QRM
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Bulletin issued by the Northern P.O0. Box 1010
o - ot
Branches of the Wireless Institute Launceston
of Australia, Tasmanian Division Tas. 7250
August 1977
Vol.7 No.4
Registered at GPO Hobart
for transmission by post Price 40¢
as a periodical., Category B.
_MEETINGS
Aug. 9th North West Branch, Lakins Hall, Ulverstone. 8 p.m.
Aug. 12th Northern Branch, 34 Burke St 8 p.m.
_A.0.C.P, CLASSES
Aug. 8th MODULATION SYSTEMS SSB Kings Meadows
)
, |' Bug. 15th .
JLATION SYSTEMS
MODULATION SYSTI ~
FM High School
Bk B, room 3
/! Aug. 22nd INTERFERENCE
' Sept.l2th TEST EQUIPMENT AND MEASUREMENTS.
¥
Y.R.C.5. CLASSES
YRCS classes are held every Tuesday (during school terms)
from 4 p.m. to 5.30 p.m. at
Kings Meadows High School, Block B, room 33.
_CONTESTS
Aug. 13/14 REMEMBRANCE DAY CONTEST
ATHOL JOHNSON MEMORIAL CONTEST
EUROPEAN CW CONTEST
Aug. 20/21 RAST SEANET WW DX PHONE CONTEST
SARTG RTTY CONTEST
Aug. 27/28 ALL ASIAN CW CONTEST
Aug. 19th Deadline for the September issue of Q R M
NORTHERN BRANCH NOTES by MAC VK7CCC,
The monthly meeting of the Northern Branch was held
at SES rooms on 8th July. 24 members and visitors were in
attendance.
Treasurers monthly report was as follows:
Sales $ 212.00
Other Income S 201.90
Expenses $ 117.00
Closing Balance $1056.50
Next month meeting will be at the NEW club rooms at
34 Burke Street, we look forward to a full meeting, a discussion
by John VK7NJD will put you on the right road to buying & used
car. John is an official vehicle test officer with the RACT,.
Casey's Restaurant is the venue for the next Executive
meeting on 5th August, a very good meal with very little talk,
anyone else wishing to attend please contact me on 918288 ext.64
I'm sure members and XYL$ will enjoy the night out.
Peter VK7PF advised that some test equipment will be
available ex Hobart Airport, in view of an anticipated use of
the club rooms at Burke St. a bid is being made for the gear
for club use. He also advised that from 26th July Novices may
use 28,2MHz to 28,6MHz. All Amateur activities will cease on
the 27MHz band as from 26th July.
Congratulations to Tony VK7TP and Daniel VK7DA on
achieving full call status, good luck with the DX,
Discussion took place regarding Mark Addison, Mark
is paralysed and can only use a mouth stick. Tony VK7TP will
be visiting Mark to ascertain if his interest in radio is
towards Amateur or CB., A decision will then be made, depending
on the outcome, as to what sort of equipment he will require.
Jamboree of the Air will be with us again shortly,
Amateurs who have already agreed to take groups are VK7's,
ZWW, HE, RH any others interested please contact Ed VK7HE,
Dates and times for the JayCees Careers night are
as follows; Preparation 25th August 9.30 a.m. - 5.00 p.m.
Pulic 26th ! 7.00 p.m. - 9.30 p.m.
27th ! 11.30 a.m. - 9.30 p.m.
28th " 1.00 a.m, - 5.00 p.m.
Thats all for now folks, 73 till next month
Mac VK7CCC
Q R M
NORTH WESTERN BRANCH NOTES by Wayne Gibson.
28 members attended the long July meeting at Lakins
Hall, the meeting finished about 9.40, only a few items of
importance were raised.
1) Insurance, it was decided to take out an insurance cover
against loss or damage of the 2metre repeater and beacons
located at Lonah.
2) The repeater is still being harrassed by JUMP IN QUICK
JOHNIES and times itself out, so please ALL users would
you slowly count to 5 before beginning your over. This
will give the repeater a chance to sort itself out and
any other user an opportunity to break in.
3) The Remembrance Day Contest and Athol Johnson Memorial
contest are held concurrently on the second weekend in
August, All members are urged to take part and submit logs.
For details refer to the July A.R. issue and the Bulletin.
4) 1977 HAMFEST, the name is to be changed to TASMANIAN
AMATEUR RADIO CONVENTION to further efforts to improve
our public image. The actual date is still a little confused
but make sure you have nothing on in mid to late November.
73 Wayne
¥ e ke ok ok ek kotokokokokokokok kok
The Editor, QRM
Recently I called a mobile station via repeater
8, in his reply to my call he asked ....'"where are you ?'", as
I was at home on my 2 metre base rig I replied ....'home base"
as I have done many times in the past. To my amazement he said
" cut it out, you're at your QTH",
I was so taken back that I made no comment but decided
to do some revision on procedure so referred to the handbook
for Amateur Operators. It was very enlightening. I admit that
I was wrong as I should have said Fixed Station, but if our
friend cares to look, nowhere in that book will he find any
referrence to QTH, Maybe it is desirable to smarten up our
procedure as there is plenty of scope.
Who calls CQ correctly ? How many call CQ on 2 metres?
Insofar as an Amateur station is concerned there are only three
types, Fixed, Portable and Mobile. There is no such thing as
fixed mobile and it can not be called portable.
Referring again to the handbook, our learned aforementioned
friend should have included in his call .... "operating mobile
from Launceston". If he had done a little revision before making
another operator feel small, this letter would not have appeared.
Rather empirical what !
Max Ives VK7MX
HF and DX notes by Col VK7LZ.
Conditions, like the weather, during July could have
been better, however this is to be expected this time of the
year, African stations which were reported as numerous last
month, started to drop in signal strength towards the end of
June and after the first week in July were practically non-
existent.
The Palmyra Island/Kingman Reef DXpedition is now
ancient history however they left VK's 7HL, 7BC and 7LZ one
country less to strive for, one of their operators stated that
their expenses was well in excess of §10,000 and that the
Palmyra stint alone 5200 QSO's and contacts from Kingman Reef
would be far in excess of that number.
This month a much more sociable DXpedition is under
way,as these notes are being written ZM7AT and ZM7MM are
operating from the Tokelaus Islands using all bands 3.5MHz to
28MHz SSB and CW, One or other of these stations will possibly
still be active as you read these notes,
Wake Island was also activated by WAG6KWG/KW6 on the
15th July but this was a 14MHz SSB only effort and was of
short duration.
The VK7 QSL manager, Snowy Harrisson VK7CH, has asked
me to remind all VK7's to keep their cards to within the
S x 3%" limits, as Snowy said only one oversize QSL ruins
the whole system.
One of the most frustrating things to happen to a DX
operator is to hear DX he/she cannot work and a tune around
3.5MHz produced good strength signals on SSB from KL7, W, VE,
KX6, 5W1 and ZM7 in just over one hour, however only ZMJAT
listened down in the VK band and to work him you had to be
able to use split frequency for a QSO.
Whilst 14MHz was generally down in July, 7MHz did
show some improvement however W stations using CW around the
top end of the band make it extremely difficult to work
DX on SSB.,
3.5MHz SSB STATIONS HEARD
1000 to 1200Z - JA's, KX6, KL7, VE6 & 7, W (most call areas)
and ZM7.
7MHz CW
0600 - 0700Z - zZM7MM, ZP5AL, FO8EX, G, HB, F and OK,
7MHz SSB
0600 - 0700Z - CE@AE, CTI1QN, 3D2RM and 5W1AU,
14MHz SSB
0300 - 0400Z - HR3JJR, VE3HYU/SU, 6YS5HJ.
0400 - 05002 - HB9QK, KJ6BN, TI2FF, WAGBKWQ/KW6, YN1HN, ZK1AN,
and 4X4BL,
0500 - 0600Z - CT1FL, EL3A, IK@JIX, KG4SC, KS6FL, K1IDRN/6CA, TU2GA,
TGOHZ, VE8AM, XE1UF, XF3B, ZE5SJJ, ZE6JP, ZE7JR,
ZM7MM, ZS1CZ, ZS10U, ZS20M, ZS5LB, ZSS5NV, 5X4JE,
SW1AU, 6Y5ID, 9H1FF, 9HI1FG, 9J2WR.
0600 - 0700Z - CT4KR, HIBCDS, HI8GDR, HIBJAF, PAPALO, SVIAE,
TU2GA, VK@CC, YN1HN, ZS3B, 3D2AZ, S9M8HG,
QR M
HF and DX notes cont.
Nothing of note was heard on 21 or 28MHz. As you will
observe listening is restricted to only a small portion of the
day so help from other DXers would be appreciated.
QSL INFORMATION
CT2BB via WI1EP TU2GA via KOKXA
VE3HYU/SU via VEIRU ZMTAT via WB6DXL
ZM7MM via W6FWX 5W1AU via W6KNH
EL3A Box 148 Greenville, Liberia
FK8BCR Box 544 Noumea, New Caledonia
KG4AN Box 73 New york City, N.Y, 09593 U.S.A.
W3HNK Box 73 Edgemont, Pennsylvania 19028 U.S.A.
YB1AQ Box 10 Iasik, Java, Indonesia.
XF3B Box 207 Cancun Island, Mexico
73 Col VK7LZ
K goK o ok K g kok Kook gk ook ke kookok
VHF notes by Joe VK7JG.
The most important event this month will be the R.D.
contest on August 13/14th, DONT forget the Athol Johnson
Memorial contest run in conjunction with the R.D., rules for
this appeared in last months QRM and the Bulletin insert in
A.R. You can use a R.D scoring contact as a scoring contact
in the A.J.C., so if your VHF equipment hasn't been used for
a little while now is the time to get it out and operating.
Several contacts were recorded on 6m during the month.
On Saturday 2nd July the band was open for several hours
although there were not many operators active. Allan VK4ZRF
was worked, I heard VK4ZBE but did not work him and Ross in
Ayre was quite active for some time, he was very weak but was
worked by Daniel VK7DA and myself. Again on Sunday 17th Daniel
worked Ross VK4ZRQ. On Saturday 23rd the band opened for about
20 minutes and signals were very weak, Harry VK4ZHG was worked
by Daniel VK7DA, John VK7JV and myself., It certainly pays to
have that receiver running whenever you're in the shack.
Last Monday evening 18th we experienced a very good
inversion. Kevin VK7ZAH was hearing the VK5VF beacon but no
stations were heard. Kevin did work Steve VK30T (ex VK3ZAZ)
on 2m SSB in Hamilton. Kevin was also active working through
the Mt.William Ch7 repeater, his best contact was with VK2zI
in Broken Hill. So as you can see the inversion covered a
large area and could have provided a lot of activity had
operators been active on the bottom end of 2m using SSB.
Thats all for this month, see you in the CONTEST.
73 Joe
e e K Y K gkook Kk ok R K ek ke Kk okokok
FOR SALE FOR SALE FOR SALE
IC-202, 2 met SS iver, nod condition,
had very use 7000 tontact Tony VKTTP
QR M
PROOFING TOWERS AND BEAM ANTENNAS AGAINST CORROSION
by Harold VK3CM. copied from the June issue of the Geelong
Amateur Radio Club Newsletter.
Many a carefully designed and built beam antenna or
tower has given trouble with corrosion after exposure to the
weather, for no other reason than failure to proof the metal
properly. Sealing and proofing are quite as important as sound
mechanical construction if long service in corrosive atmospheres
is expected of the array. These notes also apply to vertical and
other types of antennas and not forgetting the rotator.
CORROSION;
The protection of metals used in the construction of
antennas and tower is of great importance. In the majority of
cases the matter of protection against weather and erosion
effects is relegated to the levels just below consciousness,
until such time as an element collapses, when the pieces are
picked up to the accompaniment of much blasphemy.
Ask any TV serviceman about this and he will tell you
in no mean words what we are talking about! We have seen the
pitiful sight of TV antennas drooping or parts thereof broken.
Well what can we do to stop this corrosive business,
which is very prevalent in sea-side locations and town and
industrial areas due to fume laden atmospheres.
DESIGN:
Firstly, the choice of adequate material thickness, a
very important item these days of high cost of metals, do not
scimp in this direction or you will regret doing so, if you
expect long life from the antenna system with little maintenance.
this goes for the supporting tower as well.
Secondly the design of the system itself. Many antennas
are built in such a way that liquid e.g. rain or salt spray,
can collect in them and be retained at the point where the
element is attached to the support. This is the point of
highest stress and unless measures are taken to counteract it,
corrosion soon weakens the joint with eventual falling apart
of the element. Where it is difficult to design in such a way
as to avoid these''cups", jointing compound should be forced
into the space between element and support and formed up into
a shape which will not retain liquid.
PRE-TREATMENT:
After the antenna or tower material has been cut to
length it should be thoroughly degreased. Immediately after
degreasing and before the surface can be spoilt by handling,
a primer coat of zinc cromate paint should be applied. This
paint bites into the surface and ensures excellent adhesion.
It has been found that the zinc cromate is extremely water-
resistant and does not curl or lift with the application of
the finishing paint, It can be applied to aluminium, steel,
galvanised iron, copper and brass as well as cadmium plating.
This is important because it is not always possible to use
aluminium or its alloys for every part of an antenna system.
O R M
It is recommended that all metallic components be treated in
the individual state before assembly. The film formed on each
of the dissimilar metals, being a non-conductor will effectively
prevent electrolytic action and cosequent weakening of the
material, do not forget to clean the paint off where electrical
conducting joints are required.
FINISHING PAINTS:
The film produced by the primer, whilst weather resistant,
is only very thin and must itself be protected with a suitable
finishing paint. Ordinary aluminium paint is a satisfactory
finisher, but any good paint or enamel can be used.
STEEL TOWERS:
Ah yes, that steel tower, that rusty hulk standing or
leaning in the back yard, what can we do about that? It should
be periodically inspected for signs of rust as very soon the
metal will be eaten completely away and you will have one
tower on the ground. ‘
Remove any rust by wire brushing or use a rust removing
compound then apply a coat of zinc cromate immediately as rust
will start to form again. Apply one or two coats of finishing
paint and your tower should be proofed against the elements for
several years. Dont forget to inspect all bolts and replace any
that are faulty with galvanised or cadmium plated bolts. There
is another compound "Instant Cold Galvanise'" which comes in a
spray can. This material forms a zinc coating on the metal and
is very resistant to corrosion. No special metal preparation
is required as it can be applied over rusted or pitted areas
provided loose scales are removed. As before, apply a finishing
coat of paint after spraying with this material.
MATERIALS:
Jointing compound - Henleys Green Plastic compoud, obtainable
at electrical supplies, or ordinary
caulking compound.
Zinc cromate - Obtainable at most paint stores.
- e —— o —— oT o- —
YOUR BEAM, WILL IT STAY UP ?
by Harold VK3CM, from the July issue of the Geelong Amateur
Radio Club Newsletter.
Quite often we hear of a beam antenna that withstands
several severe storms and then tumbles down in a comparatively
light breeze. This generally baffles the builder, but a close
examination will disclose that some of the fundamental rules
in the use of metals had been violated., Nearly everyone is
familiar with the fact that iron and steel will rust readily
on exposure to the weather, so proper steps are usually taken
to prevent corrosion, either by painting or applying a
protective coating of some metal, few, however realize that
under certain conditions other metals, for instance aluminium
may become badly corroded.
In the case of our broken down beam, we find that the
tubular aluminium elements have been bolted together with steel
QRM
or brass screws and nuts, brass being used to prevent the
formation of rust. Amateurs are not alone in this, commercial
TV antennas including rotators fall into the same error and
may be expected to give trouble. At each of these joints the
aluminium has been badly corroded and finally weakened to such
an extend that the light breeze caused failure.
Why is this condition bad and what can be done to overcome
it? Lets go back to our school chemistry or maybe the days when
we used wet batteries to operate a doorbell or buzzer. Those
wet batteries used two dissimilar metals, usually zinc and
copper immersed in a conducting solution or electrolyte, such
as one containing copper sulphate. The zinc was the negative
terminal and the copper the positive.
The same thing happens in the dry cells in this case the
carbon rod is unaffected. In like manner, any two dissimilar
metals in contact with each other in the presence of an electrolyte
will form a small galvanic cell and the more negative metal will
be attacked or corroded. All metals can be arranged in a series
according to the individual potential attributed to each. The
EMF developed by any particular couple or combination is the
sum of the potentials of the two metals. The greater this EMF
the greater the tendency towards corrosion. The table shows the
electrochemical series for the more common metals and the
potential of each. In outdoor exposure, the required electrolyte
is supplied by atmospheric humidity or rain. Industrial and
urban atmosphere contain small amounts of sulphur dioxide from
fuel combustion which will slightly acidify the moisture.
Marine atmosphere contains salts which will provide the necessary
conducting electrolyte.
Reference to the table shows that aluminium and copper
(brass is an alloy of copper) are far apart and considerable
galvanic corrosion can take place in moist atmospheres when
these metals are in contact with one another. The combination
will show that aluminium is the most negative of the combination
and will be attacked with resulting loss of strength. The table
will suggest other poor combinations but aluminium and copper
is one of the worst offenders. What can be done to guard against
this condition? If you live near the coast all possible
protective measures should be used. For a dry inland climate
the danger is not as great and less stringent measures will
be satisfactory.
The screws, bolts and nuts can be made of steel with a
more protective coating such as zinc plate, galvanized,
cadmium or nickel plate can also be used as can stainless
steel hardware, All of these are much better than brass but
still not entirely preventative.
As a final precaution the joint should be painted to
keep out moisture and the electrolyte required for corrosion.
Here again the degree of protection required dictates the
materials used. For highest protection, a first coat of zinc
cromate primer should be used followed by one or more coats of
good outside paint. The zinc cromate besides serving as a
prime coat also provides a '"passivating'" action to aid further
in corrosion protection.
ORM
For less severe climates the outside paint alone may
be used. Another fact not generally Known 1s that stainless
steel is not corrosion resistant unless it has a good polished
surface. If dirt or scale is present electrolytes can go to
work and readily start destructive corrosion.
It is hoped that these few simple rules of the materials
may help to keep more antennas in the air and more Amateurs on
the ground.
MAGNESTIUM 1.55 VOLTS TIN 0.14 VOLTS
ALUMINIUM 1,33 ! LEAD 0.12 !
ZINC 0.76 ! COPPER 0.34 !
CHROMIUM 0.53 ! SILVER 0.80 !
IRON 0.44 " PLATINUM 0.86 "
CADMIUM 0.40 ! GOLD 1.36 !
NICKEL 0.23 !
from VK7LZ SUN SPOTS AND THE AMATEUR
In an informative article in the May 1977 issue of QST,
possibly Americas foremost authority on VHF and the Sun
Ed Tilton W1HDQ, reports that in retrospect mid-year 1976
saw the end of Sun-spot cycle 20,
Late in June last year a cycle 21 group of Sun-spots
lasted an entire orbit of the solar disc, the first new cycle
activity that has been seen to do this and as Ed goes on to
say, and I quote "If you sort out the sources of what little
July activity there was and draw curves of both cycles, the
old cycle curve drops to almost zero while cycle 21 curve
crosses it on the way up. Though activity has been mostly
low the rise since has been all new cycle oriented".
As a song writer wrote a few years ago- anyway it went
something like this;
Happy days are here again
Ole Sol now has some flares again
Happy days are here again
So now ther'll be trouble and strife
As some cranks get over rife
But never fear, lets have a beer
Happy days are here again
HINTS AND KINKS
Here is a small parts tray that is excellent for
holding tiny screws, brads, washers etc. The rounded bottom
of a piece of gutter from which it is improvised makes it
easy to remove items that are difficult to pick up with the
fingers. Thin wooden partitions divide the tray into seperate
bins which can be labeled. Attach the tray to a wall with
pieces of wire and screw hooks or nail it to the bench.
A novel and practical way to store twist drills to
promote the best of care, in addition to protecting their
cutting edges from wear and rust. Select a shallow can to
suit the longest drill, fill the can with cup grease and
stick the drills in the lubrication. It prelubricates them
for drilling metal, Before using a drill wipe off the excess
grease to prevent splattering.
Loop ends in wires are made by stripping the insulation
off the ends for a short distance and seperating the wires
into two strands. Then form a loop and twist the free ends
together. Cut off the excess wire and solder the loop to
prevent unraveling.
Nail polish applied across loose ends of sketch pad
pages prevents them from being disturbed by wind when using
outdoors, This will still permit removal of pages.
73
Ed VK7 HE
QR M
Week Subject Date
17 modulation systems A.M. 1st Aug.
18 " S.S.B. 8th Aug.
19 ! " F.M. 15th Aug.
20 interference 22nd Aug.
21 test equipment and measurements 12th Sept.
22 " ! ! ! 19th Sept.
23 wave propagation 26th Sept.
24 transmission lines 3rd Oct.
25 ! B 10th Oct.
26 antennas HF 17th Oct.
27 antennas VHF 24th Oct.
28 basic digital 31st Oct.
29 specialized communication systems 7th Nov.
revision, 1l4th November - 19th December.
The Editor QORM
Dear John and all, thanks for ORM I do enjoy reading it,
I received the latest issue yesterday and it prompted me again
to write, keep up with the news from the Northern Branches,
It sounds like a great deal has happened in the last 4 years.
Amateur Radio wise thing are going slow, the last entry
in the A2CDW log was way back in February in some W contest.
Work is the biggest stopper, it takes up all of my time
between 0530 and 1400 GMT virtually daily and other hours
as well. I have worked VK's 2,3, and 4 at moderate strength
their end, not bad for a G5RV and FL50B. I have been working
on a tower and mast with a 2 element 3 band gquad for close
on a year now., We had a hoisting party about 2 months ago,
if it had gone up ok all that was left was a little bit of
tuning BUT, DISASTER the mast dropped 3 feet when an eye in
the steel rope pulled through the ferule and that bent the
boom, secondly when the mast pulled up it doubled up and bent
in the middle, most disheartening.
I hope to be on the air with the quad by the JOTA this
year. I am also experimenting with a 20m DDDR loop on the roof
of the house, just for fun. HF bands are as follows, 20m gets
congested, 15m is good in spurts and I have even worked Italy
on 10m with the FL50. 40m is virtually hopeless being a
tropical B.C. band as well, congestion is an understatement
although in early afternoon is not to bad.l note a lot of new
names and callsigns, good thing keep growing. My regards to
everyone and I hope to talk to some of you on air one day.
73 CUL Chris de A2CDW
JeT. GUNN PTY LTD
50 BRISBANE St, LAUNCESTON
Telephone 319333
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