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{ BULLETIN ISSUED BY THE NORTHERN ZONES OF THE P,0,BOX 1010
'_' WIRELESS INSTITUTE OF AUSTRALTA TASMANIAN DIVISION L AUN CESTON,
TAS, 17250
OCTOBER
VOL,2 NO.7
e
REGISTERED AT G,P,C, HOBART
for transmission by post as
a periodical, CATEGORY B, ) PRICE 5¢
CONGRATULATIONS
To Joo and Phill on their recent marriage, We wish you much happiness and health
in your future years together,
IR ;KKK
To Dean Lawson for passing his ACLCP, Dean has apnlied for the call VKT7Z.D
KRR
RNHKK
To Norm VK7ZNR for his pass in the recent C.W. exams, Norm has taken the call
VK7NR,
HHF
RHHINHK
MEETINGS
OCT, 3rd NORTH WESTERV ZONE, LAKIN'S HALL, ULVERSTONE,
OCT, 13th . NORTHERN ZONE, TEACHERS' COLLEGE, PLUMER ST,
MOWBRAY, &pm SHARP,
YRCS
OCT, 7th & 21st KINGS MEADOWS HIGH SCHOOL
NOV, 4th
CONTESTS
0CT. 7th 1000z to OCT, 8th 1000z - VE-ZL CCNTEST PHONE
OCT, 14th 10,00z to OCT, 15th 10,00z - VK-.ZL CONTEST C,W.
0CT, 28th to 0th C Q W.W, DX CCNTEST
0CT, 21st J AMBOREE ON THE AIR
G R M
BULLETIN OF NCRTHERY ZONES W.1.A, TAS, OCTOBER, 1972
PAGE 2
NORTHERN NCTES
There were really only two itens 1 d ebout at our September meeting,
Problems pertaining %o a change ofrepeadt gequewcies were alred and the general
opinion seemed to be in favour of a cheng esulted in Australian wide
wiformity, Reports of interstate disse re a little disturbing!
A report on discussions with Clty Couicil officers on clubroom sites showed
that there are likely to be no problems in this regard, The only problem will
be moneyi
Other items mentioned were the proposed WIA constitutional changes, the
Swansea Hamfest snd swidry itcms.
Our trip uwiderwater througn Xen Athertwa'ts slides was tremendous. The
interest and searching -uecticns by merders. coafirmed this,
NOTEWELL,
This meeting 1s at the Teachers (ocllege ((hllege of Advanced Education)
Newnham, at &on,
Be early as the lectur~3/demonstration of their CCTV facilities will be held
before the business wecting, 7ZMS says he'll put some arrows up in case
you're late,
NORTH WESTRRN ZCNE Lo
Lpart from our Sepicmber ncotin ,j tucre iz 1ittle news this ronth,
It was certainly a fine 1"'-‘6131''cg, Ca looking rownd the gathering, one wondered
whether it was North or I T:86, :::1.1&, notable visitors were 7JV, BEP/ZLIAQW,
TNR, 7IWX, 7ZKV, TRH, 7 we cwa 7CE,
A great deal of inforrmation wss forthecoming from all directions., After
the meeting Jechn JV gave a deronstration of SST\/ond certainly stimulated scme
interest, There could be several startecrs in this arca,
It would sceem fronm rerarks heard c¢n the ailr that Tony and Winstone are
making great nrogress with Arateur TV,
By this time 7ZCJ will be accustomed to a new face across the breakfast table
F.B. Joe & Phil and we extend our sincere congratulations from all the boys here,
Back to radio mate,
G U next ronth,
X,
( ADVT,)
SATELLLITE TRACK CLLOCUT.ATCR
27% X 277 Pelar ron with ACC
range rings and Tr“cl»’ (\\LT/S
A
$2.00 peev pa
me,
Ncrtherm Zene ag divisicn, .I'I"‘
P,C. Bex 10 10 Launcesten, Tas, 725
NN AT A NN N ALY A
WORT WL 7
moIRD
AITOTEETR USE_FOR TaA300:
For many years
ofthe Hybrlc valve type. The Zront end
valves and the audio stage L ariver + T2
output transistor.
Due to the recsonable of the power outlet transister
it was decided 1o use outpul stage requiring less
currendt.,
Heving eccuired a 17 I,C, im e enaloyingne TAA300 I.C,
kg
(Produced by the G.A.R.C) I cive same 2 try.
The comzlete including transformers ete.,
)
wvere removed This left plenty of room
Yo mounv the ‘e AMP isdeoigned
AT
Yo worlr invo ¢ Q
G 15 C-M ?
"
use was 3-5 CIIi, wired cliovner-
mountecd same unier the rear WINC OV
The results were cuite enc. I e an assure you that IW of
Audio is ample »dower 2 & car, Frequency response is cuite
B oo
good and it was found vO al ter the volume and-tone
D
o
"‘m
controls to valves Qc vered that a large degree of
"Ton Cut" wes requireaon 1l Tone Control,
4 Eybrid valve vas remove this being the
<
detector and 1st Audio acnlevea by the use
of o small gernwnmum tly across this
C
socket,
4 2
Gai“ of the I.C, I watt outnuv apnrox.)‘wnd
the 100X - 500X J351sfi with.The volume control
is selected o give ¥ 2t meximum rotation of
vhe volume control.
1. Uniform use ol complete rang
2. Prevent extreme overlcad of Termonies!
etec.)
S
h oce occurred, I susvect the
B oo 0 -
9
r
.
o
o nob ei in my »erticular wvehicle is
O
a 1i 3% %.) To keen the battery
O
wn
7ell up. ¥ e 27 OHM job. TFor a
-
o
few weelis now th so heres honing.
Tith reguletors to be 22 “HM resistor
vould be preferable a8 AlT
under meximum sudio outs
The above idesa nly one
a.-« of the the
L Ta
I.C, ALPit
could be put BN
U0
o
DETECTOR - TOIY VKTAX,
@i THA 300 »
CURRENT
byrmn b e BZX70/CV'9/
10K e 28 I'I._ g» 7\ ) i ,
Full Lond
18oMA. /0K A’
A Volur.c eTM
AN G gV )E @
’ o
Qo R M
BULLETIN OF NORTHERN ZONES W.I.A. TAS.
LETTER T0 THE EDITCR r
I have during the past months made quite a few trips to Launceston, FNaturzlly
2
I have taken the rig along and CQed on both channel B and chennel 4, All the
way up and all the way back I have called and celled. Except for a couple of
rarc occasions the only person to answer 1y call is VK7ZIE and I get enough pf
him at home, (HI Ian),
So many times I have later heard "I heard you call but" and I amnct the
only one to corplain of this,
Iny time you come to ocur corner of the Island and call you arc alrost
guarantecd a contact, We don't listen to you calling CQ until the cows come
here - we answer,
You can buy a receiving licence at any post office but rost of you have
worked hard to get a transmitting licence - sc how ebecut using itl
G. RAYD, VK7ZAC
FIH IR0 Nk
FOR SALE
150 watt 6 retrc Transritter contained in 5 ft, standard
rack consisting of pair of 6/40 finals,rcdulator with
pair of KT88 separate sunnlies 750 volts at 5amp each
separate mcters for plate current of TX and 1ICD
3rd rcter switchable tn & pnositions
F.E, T, VFC tunablc over 52 tc 54 Mces
5 €lement YAGI antenna,
ALL READY TO GC. $100.00
VK7ZGT
SR R IR R %R
The Zcne has recently obtained scre Pye Low band I mcbiles, These units will be
balletted, the ballct will clese &pm 13th CCTCBER and be drawn that night,
PRICES ARE AS FCLLCWS;-
15-10 watt ranger robiles Transistor nower supnly $2,00
" 0 " W 410,00
225 watt "
410 watt Victer " " ) " %10.00
1-10 watt Ranger robiles boct rounted with vibrator power supply $8,00
120 watt base staticn 6 chennels $20,00
PLEASE state your 1st and 2nd choice,
Circuits will bc obtained and suornlied with these units,
PAGE 5
CHANGE to the ACC specifications (QRM Sept,)
(a) Orbit details Period 115 mins, inclination 102° to the equator, Height
1450km, 9 o'clock crossing (local sun time),
(b) Launch date 9th, 10th or 11th Cctober 0331 EAST.,
(c) Ne change in 145 95 to 29.5 translater
SIDEBAND SIQTALS WILL NQT INVERT THRCUGH THE TRANSLA’ICR
THERE'LL BE A BEACCN CN 29,450 Mhz AVD 435,100 Mhz.
VK7PF
NONLNS IR
FEFAH AN A N AN
I SNE
M
SATELLITE TRACK CALCULATCR
By P.D.FRITH VK7PF, 181 Punchbowl Rd. Launcesten,Tas.72u
This visual method plots the path across the earth of a satellite and from this
determines 1/ In what direction will it first be heard and at what time (Acuisition
of signal ACS) 2/ The bearing, time and elevation. at closest gppreach (TCA) and
3/ The loss cf signal(LOS) direction and time, For co,,unication purposes it is
required to know areas of possible contacts, These can be fownd by using overlays
for the particular areas and cstablishing whether there is a comron overlap pericd
wnen the satellite is within range of both stations,
Befcre going inte details scrme terms used in tracking satellites will be given
and explained, When the first Cscars were tracked I had difficulty in finding a
sultable text to explain in just the right amount of detail the mechanism of how
and why a satellite orbits where it dces and Ref, 1 is tc be reccrrmended as that
text,
Crbit A satellite is in orbit when it rewclves around the earth in a
plane which passes thrcugh the carth's centre, This means that it has to spend
time in both the ncorth and scuth hernsnh+rcs, it 1s net possible tc crbit arcund
say 4075 latitude cnly,
Crbit nunmber The start of em orbit is said tc be when a satellite passes
over the cquatcr on a north bcund track (ascending ncde) and the nurber cf the
crbit changes at that timc, It will be seen Trem the calculater that it alsc
passes over the equatcr southbound (descending ncde) approximatcly 180° further
west,
Inclinaticn This is the angle the planc of revelution makes with the
equator at the start of an orbit with east as reference, For ACC this will be 102°
which is the angle required fer the chesen height to cancel the influences that
would move the daily viewing time away frem the chosen 9 o'clecs leccal sun tinme,
Prcgression cf tracks The nlane of the orbit in which the satellite
revelves can be regarded as fixed with the carth rotating benecath, This means
that successive cquater cressings in the same direction will be further tc the
west and because of this the longitude scale on the equater is marked in degrecs
west only.
Pericd The time of one reveluticn, For earlier CSCARS this varied Tut
the changes will of he of no ccnsequence for ACG,
Predicticns . These are usually given as orbit nc,. the of thc start cf
this crbit (as it crosscs the cquator ncrthbeund) and the longitude west of this
cressing,
The calculator This ta:cs the form of a pelar map, that is, a great circlc
map with the scuth pcle as centre. Twe sample tracks are shown cn fig, 1 cne scuth.
bcund east ¢f Australia and thc cther northbound in the sare area, The first weuld
be arcund Bar, end thc cther arcuncd 9pn, - The tracks arc actually great circle
paths ccrrected for the: Earths rotaticn as the satellite roves along then, The
nerthbeund track crosses the cquaterscuthbound at 006 5CW, passes to the east of
the pole and ncrthwards te crcss the cquater at 200.9w (006 54+ 180 + 14.4) eand
intc the next crbit,
The scuthbeund track crosscs the equater 7 crbits later at 207,5°W, passcs to the
west of the pcle and then ncrthWQr@s tc crcss the equator at 41.9°W (207.5+180+14, 4o
360). The carth rctates 14.4° during half an orbit cr 28,8 far a full crbit cf ACC
(115 min. pericd + 4) The next N-S crossing will be.at 236,3°W,
Shown in fig, 2 are twe sarple range diagrams which have tc be used for the
particular latitude cf interest. The ones supplied with the tracking kit, being
made available, will be fer rost latitudes and be on transparent paper. -
US]NG THE CALCULATCR
Selecet the range ring for your latitude and fix it cver the map with the
centre at your locaticn, or better still cony it cnte the map tc leave the trans-
parcency frec foo use at cther locaticns, Fix the map onto a bascbcard of heavy
cardbcard cr other suitable material end the ACC track cnto a piece cf perspex,
Pivet by scne means the perspex with the indicated scuthnele at the scuthpole of th
map, New you can de a trial run of a typlcal day's cycle of crbits, Retate the
track so that the sturt cf an orbit is at 1’73 W and assume the time is 1900 EAST,
Study the track and sec that et 1 hr.42m, after thc start it passes over ZL and te
the cast of VK tc cress the equatcr at 201.8°W at 1955 hrs, Now rctate the perspex
sc that the start is now cver 201,& W tc see the track for the next crbit, This
will ncw be over VK and the times between ACS and LOS can be scen fren where the
track crosses thc rangc ring, centred on your lccaticn, 2t the 0% elevaticn ring as
well as the intermcdiate becarings and times, Try the correct range ring fecr cther
lccaticns tc see the arcunt ¢f cverlep and whether the satellite will be in this
cverlap and at what time, Continue tc retate the track arcund in 28,8° increrents
to seec the cther pertien cf the track that gees N..S, Continue to rotate the track
arcund to find the next day's crbits, These will not be in the samc place but
will appear tc be further tc the west and later by 55 minutes, but a pattern can be
derived tc make day tc day predicticns, casicr,
Orbit time w Frcn the exarple it will be seen that
100 1800 173 the tracks will be alrrst in the sare
101 19 55 201.8 pesiticn every seeend day and 5 mins,
S AT - carlicr, This may nct be whclly truc
113 1855 186,.7 in practice as a variaticn of the
M4 205 215.5_ nerinal peried of 0,1 min, will alter
125 1745 171.6 the tirme cver twe days by 2.5 minutes, .
126 1250 200.4 The predicticns can of ecurse be updatec
139 2045 214.,1 by the tine differences found in practi
140 220 242.9 .
USING THE PREDICTION INFORMATICN
Generally follcwing a satellite by bean swinging for maximin signal is
wnsatisfactery, especially for the lonc operater whe may be atterpting to make
a QSC at the same tirnc, Duc te the relative brcadness cf a tynical 2XMhz bean
ccrpared with the asscciatcd 144Mhz bean, when using ACC, a goed signal cculd
be received when the 144 Mhz becan is off the pcak fer transmissicn inte the
satellite, .
Te prepare for a particular pass, frem the calculater find the bearing and
tires at ACS end thence at twc cr thrce minute intervals up te LOS, Start with
the aeriel arrayat the first bearing and step it arcundat thc cerrcet tires tc
the predicted bearings., Continue tc de this cven if the signals are weak cr
ineudible, The cquiprent scteup should ensurc that the 2Mhz cutput can be
renitered while transmitting cn 144Mhz, This enables you te listen for your returr
signal frem the satellitc and a check can be madc cof the cerrectness of the bean
hecading if decdircd,
S WA RI;NH N KRR
I WISH TC TMANK L.Dcwl VK7ZLD for his work in drawing up the calculater and fer
the enccuragerent given te re by cther local anateurs when shown the calculater
in the erbryo state,
References 1 Satellites & Scu.ntiflc Research, Desrcnd King -
. Hclc,
The Cscalater CQ August 1965
CSCAR predicticns, March 1965 Peter VETPE
.R.M
:
BULLETIN OF N ORTHERN :
ZONES W. I. A. . TAS OCTOBER s 1972
Page 7 '
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