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BULLTIN ISSULED BY (Hi NOLIHIRN P.0. BOX 1010
BRANCHZS OfF LHE WInsuedos INSTITULE LAUNCESTON
OF AUSIRALTA, TAS. DIVISION. TAS. “2T250.
August 1975
VOL. 5 No5
e .e 0 7. e e .t eB 8
PEGISTERED AT GPO HOBA.T
Tor transmission by post PRICLE 40c
as a neriodical. CATEGCRY B.
MEETINGS
Northern Bxecutive mesting
Northern Branch Civil Defence Rooms
Bourke Street 8p.m.
Korth West Branch, Laking Hall, Ulverstorne Bpnm.
Y.R.0.5. MESTINGS
th
O
Kings Meadows. High School 10am.
23rd
9th
Lakins Hall Ulverstone 2pm.
23rd
CONTENY.S
9th-10th Buropean Cu.
16th-17th Remembrance Day
23rd-24th All Agian CW.
August 1975. e : 0L R.ME ~ page mno. 2
Editorial
The Remembrance Day Contest will be on again shortly:
in fact on the 16th and 17th of August. This contest
involves a perpetual troyhy which is awarded annually for
competition between Divisions of the Wireless Institute of
Lustralia. It is inscribed with the namegs of those who
made the supreme sacrifice and so perpetuates their memory
throughout Amateur Radio in Australia. This contest is
known as "the friendly contest" and so, I hope, it will be
again this year. It is disappointing to see that repeaters
will not be allowed (except for satellites) but Rule 11
does mllow for skeds to be made using repeaters and this
should help V.H.F. operators to some extent to gain more
contacts. So V.H.F. operators drag out your tunable gear
and get it ready to help the Tassie score this year and
if we can get a large participation we should be able to
bring home the trophy. A loo! through the results last
year and comparing it with logs of the contest show that
gsome operators did not send in their logs, so please enter
amd more importantly after you have send off your log to:
Regembrance Day Contest,
Federal Contest Manager,
W.I.A. Box 67,
East. Melbourne, 3002.
This must be done to enable it to reach there by Wednesday
17th September 1975.
73's and good luck,
Graeme VKTZGG
Looking Back
Extract from Minutes 11 July, 1958
"7LZ proposed that we write to ARRL as Lord Howe
Island has been made a separate country that
Tasmania likewise be so recognized. Would also
suggest that we deal with ARRL and that a copy
of page of A.R. Radic T.V. & Hobbies (both giving
Tas official status)be forwarded to press on
ciaims.
Extract from Minutes 8 Sept 1955
."We are pleased to receive the uews that EJd Bovis
has now received the call VK7ED, Transferred fram
——
S
Aug 75 Q;R;M. page 3
| vl A
Northern Notes:
These notes will be brief this month as I was unable to
attend the meeting and have gleaned comments from those
who did attend.
It would appear there was soue discussion but no decisions
reached regarding the thought by some that the meetings
are too formal and regimented.
A tour of the Lxeminer was proposed in lieu of/or as well
as the October meeting (tour to be on a Wednesday night)
and further discuscion on this will take place at the
next meeting.
A letter ha: been sent to the Launceston City Council reg-
uesting specific details regarding terms and conditions of
leave for the clubrooms. We hope to have a reply next
mecting.
It is a pleasure to welcome three new members, these being:
Stuart Beveridge, Byron Delworth and Harvey Skegg.
It appears that callbooks will be published on a yearly
bagis thereby doing away with inserts.
The Byelaws are now being printed and should be available
at’ the next meeting.
The next lecture arranged by Wally VK7ZWX will be given
by dr. Green from Yeedon & Co. on Stocks and Shares (we
should be able to make much money after this lecture.)
T3s Graeme VKT7ZGG
NORTHFRN BRANCH EQUIPMENT STORE
CHANGE OF ADDRESS
DANNY APTED
2 DEAN STREET
RAVENSWOOD
PHONE 391069
P.S. He even has a colour T.V. for you to view while
your order is being filled.
August 1975 Q.R.M. page no.4
North West Branch Notes
Amazingly enough it seems like only last week that
the last notes I wrote were sent in. Still down to the
nitty gritty.. Our July meeting did not really go with
a bang as our new treasurer VK7MX was unable to make it;
this cambined with a generally poor attendance made it a2
fizzer but this was made up for by a very short meeting
and ithus time for a2 good natter among members after-
wards. Enpough with the last meeting, the next one is
comming up soon and we are having a Junk Night. So if
you have anything to dispose of from dud finals to wheel-
barrows bring it along and we will auction it off.
Remember no junk, no auction. DILimit of 1 truckload per
member.
The North West Branch has appointed a committee to
get a local repeater under way and this committee has
really been moving. A sight has been found at "Loana"
just west of Ulverstone. A local construction firm has
built and donated a prefabricated shed for the site and
power has been arranged. The shed will be installed on
gite @8 soon as the weather will permit. (We hope it
will be up by the time you read this.) Construction
has started on the actual repeater but at this stage
the committee is consentrating on the shed etc. One
last note is that a collection is being taken up locally
to pay for cooking lessons for one of our younger
members. Seems he spent a short while in hogpital with
food poisoning, only a mild touch though fortunately.
Till next month
A.B.C. WARNIKNG ON FM RECEIVER TUNING RiNGEeXtract
The following warning on FM Broadcast receivers has
been circulated by the broadcasting Control Board.
SIR .
The Aus%rali an Governme nt has accepted in-priq01p1ethe
reccomendations of the commission of Inquiry into FM
Broadcas ting in the frequency range 88-108 Miz.
The commission has reccommended that the televised
transmissions operating within this frequency range by pro-
gressively transferred to other channels, with CH. 5 to
Ch. 5A to (101-108 MHz-) being cleared first, followed
after some years by Ch. 4 (94-101 MHz) and at a lat:r date
if necessary, by Ch. 3 (85-92 lHz) : |
Action is currently being taken to transfer the New- |
castle national TV station from Ch.5 tc Ch. 5A to free |
the band 101 108 MHz for FM transmissions in sydney and
newsastle. It is therefore clear that the initial devel-
opement of FM transmissions will be in the 92-94MHz and
101-initial of 108 MHz ranges.
All parties are therefore warned that FM receivers des
ing for the domestic FM bends in Japan (76-90MHz.) or West-
ers Burope (87. 5-104MHz). Will be unsuitable for reception
of the Australian FM transmissions as now licensed or being
lanned. Interested purchasers of FM receivers should be
advised that only those covering the whole frequency range 88—
100MHz. will provide adequate reception.
= |
Auzust '75 QR Page 5
HF _NOTES. JULY. De VLBC.
Conditions have been erratic on the hizher bands this montu
with the lower three providing wmost of the listening mostly
during the hours of darkness.
160 iletres. CW from last and west W land, and some JA has been
heard during the cvenings at about S3 tc4, with wainiand Vi8s
i
above tne 59 mark. No phone was hecard.
30 lletres Good strength CV and ~houne gizn-sls heard from W
and Oceans during the evenings at weekends.
40 lietres. DIutopean and W stations hecard most days CW and
Phone earkymornings and late afterncons with plenty of
activity probebly fallout from the lawroe holes in the higher
bands.
20 lletres Openings ap De ar to Le Dbeccoming suorter as the year
passes, not a lot of ac tivity was noted and little heard of the
two ARKL contests an d even less of the two south awmerican
OIlCS e
Short openinss at around 2100/¢300u and betwcen 0300/0600z
secuned Lo be the orJcr this month.
15/10 lletres. These bands have not been tuned this wmonth
[ s s o sI A e
from this QTH, however, with a2 tri b.nd Cuad on the stocks
more may be he.rd next wonth with a 1ittle it of luck.
The RD contest should promote souwe increasge in activity on
the HIF bands thils year, with CJ counting for double points the
bands should come to life for one weckend. If Robin dusts his
key and John clcans his camera, Col :nd Zen their mikes. An
if Peter gets a fix on the space debris the RD tropay is as
good as back in VK7,
7BC received the first Calgory Centemnial awcrd issued to VK
this week, it's quite a nice sheepskin voo, specially as it
does not require any IiC's Hi.
73 de TBC. Trenmi..
*¥#¥TOR SALL***FOR{ SALD***TOR5.TI**¥FOR SALL***
1 only Commercial CRO
zood to 400 Lhz at -- 3dB.
1 only Victor Pyrox Henimatograph
early model 106mm. sound projccior.
Both items in working order but need some attention.
Reasonable offer will secure.
Frank Richards.
Last Tamas Highway
Dilston
Phone 281333
k
Lug 15 QRM page 6
VHF Notes By Joe VK72GJ
There has been almost no activity on both 6 and 2 metres.
with only the FM channells being used. To help promote VHF
activity the ATHOL JOHNSON VHF contest will bc held in
conjunction with the RD contest.
RULES FOR THE CONTEST
There shall be one division, transmitting open.
All times in G.I commencing 0S00GLT 16th August to 0759 Hrs.
GMT sunday 17th August. '
One point per contact per band may be claimed. ‘
When using M a contact via any other moD: is worth 5 points.
A station may be worked every two hours.
Repeaters and satellites may be used.
CYPHERS: Before points may be claimed for a contact serial
numbers must be exchanged and acknowledged. The serial number
of 5 figurcs will be made up of the R.S. reports plug 3 figurcs.
Numbers exchanged for the RD may be used for scoring in this
contest.
All log sheets shall carry callsign;. ..
Name,
Address
Score Claimed
Type of Equipment Used.
And a declaration "I hereby certify that I have operated
in accordancc with the rules."
e s ee e se o e e e
Date
All logs to be rcturned not later tham one month after the
contest To
The VHF Officer,
P.0. Box 1311
LAUNC._STON 7250.
We trust that you will enjoy yourself doing the contest
and don't forget to return a log both for the RD and the
ATHOL JOHNSON.
138
Till next month
Joe VKT7ZGJd.
cust 1975, CRM Page no.
Ladies Page
Ginger Fluff Spongze
2 cup sugar
4 eggs
Pinch salt
dessertspoon golden syrup
ey AN s
cup corn flour
teasp cocoa
teasp cream of tarter
Teasp carb soda
PO WO
dessertspoons P. flour
Beat eggs & sugar & salt well. Add golden syrup & beat a
few wminutes longer. 3ift all dry ingredients 3 or 4 times
together. then add to’' egz mixture. Divide into 2 sponge
tins & bake in hot oven for 1% to 20 minutecs.
% W N € ¥ N
Iecipe for g Growing Boy
Take a scattering of Freckles,
Across a little Nose,
Add a pair of well scuffed Shoes,
some patched & muddy Clothes,
Mix in a sandy crew Cut,
Iyes of laughing Blue,
Sunburned cheek, a toothless Suile,
Grinning up at You,
Then stir in cuts and Bruises,
A pocketful of Stones,
And add o large Capacity,
Por lollipops and Cones,
Measure shouts and Laughter,
Add feet that can't be Still
Tend the mixture well and Watch,
with loving care Until,
At last the Precious Mixture
is finished, and you can
Be sure that restless Little Boy
Will be a fine Young Man.
#.W
WW K *
Noelene XYi 1d VXTHE
Iy apologies to Noeleme, +v.uc 3Bziacuc Loaf and Pumpkin Pie
in the June issue were also contributed by her.
(Zditor)
August 1975 Q. R, Page No &
Co-Ax1
g. Cables. Part three(3)
Last month we started by looking at some of the definit-
ions applicable to co-axiel cables, spoke about some of the
difficulties of manufacturing and gave a personal opinion as
to what happens to that expensive bit of co-ax you bought if
you don't give it the care and attention it deserves.
This month it is proposed to disgress further on defin-
itions and on cable care.
Power Rating and Temperature.
Power rating which is another important consideration
is related to the over all size ~f_.the cable and is signif -
icantly influenced by the value . =.
This is the governing ratio, gssuming matched lines and
optimum ambient temperature of 40¢°
In these days of using co-ax to jump from, say, driver
stage to output sta.e it would be well if heed was taken to
choose a piece of cable with dimensions large encugh to carry
at least 50% more power than you expect to zet. Phe writer
has seen many a peice of equipment ( and this applies also to
receivers) not given of it's best because a nice piece of small
diameter co-ax was used instead of something a bit bigger.
Miniturisation is all very nice but not very efficient if you
dissipate your power between chassis in the connecting cable.
Look at some of the plumbing in UHF and SHF installation, its
not always used to prevent attenuation!
Conducter temperatures of polyethylene dielectric co-ax
cables are pperated between 65 C and maximum of 80°C.
Look at the following table to give you some idea as to
what happens to power in relation to ambient and conductor
temperatures.
Lot
5o
«0C .
/D3 7s 72 7, >0, ZE
A
Taking RG 17 as an example ghich has an approx. power
rating og 930 watts a# 500mHz at 40°C. If ambient is expected
to be 50°C we must derate to 75% giving us only a power rating
of 700 watts.
Go back to your inter connecting cable of 0.15" outside
diameter which you hope is transferring 1 watt to the Power
amp stage. Got the message. Smell something cooking! Note your
power is lower than calculated.
V.S.W.R.
Another very important consideration related not only to
power but to attenuation is Voltzge Standing Wave Ratio. This
is the ratio of the voltage maximum to voltage minimum existig
on a co-axiel cable.
7~ J
August 1975 Q. R.M. Page No 9
Page two (2
It occurs whén,there'is discontinuity or mismateh to the cable.
i.e. Don't use a 50 ohm lcad on a 75 ohm system.
Any variation from the theoretically ideal c.uses a
reflection of the incident wave. The reflected wave and incident
wave roduce a standing wave.
For maximum energy trahsfer, the importance of this
relationship tecomes most apparent.
In many systems a VSWR of 1.3 maximum can be tolerated,
but the lower the VSWR the better becomes the finished systein.
To understand this better.the reader is referred to any chart
showing VSWR power loss.
Some examples:- A VSWR of 1.6 results in 5% power* being
refelcted. A VSWR of 1.9 results in 10% reflecticn. The
scale is non-linear and power loss goes up r:pidly with small
increases in VSWR. 2%
One of the difficulties in obtaining a low VSWR is
readily seen when one realises that ths VSWR of a component
can be better than the VSWR of the wheole system. This can
introduce "Lumps" into a radiating system. i.e. the VSWR
L
varies at different points. :
These "lumps" are und:sirable, they have been blamed
for causing epurious cmissions from transmitters, or it may be
L more correct to say that they do nothing towards attenuating
as harmonic allready on the line. Rectification of siinal on
the line is another prcblem traczd to "Lumps". The only sure
. cure for this problem is to try for an ideally perfectly matched
system of load - (connectors and cadle.)
L
The author trusts that this series on some of the problems
associated with co-axial coable has been of interest. During
my researching I'have certainly refreshed my memory.
So far it's all been theory, next month it is hoped to
publish details of a simple materin; device that can be built
to measure impedance of feede s and aerials.
The writer would like to thank my friends at S.T.C. Pty. Ltd.
and Standard Wire for all the help and assistance given.
L +. 138
L VKT7NR
A, Richardson.
o
E
7
!
JaT GUNN PTY. LTD.
50 Brisbane Street,lLaunceston.
Telephone 2 2251
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: Telephone 443119
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