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IHE..... WJ... ft£. ^:i.S,.S,,,,/,N.ST,/,T(JI.F
OF AUSTRALLA
TASMANIAN DIVISION
BOX 851J, &. P. 0., HOBART'
JAMJAIff 1964 MONTHLY BULLETIN PRICE 6d
PRESIDENT TREASURER SECREDARY
Mro T. Alien Mr. C» Harris son Mr. K. Spiegel
VK7AL VK7CH VK7KS
Registered, at &. P. O«; Ho'bart, for -bransmission by post as a periodical.
GMERAL MEETING.
•The neirt mon-fchly meeting of the Division iri.il be held in the Club
Room, U7 Liverpool S-fcree-b, Hobar-b, on. WEDNESDAY 8th Januafy 196^. at
.
2000 hours
PLEASE NOTE TIffi GHANOE OF DATE.
Ac-bivi-bies for -the evening have not ye-b been fina finalised
bu-b come along just the same - we id.il have some'fching organised before
•bhen»
NORTHERN ZOM
The nexb meeting will be' held on FRIDAY, 10-bh January 1964. a-b
2000 hours, at 102 Charles Stree-fc, Launceston. Understand -bha-b one
item is finalisation of arrangements for the Zone S-bation VK7NZ •bo take
part in the National Field Day in Februaiy.
NORTH l'ESTEM_^OM»
The next meeting of this Zone iA'11 be held in Laki.us Hall,
Ulvers-bone, on TUESDAY, 7th January 1964. at 2000 hours.
COUNCIL MEETING
The usual Goiu-lcil Meeting for January •will be held in the
Club Room on MOI'JDAZ, 20th January, a-b 1930- hours.
I. T. U . FUND.
We acknowledge uith -thanks dongtionsfrom VKTIff, VK7GB, VK70M
and from -bhe North Western Zone a combined contribution from VK7DA, VK7XL,
VK7LR, "VK7ZA. H, VK7ZAA, VK7BL, VIC7MX and G, Howard. To-fcal in hand is nov :
Northern Zone £3
North We stem Zone 9
Rest 38- 4i 5d
-
£50- /+- 5d
STRAYS.
Gongra. t'Ala'tion. s to Mike Jeimer 'VK7ZAV and Anne Landers who have
recently annoimced their engagemen'b,
And congra'bula-fcions also to Harry Harjano on pgssing his AOGP
and -to Grosby Ru.ssell-*€ireen and Daniel Ford who' have their LA.OGP.
And to VK7AI, VK7DK, VK7SM and Associg-fco Grsg Johns-bon, award
wLnners in the R, D. Gontest,
The Wireless Institute of Aus-bralia. Tasmanian Division,
January 196/+ Mon-bMy Bulletin P&ge 2
TECHNICAL by TO7ZAI
UARTZ CRISTALS.
Quartz ciystals are -widely. used in modem •belecommunications prgctice
as frequency sta'bilising elements and as resonant elemen-bs in filter circuits,
They are relatively simple and robust in con.s-brac-tion-i. and extremely stable in
their properties, Qaartz i-fcself is chemically inert, has extremely low
electrical and mechanicgl losses, and because of its piezo-electric properties
is readily apptied in high frequency elec-trical circuits as the equivalen-b of a
stable, high Q, timed circui-fc, hg'virig a' stability and Q factor much higher -than
could be achieved 'ty con ventiongl means, . . .
Quartz Si02, -bhe most vLdely oc curing ciystalline form of silics,
ciystallizeg in -the ti rigonal class, and well formed crystals have a striking
syT imetry, the form of the ciys-fcal being a hexagonal prism termina-fced by hexagonal
pyramidso " ~ '
Qiigr-fcz occurs in -the tuo forms know as lef-b-hand and rLght-hand. The -bvio
kinds have identical propertiies and physical constants, except -fcha-b egch is -fche-
mirror image of the Other,
Quartz has four axes of ciystglline symmetry, the Z of principal axis
around which it e3Aibits -brigonal symmetry, and -three X axes, equally" spaced. at
120 degrees -bo each in a plane perpendicular to the Z axis. Each X axis is an
a-sa-s of diad or twofold, symmetiy, and all three are, of ccurse, identical and
indistinguishable from each o-fchei-o As in all ciys-fcallins ma-fcerxals, the
mechanical, electrical and optical properties vary id.th direction, the varia-fcions-
being in accordance with the ^yimaetiy. There are therefore small but significan-fc
changes in the elastic constants and in the thermal-e^pansion. coefficient, vi.th
change in the direction of measurement. These variations have important prac-fcical
significance in thgt they penni-b crystal plates to be cut Iiaving'low or zero
coefficient of frequency,
Since -there is hardly any time lag between the gpplica-fcion of -the vol-bage
and the change in dimensions, it follows -fchei-fc the dimensions of a quartz plg-be
will vary cyclically in step wi.th an applied AC. Suppose that a . LF vol.tagais
applied to a qiiar-ts plate and thei-fc the frequency is slowly increased. If •we were
to moasure the current flowLng into -bhe pla-be a curye such gs Fig. l wuld result.
^
^ i- \-
t:A 2
c^., -,u
<^
1": c. , yj
a y
F^fiOofcMC
/
Figol, Equivalent Circuit of a Quartz X-fcal..
_A small current would flov initially and would increase
?!quen,c7_^n a, s:unil9r ma™. ®r •bo the" current into a small1'capacitance?
we^appro^ach closely_to the frequency Fr the current rises sharply. ~re£
.
^maxS1™ ^. ^!._and falls ^P^'to a'mim. inum a-b' a'slightly hi^'
FQ:-?-th. further inc:l:'ease. ln/^quency, it then-increas^s"slowy,^esund!S"i'fcs
^ate.. of incrsase ic.th frequoncy. ' The frequency-'GorresponMng~;bo""inamnum
^!'rent-. is. 'fche reson£sn'fc frequency Fr and that . Tb"the"miniHum"^ren^ is kn^ml Ts
antl;re_solunt fre9uency Fa. " The _sharp dip st" the~anti-re sonant
^..ls. the__x>e5u&-'b, of the sen. es. a™. exhibi:fcing\nductive~reactance"Q^
abov!^he res°nant fre.quency. At the frequenqT~Fa;"the~'^iue"or:bhis ind^il^c
is^equalinmagdi-bude to -fche GapQ ci-fcive-regc-fcance"of''theA 'dTrec1u
^
capaci^nc^between'the electrode represented in ELg. I'ty'-fcho ,CQpacito7ceL.
The frequency 9-b which^a pl^-be or bar resonates depends on7the^mode'of'
on emplo7ed and, the Pl£i'be. (^mensions. For most purposes"fundament8r
.
• !^delare»!mployedi but for-sPecial ^quiremen-fc-s—~especia£lyufor^r
£equenc^es ":-. ove:t>tone modes have been used, othervase'thrplates wulFSr^o,
or too small to permi-fc manufacture,
'.?-prac'fcice any quartz bgr or plate^ has an infinite variety of modes in
can_resona'fce and. its. behaviour can be extremely coinplex. " Fortunately
many_of^he modes can be inhib:i-_-fced ^ i-he choice of--fche'/eic:b^de'systenr^nrthe
.
manner of mounting, or by suitable ohoice of the plgte-dia©nsions."d
The Wireless Ins'bi'fcu.te of Australia, 'EQsmanian Bivision,
JANUARY 1964 Monthly BuUe-bin Page 3
TEGHlCTOAL (Continued)
As the quartz plate has •tiro frequencies of zero reactanGe gsaociated •with
each mode of vibration, •bhe seriesreaonan-b frequency and the parallel or anti-
resonant frequency, oscillator circuits can be broadly divided into two classes;
according -bo which resonance is used. The anto-resonant circui-bs we have all
used, the MILLEE^-PIERCE, and -the s-fcraigh-b FIERCE circui-fc. In both cases -the
operation of the circuit depends on the stray in-ber-electrode capQ citancs of -bhe
electron -tube. The COLPITTS and the GOLPITTS-derived: circuit grG also anti-
resonant circxu.-bs and are especially useful a-b the higher frequencies. Whilst
crystals used at the parallel resonance give results vhich are gdQqugte for most
purposes, it has been siBoim that the frequency of oscillation is dependent
directly on the circui-b CQpgcitance, These capacitances may no-b be very stable
in themselves, and -therefore -bhese circu.i.-fcs do not provd. de the highest degree of
frequency stability which -bhe crysts] Is •bhemselves can provide,
W^en the crystal is oporg-bcd gt i-bs series resonance it exhibits a
relatively low impedance and the effect of the capacitance between its terminals
is negligible, except a-fc the VHF. With sui-fcable circui-fc arrangements it can
therefore provide a stability of frequency at least one order better than that
when opergted in •the parallel mode. The mos'b widely Imov'ai cix'cuit for series
mode operation is the I14E/i.GHAI'I BRIDC33 circuit, but, perhaps the raos't used in
Amateur Radio equipment is -the BULTER, the ROHBKT DOLLAR and the SQUIER, Page
160 of the la-besti edition of -the R. S. G. B. Handbook, Table 1, has some useful
dope to enable you to select the correct cut of crystal
R. D. GONIEST.
It TO s pleasing to SGG that this year's Con-best TO s won by Queensland
Division for the first time, and to that Division -we extend, our congrQ-bula'fcions,
As far as thLs Division WiS concerned the percentage par-bicipa-bion. -waa veiy poo.r
compared -ui-fch other years, and were it not for -the offor-bs of raem'bers of the tvo
Zones, our score would have looked sick indeed.
VK71JI BROADCASTS.
I-b has been decided -bhat for a trial period the call bQcks from coun-bxy
stations -will be -fcgken first on 80 metres as has been -the practice, and on 40
local s-bg-tions will be givsn first preference. This T.d.ll olovla-be the long
delay for locals waiting for the coun-fcry calls -bo fihish.
Vhile on the subject "
keep your calls shorti and don't natter on -•
there are proba'bly others waiting. If you. -want a rag chew arrange g sked after
the Broadcast Officer has finished his round up,
DISPOSALS.
We have acquired Q large qu.antity of various gauges of new copper -wire,
Txi-b the problem arises where are we going to ge-b small spools from to put the
smaller gauges on, as it is nearly all on large reels* Anyone got any ideas?
Most is enamelisii covered. The thicker stuff will be niochine -wound into rolls.
Full details later.
Chas. Harris son YK7C.H
for Bulle-fcin Gommi-btee
The Wireless Ins-titu,teof Aus-fcre. lia, Tasmpnipji Division, '. ' .. :.....
December 1963. VHP SUPPLEliIENT ' By the.. "Voice"
At last the awaited 6'mx DX is with us. During -bhe past fev; days,,.
begining on around the 11-bh Nov. openings have been heard by 7ZAI.
Most cf the signals .were not very strong, but on 21/11 VK4s & VK2s were
worked by ZAQ smd ZAO. Sigs were heard again on 22nd but no contact was
made. On 23rd. the band again oeme good, with 4s and 2s. VK^s h.e.vo been
heard also, but none worked -to date -that I know of.
The Ham Fes-b was .5. success again this year. In the fox hunt held on
the Sunday,. Geof, 7ZAS with ZAI and BB in the wagon with him, came in
firs-b, followed'. by 7DH with 7MY 3rd. Also with Allan were Barney, ZAK,
Dave, ZAY ancL. Dr-mny, ZDM. This fine crew found the fox without he&ring
i-t un-fcil arriving -at the site. l-t appears th&.t Barney has won so many fox
hunts that he no longer needs a recaaver to find -the hidden -fcrx.
S-fc&tions active on 144 at the Ham Fest were.,. 7BL, 7DK, 7ZAY/ZDM,
7KG, 7ZTC, 7ZAI, 7ZAT, 7ZAP, 7ZAS and 7ZAV. Several o-thers had receiving
equipment for this bemd. 7ZAH and 7RL operated portable from M-b. Barrow,
and. were worked by most camping a-b Campbell Town and also by those
remaining in Hobar-t.
On 1st January *64, -bhe 420 mcs bejid becomes available for use to
amateurs, and should get its first real -fcry-ou-t in -the Athol Johns-bon
Memorial Contest a-b the end of Feb. The scoring for this band has been
decided on to help as an incentive to get on -the air. I-fc appears as -bho
we will retain the 50--54 mcs band until the end of -the Ross Hull contest.
However, further notification will no doub-t be given when a final date
has beefa decided on.
Looking forward to some good DX in the Ross Hull Contest, pjid hope
tha-t all those who are able, will take part in same, and forward a log!
Rules for -the Athol Johns-bon Memorial Contest will be forwarded to
the Nor-bh and North West Zones for approval in -the near future, and the
final set of regs. will be published in the January Bulletin.
NORTH WEST ZONE.
Af-ter being heard on the coast VK5ZHL now listens for VK7s every
evening o. t 2000 hrs EAST. He is situa-fced a-fc Mto Gambier and runs 90 wat-fcs
to a Q,QE06/40.
Bob 7ZAA, and Kevin, 7ZAH are having regular QSOs with good sigs both
ways and bo-th have worked -bo Mt. Barrow and. Launceston. Terry, 7TT,
has been listening in v/hile tuning up his 522 receiver.
Den, 7DK, has been heard along the ooas-b with his MOW signal but
suffered bad, QSB.
There should be quite a few stations taking part in the ZL Field Day
on Dec, 8-th, conditions permit-fcing. 7ZAA is hoping to take his station"
up orfbo Round Hill near Burnie. Several assooia-fce members will have
receivers operating on Table Cape near Wynyard. Both locations are over
500 fee-b above soa level and offer good outlooks to the east.
On 20/11/63 Den, TDK, and Len, 7BQ worked, some VK3s on 144.
Signals were around 5/8 and stations hoard included VK3s... ZNC, ZDE
ZNB ;:mcl BW. There were several o-thers, Tsu-fc too weak to read. ?ZBR was
heard Tsy 3ZNG but cont&ct could not bo maintained.
73s -to all for -the coming Festive Season and good. DX in the New Year,
W. Nickols.
I see we are nes.rly'out of room, s^ I will -t;-<ke this oppertunity of
w'shing you all, all the bes-fc for Christmas end. the Now Year". Remember
the ITU fund md make it a Now Years resolution -fco do something abou-t it,
7 3s 9 sco- you- ncx't s'-e&.r,
Lich:'c.l n^or, W7ZAV»