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DBULLETIN ISSULD BY THE NCRTHERY Z(MES CF THE P.C.3CX 1010
WIRELESS INSTITUTE CF AUSTRALIA TASMANTAY DIVISICN LAUN CESTCN
Ny
TAS, 7250
JUNE
VCL, 2 NC, 3
-
REGISTERED AT G,P.C, HCDART
for trensmissicn by ncst as
a Pericdical, CATEGCRY 5, PRICE 5¢
I believe that the talt ancd slide show by MR, BCD WCCLHCUSE
was a great success anc members indicated that they appreciate
sonething nrn.clectrenic oence in a while, This shculd be kept in
rnind when lockin: for suitable subjects, in the meantime if you have
an intercsting jc-b, hobby or spert that ycu would 1lie to tell us
about why net tell REG 7XK our hcncrable secretary.
Lectures premised te date arc:-‘ ‘.
The T.V, Staticn cn Mt. Barrow by Dill Carter 74K
The Alurninium Industry by Chris, Yalker 7UX
Skindiving and Uncderwater Photography (with slides) by Mr. Ken
Atherton _ .
HHHHHHH
K
MEETINGS
JWNE 6 th NCRTH WEST ZCNE AT LATIN'S HALL, ULVERSTNE °
JUNE 9 th NCRTHERN Z(NE A.E,D. RC(MS, 51 YCRK STREET
RARRNH KK
Y, R, C, S,
Classcs
JWE 3rd - 17th - 10,00an (M 38 KINGS MEADCWS HIGH SCHCCL
JULY 1st 10,00an ROCY 38 " " "
SULLLIIN UF BURINDAE ATNDD W, 1.8, 180,
NCRTHERN MEETING
" This was held cnce again at the High Street A E.B. rocms and
there were three major issues discussed:-
(1) 2ill VK7AK reported cn arranscrents for the Federal Conventicn
at Easter .1973. ‘After some difficulty beckings were made at the
Kings Mcadcws Hotel for accomedation and at the Launcesten Hetel
for the Conventien facilities,
(2) Serc corments were fortheeming on the preposed Tasmanian
Jubilee award to be available during the Tasmanien W,I.A,'s 50th
Inmiversary ycar 1973, Yoest discussion centred cn the number of
staticns to be worked .to qualify for the award. Nc¢ doubt details
of this award will be published in the Tesmanian W,I.A, Dulletin
in cue ccurse,
(3) After ruch debating if was decided to open a Nerthern Zone
Clubrcons Acccunt, Prcblems invelved in helding reney in such
an accocunt werc highlighted,
The business scssion was followed by an interesting talk and
slidc show on Cavancering by Mr, D(3 WCLHCUSE, The scricus attitude
and safety angle of this sport was very cevident, although funny situ-
ations cen arise for instance when you recet a snake at the botten of
a 300ft, shaft and the cnly way out is UP1
FRFHAKINK
A,C,C, satellite is now expected to fly in Nevenber,
KRFHFRHK
BCB VKMT having accepted a jeb back in England left Tasmania on
May 17th., Dob hopes te be able to get his cld call G3YN back so
if you hecar hin give him a2 call,
RN RKIN LXK
CCL VKOJV is ncw back at Casey basc after being cut cn a ficld trip
fer sere 9 wecks, They werc slowed by blizzards tc 4 miles in 5 days
on the way back, Gel is quite active cn 14,120 Mhz and locking fer
VK contacts,
PAGE 3
N,W, ZCNE NCTES
The rost interesting news of the renth is the aquisition of
twe new- operators tc our area, Graham Rand 7ZA0 and Ian Ellings 7ZIE
were successful at the last exam, Ian was fortunate to be cperative
on 2 rmetres in time for the big opening and becanc known interstate
overnight, Although hecld up temporarily for crystels, Grahan successe
fully redified a low band wnit and is now making his presence felt
in the area., It locks as though Ian has beccome the local watchdog
and visiters will find it difficult te eall and receive no reply.
GOCD SHCW IAN]
Cur reeting went off wvery well, attendance being a little better.
I have had twe reperts fron absenteces whese cars were cut of order on
nceting nicht, In future plecasc call the Secretary and he will arrange
transport for ycu,
The meeting for Senterber has been set aside tentatively fer a
ladies night.....80 chaps warn your XYL, YL or bcth to have their
hair frizzed up in readiness fer a tig night. .
Recently was hencured to entertain SYD znd XYL ANN VK2ZYD who
were on their hencyrcen in VK7, Syd was mobile cn a picee of JA
ecuiprent with cbeut 5 channels cn 27, and 20 watts cut, It is un-
fertunate that they failed to make any contact in the South, It is
larentable that you ~issed such a delightful ccuplel
7KH has been hors de ecmbat on his H.F, rig, It is possible
that you transmitted toc far Ken and straincd the works, Hepe repairs
are quick,
Scrry tc hear that cur cld friend 730 has been grecunded in
hospital, We all wish you a specdy recovery Len,
During VHF cpenings we had the opportunity of a yarn with
Peter, was 7ZPW now 37ZPX, Fron breakin rermarks it is obvicus that
Peter has done nothing tc cdamage his local reputatien,
Phil 3APC is filling "Sparks" job on the BURWAH , calling at
Devonport cnece a week, Mways welcone abocard if you can find the tire,
73 Until next ronth,
X,
e e e
DULLETIN CF NCRTHER Z(FES W.I.A. TAS, JE,
PAGE
4
HAVE A LCOK INTC THE PUTURE
i\.vcvcsescsne
.
In 10 or 20 yecars' tine will thce Nerthern Zone of the V.ILA, still §
cnly offer:- -
(a) a renthly nowsheet
(b) a mnthlj social "get torcther" at a nlace unknown,
Cit will ilt have rere to cffer, say
(a) a definite reeting place
(b) facilitices fer classes for beginncrs and r‘ox"e lcarmecrs
(c) a station installaticn and workshop for these lacking sare
() a reecea for local and visiting clectrcnics cnthusiasts
(e) a venue for extra social activities
SURELY
We want to achieve sorething by this tire,
Cther similar groups can obtain clubreems, Why should we be toc
scareC to try.
Cur rembership at the rement is at onc of the pericdic high spots.
Instead of waiting for it to decreasc, utilize the enthusiasn of our
present menmbership,
The first step is $1 - 2K for a block of lend - then stand back
and cdeeide whether we can prececed te the next step,
A nuiber of individual members have shown that they can casily
carmn, in the Institute's name $200,00 in cnc rrnth, The geoal mentioned
abcve then is nct impossible te rcach in 1 year withecut diszing into
cur own peckets, As one nember put it, "when you cwn land, the bank
nanager srilcs on yeu',
2C
Let's kneck the knockers end got on with the task by curing in
ideas te reisc roncy end by essisting cfferts suggested, v
We've ncthing tc lose and plenty tc gain,
» KRNI K
THE FIDRE GLASS BDLAVKS HAVE ARRIVED SC IF Y(U NEED (NE DETTER DE
JUICK - PRICE IS AP°RCXIMATELY $1,70 EACH,
IR
Q- Ro Mo
BULLETIN CF NCRTHEIN ZCNES W, I.A, TAS, JUNE, 1972
PAGE 5
(Cent, fren last renth) (CCPIED FRCM AMSAT NEWSLETTER)
Pararcter Unit Parareter Range Chan,No, Apprexirmate Calibraticn
o Dita/Corrents
Spare —— 20 20 ‘ Spare
Trans> nder ' ‘
R.F, Power W 0 to 10W 21 P(‘UT= 0,001 (N)2 (W)
Becacon R.F. A
Pcwer W 0 to W . 22 Peyp= 0.10 (N)2 (nw)
Iranépcnclcr ' |
AGC v 0 to 3V 23 Voo = 0403 ¥ (volts)
Micrange Cal, V . 0 te 1V 24 ~ N = 50 counts +1
N = Value telemetercd
“(orit rost sig-
nificant digit which
v identifies the data
linc nunber)
LIST CF CCMMAND FUNCTICNS FCR A.;Q-G
1, 2/10M Transponcer (N
2. 21/10M Transpcncer CFF :
3. 435 MHz Becacon Transritter (N
4be 435 MHz Beacon Trensritter COFF
5. Code Stere — Run Modc
6, Code Stcre - Load Moce
7. Morse Code Teleretry Enccder - High
Bit Rate (20 wpm)
8. Morse Code Telerctry Encoder ¥ low
it Rate (10 wom)
9. Transponder A.G,C, Locp Enabled
10. Transponder A,G.C, Loop Disabled
11, Corrand Codc—Store tc Mocdulatel35 MHz Deacon
12, Cormand Morse Code Telerctry Enccder to Modulate 435 MHz Beacon
13. Cormand Code~Store te Mocdulate Transhonder Beacon
14. Cormend Morse Code Tcleretry tec Mecdulate Transponcer Deacen
15, Disable Ccrmands 13 & 14/Enable Clock Sequénce (Switches Detween
Ccde--Store and Tclermetry cnce every 15 ninutes) :
16 Enable Corvend 13 or 14 (whichever was last ccrmanded)/ disable clock
sequence
17. Reset Clock
18, M/10M Trensponder CN (Redencant)
19, 2/10M Transpender CFF (Redundant)
20. 435 MHz Beacon Transrdtter CN (Redundant)
21. 435 MHz Beacon Transritter CFF (Reduncent)
Fe e eI
A 14/MHz opening on Sunday 21st May save us the best cpening to VK5 this
scason. KEVIN 724H, JCHY 73V end JCE 7ZGJ menaged to werk VKSZDY, VK5ZDX and
VK5ZK with goed simeals beth ways., (n the renecater scenc JCHN Qbrkéd
VK3ZKN via the VK5 repcater,
FeRRUHIHRK
( CCPIED FRCM AMSAT FEWSLETIER)
PRCPAGATICN PREDICTICN FCR AMSATCSCAR.C
by Raphacl Soifer, K2QGW
Prcpagaticn through AMSAT-Cscar-C (A-C-C) will be ruch like that
experienced with Australis-Cscar 5 (AC~5), thc principzsl differenece
facter being A-C-C's highcr nower cutput —-- abcut cne watt as copesed e
AC=5's 180 milliwats when first launched, Icncsnheric facters, nct
narticularly prencunced with AC-5 on line..of-sight pathsm sheuld be cwen
less cf a preblem with A-C-C, During AC-5's lifetine in orbit, srccthed
sunspet nurbers held steady at 106, very cleose tc the cycicel high of 111,
By ccrparison, W3ASK nrcdicts a srecthed sunsiet nunber of 43 for July
1972, ceclining tc 28 by July 1973.
The main opcraticnal difference, of course, is that AOC~C is a trans-
later, and has an uplink as well as a dewnlink, Recent ground tests
using the A-(=C receiver shcwed that a rcceived signal level of =130 dBW
will bc required tc drive the ten-neter transmitter tc full »Hower cutput
in a single-signal cendition, Assuming a slant range of 2000 statute
riles, an uplink frecquency of 145.9 MHz and a zero dB a¥crage gain re-
ceiving antenna; path less calculaticns give a required e.r,p. of about
€0 watts or 50 watts intc a dipole antenna in order teo attain full dewn-
link peower, This colculaticn assures an arbitrary loss facter cf 3 dB
for pclarigzaticn mismatch; during peaks of Faraday rctaticn fading,
signals wculd be 3 dB better, cduring nulls, scrxwhat werse, Uith 100
feet of RG-8/U and €0¢ transritter cfficicncy, anproximately 160 watts
input will be requircd with a dipcle antenna, Use of a four-clerent
bean at the transritting staticn weuld cut required power to abcut 7 watts
cutput at the antenna cor 23 watts input. Clearly the uplink will nct
nese a preblen,
Ls was the casc with the A'SAT aircraft flights, the downlink peses <
far rere sericus constraints, There arc scveral corpenents te the dewne -
link calculaticn —- frec space loss, receiver ncise, antenna ncise and
icnesnheric losses, Lot us take these in crder,
For the sarc ccncditicns shceificd abeve in the uplink calculation --
2000 miles slant range, dipele antennas, 3 dB pclarizaticon nismatch and
100 fect of RG.S/U, frec space less et 29,5 MHz werks cut tc aproximately
132 dB including »revisicn for antenna geins ancd line losscs, Fer a
rceeiver reeting usual armatour speeifications -- 0,5 uv, for 10 d3 SN
in a 2,1 kHz bandwidth, receiver-gencrated ncise is anpreximately 1.26 x
10~-16 watts, Tc this rust be added antenna ncise, For a quiet lccatien
at 20MHz, this will consist primarily cf galactic ncise with an agerage
valuc of 8,4 x 10-16 watts, The receiving noisc thresheld for a quiet
lecatien would be the sum of thesc or just abeut exactly -1504BW, The
ncise level cculd be perhaps 2 A3 lewer duc te variaticns in galactic
ncise, cr it cculd be as ruch as 20 dB higher fer an amateur in a necisy
urban locaticn, We will assurc a quiet leceaticn and an average ncise
level of =150 CUW,
With a srccthed sunspet nurber of 43 or less, icnespheric blockage
due tc F, refraction cught to be negligible, cxcept perhaps ncar ridday
at equatcrial latitudes, Fer rest amatcurs in the U,S,, Eurcpe and -
fustralia, F_, blockage, which was minimal with AC-5, shculd be just
abcut ncn-cxstent. Sirdlarly, nondeviative abscrntion at nocn for
40¢ latitude is predicted to be 2 dB cr less for clevation angles of
50 cr rere(distences te subsatellite peint of 2050 statute miles cr
less), TFer clevation anglecs of 20° cr rore, abscrpticn should be
negligitle, This is net to say, hcwever, that the icnespherc will nct
nake itsclf fclt, Tlcckage cduc to sporadic-E, when present, cculd take
the sienal cut entircly, Particularly cn paths traversing aurcral
letitudes, scintillaticn end flutter—type fading will be noticed in ruch
the sarc way as with AC-5, (T SE GONTINUED NEXT MCNTH).
Ever wanted tc run your robile rig off the pzmins cr convert it o a2
base staticn. Well one of the locals wanted thc latter anéd I =t the
job of building the nceessary supnly.
To supply the ncceessary notential two ex tclevisicn transforrmers
wcre used,
The onc marked A was uscd with a veltage-dcubler and the one marked 3
was used with a bridge rectifyer,
The difficulty was, that the set the supply was intended fer (MRD
ex arbulance) required twe separate vcltages and a =34 volt bias supply.
The first was overceic with a relay that conncets the extra 100 welt
winding in circuit cn transrit,
The bias sup~ly was sirpler than expected, A half wave deubler using
large concdensers actually tripled the 12V 4C to =35V the rcquired po-
tential,
As far as medifying the actual set the sub-circuit shcwn shews that
the additicn of twe extra corponcnts were ell that was necessary,
The sct this supply was tailered for had a speaker ete, fitted to
it thus ¢liminating thc handsct, If a higher power is required the
alternate circuit will suit your nceds, This cne used a transforrer
with two 6,3V windings thus clirinating the sccond onc,
It is a switched bridge-cdecubler netwerk and supnlics 400-450V with
plenty of current te back it up.
GRAEME RAND, VK7Z:iQ.
2nd Circuyr NexT MoNTH
2 X 5712‘//00 JAV AC HEATER
/000 4T g‘pVWA - 35V BiAs
N 1000 AT
\l/ — sovi
- -
+2/0 or 320V
: z QOO0 el
= Q
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A
TX /2)‘
/™M RELA
> = > [t/ l Y
~8 L1
_L r:fiRT':-/
AN E Mk E B)‘/Zé//wo
A .
300 HF IRELAY
AddITIONS f7 3ovw
70 SET Rélay Cipeuir
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