcaving 7 1MIZ displayed vhich is what
hie receiver is tuned to. The circuit will work on any IF frequency
(up to 999 ¥HZ) by sclecting the decade counter outputs teo feed the 8
input "NAND" gate. The count gate will rencin open until, as before,
the Logic "1" level fron the count gate control circuit goes to Logic "OM,
Licreby closing the gate. The subtracting decade counters are reset (all
Q outputs to Logic *O" by the normal counter reset circuitry. This
preparcs all T4H10 scceticns aud the 7430 for the next gote control pulse
vhich w7ill allow the vhole procedurce to be repeated., It can also be secen
hat the readout is to 1 KdZ, duc teo only three deccade counters being
used, therefore the gate centrol pulsc width nust be 1 1/S (1 KZ). 4
gating indication is also provided on the front pancl by nmeans of an LED
(Iicht Bnitting Diode) which ig driven by transistor TR1 (BCL08),. whose
base is connccted to the counter resct line. The LED vill glow vhen the
reset line ig at Logic 1. i
LRRATA JUNE - page 7
The pulse shaper IC (F9582) on the input board was incorrcctly
deseribed. Instead of being called o highespeed BCL dual D flip-flop,
it should have beon described as a nulti-function line receiver Jemplificr.
ol By
o g v
7hiHio 7L30
ey v
" 4
of @oyos L7 P wisscTive me @
July 73
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