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TASMA. Nl AN D (. VISION
BOX 85U, &. P. 0., HOEART
May 1965 MONTHLY BULLETIN PRICE 6d.
PRESIDENT: Mr. T. Alien TEEA-SUKER: Mr. V. F. Bore SECRET/mY: Mr. K. Spiegel
VK7AL VIC7JD VK7KS
Regis-fcerei?. a-t &. P. O., Ho'bart, for transmission by pos-t as a periodical.
GENERAL MEETING :
The next monthly meeting of the Division will be held in -fahe Club
Room, 147 Liverpool St»,. Eo'barty on Wednesday, 5'tho. l'Iay: 1965; a't 2000 hourso
The lecture is to be presented by Iir<> I'lax Burn, •the sabjec-b being " Radio Atds to
Navigation ". As'1.1ax hails from I> C A -bhis shoiild promise to be a very interesting
and informative 'balk,
NORIHERIT Z01'TE s
The next meeting will be held on Friday -the 14-fch^ M;iy 1965, a-t 2000
hourso Unfortuiia'bely, to da-be I have not received any informa'tion in regards "bo the
intended activities for -fcne eveningo The address of the CTorthern Zone Glu'h Room is
The Adul-b Edu.cation Centre, 51York St., Launceston - su.pport your Zone by at'least
attending -the meetings - of course -this applies to all Zones inolu.ding Seadquarters.
NORTH V/ESTERN ZONE :
The usual monthly meeting will be held. In Lakin's Hall, Ulvers-bone
on Tuesday, 4-bho, May, 1965, at 2000 hours.
Vo H. P. GROI1P ;
The next meeting of thG V. H. F, Groiip will TSQ held at -the Club Room,
147 Liverpool St., Ho'bar-b on Wednesday, 19-tho, May 1965 a-b 2000 hours - Vi/liere has
the 'V'. H. Fo scribe gone ? Since you chaps like experimenting I am suro there are many
who could be interested in v/hat you.. are doing - I supplied, you. Tri. -fch some s-fcenoils,
how about i-t ?
COUtTCrL I',IEETDTG :
The May Counoil Meeting 7/ill be held at the Clu'b Eoom on Monday,
17-th., a-fc 1930 hours.
SUGAR - UtTCLE - BAKER - SUG^A _ CBj'ALIE _ ROGER - ITEtl _ PETER - T3RE - 1VS&S. -
OBOE - 1'TELLIE s I believe this is outdnted. '- read vAat it means - is yours ou-fcdated ?
The Monthly Bulletin of the Vi^ireless Ins-ti-ti-ite of Aug-tralia.
Ma-- 1°6s. , ; . Tasmanian Division Pa-'e 2o. .
ELECTIOIT OF, OFFICM8_t
The . following is the lis-t of Officers of -blie Tasraanian Division
with their oorrespoading du. 'fcies being •the result of •fche recently held election<>
PATRON^ L. Crooks VK7BQ
PRESIBEKT ! T. A. Alien VK7AL
.
VICE PRESIDENTS t T. - Connor 'VK70T ; I. A. ITiahols VK7ZZ.
SECRETARY » Ko Spiegel VE7KS.
TREASURER » V. T. Dor e . •VK7JD.
GOUKCIL s "VK7AL 5 VKyK S "VKyJD; VK^OT 5 VK7ZZ? VK7ZAS; VE7EB $ VK7EJ" ( FED' Counoillor )
<S3L Mans. er t VEC7«TB . Divisional Gorres ondent § 'VK7ZAS.
Traffic Officer s VK70M , Publicit s VK7BB .
B«cast Officers » VK7853 ; TCCTZZ ; VK7EB. Mnutes. Secre-bar t XTZASo
/Leature Officer t TOC7LE Bulletin Editor i VC7EB
Li'brarians s D. Pprthouse ; 'VK7ZAS. Technical Editor s VK7ZAS
Solicitor . : VK7ZZ .
Auditors : VK7CV/ ; VE7BJ« . ..
T 7 I Coramttoe : YK7KC 5 VK7DW ? VK7ZJG ; Distribu-tion Gommit-bee t ?K7BJ ; VK7KA.
CTEV7 MEIffiERS s
The following have been refered to the General Meeting as applicants for
mea'ber-ship - Messrs, J» Ro Stirling § P« Aplin ; LLJ., Kno-fet.
T^TOEK t The successful tenderer for the Eddystone 640 receiver recently advertised
in the bulle-bin was &<> lia J. Healey.
ACKCTOVffj EDGEI''ffiNTS t
To VK7EJ, our Federal Counoillor for giving his Easter ( holidays ? ) again to attend
the Federal Convention on the Mainland* Perhaps few realise hot? much -birae and effor'fc
Ted su'bscri'b'es to this thankless task - those who do say Tnz OM s. jolD well cLone,
TO VK7ZA3 5 'VK7ZAI who have de-voted consid.era'ble tirae and effor-fc in oonver-ting -bhe
first shipment. of Taxi Sets for Aaateur use on .6nuc. These sets were purchased for the
Division priciarily for VLSQ on W. I. C*EcI'F. I believo more sets are •to cone and indications
are these tvro gentleaen are prepared to again donft-te -fcheir' valuable experienco in
sonverting thsse also. Again we can oiily say Thanks - truefellows of the Aaatsu.r Code •
SUBS_GRIPTIOIS^ s
Su'h scrip tions up to and inicluding 19<>4<>65» Acknowledgeaon-t and thaiiks to
the following ; VKTZM;. -ffKTDK; VKTTE^ VK7JB; VK7RL; W:7LE; YKTZ^iZ; VK7ZDM; VK7AG; VK7ZBA
VKTZAY^ W:7ZJJ:; VIC7ZBE; VEC7GA; VK78F; VKTPAs 7K7Z.1H;. VK^EC§ VKTZA/*. ; W:7EB; W.JSWf VECTLJ';
VK7GV; W.^1S-, VIC7ED-, VIC7ZBK; VK7ZAT; VK7BL; VK7IL; VKTZBS; VKTLJ^ VK7BZ? VKTIffl; VK7DS}
VK7RY; VK:7I'. IK:5 W:7BR; WITPF; VK7EC§ W.^Wi', VKTTT^ WJZBLi VK7KH; VK7MS; YK7XL; YK:71!X§ VK7EJ,,
continued on Page 4»
The Monthly Bulletin of -the Wireless Ingti-fcute of Australi.a
Ha, 16. Tasaani&n Division. Pa
TECHNICAL 8 „
This mon-fch we have -fco say -thanks -bo Lee Gun-fcher, our very own Yank down-under.
This I believe could, be one of many such -teohnical articles offered by Lee, he is simply
orazy-(-about'transistor and diode'applioa-fcions I r.iean ) . Lee is^one of the "Isack^roon
"boys "at -the University, an ex 17 call sign who has come here -to live. So auch on Lee,
now to ge-fc on to the 'business*
M APPLICATION FOR VOLTAGE VMIABLE CONDENSERS s
c ' .1
4. 6,'
^
- -t
> I -^/V^'VY—^^/-
f-2. -1- >
T
A 1
Voltage variable condensers, varioaps, or silicon capaci-bors, depending which school you
attended ( I shall call them varicaps'- less typing - Ed. ) nay be used in an imbalanoed
or balanced bridse arrangeaent, both'of which are shown above, in using these configur -
ations a auch wider range of capacity varia-tion nay 'be obtained.
" B " is the balanced circuit of course. Bias is fed. through R. Lee has aeasured -the
leakage of the type B.A102, which was at -20V less than 0. 5 UA, therefore R could Tie made
anything between 500k to 5 nego Leakage rises sharply, however at fi -40V ( PIV for all
prao-bioal purposes ) -to 2 uA. It is unlikely though, -fchat operation would be a-t the higli -
er volt age. range, beoauso of the low capacity obtained. A laj-ge value of R will keep load
-ing low on the -fcahk circuit. Notioe with either of these circuits there is not any hand
capacity effect. The advantage of this configura-bion is -fchat the KF vol-tage across the
coil can be appreciably larger -fcha the bias voltage, because the diodes are "back -bo .'back
and when one is foreward biased tho other is reverse biased. Wi-th this arrangeaen-fc
capacitance changes of 10 to 1 have boon achievod, and freq.uency ranges ooapariable with
-bbs broadcast band have Tseen oovorGd..
With -bhe BA102 a variation of 13 -bo 60pf is obtained, fron -20V -bo 0V. and with this
circuit the whole range ooiild T3e used, as lone as the RF vol-tage across the coil did no-fc
exceed about 20V peak ( a'bove -this -the Q of -fcho varicaps decreases ) Since -the varioaps
are in series, the nett diode capaci-by values across the coil would, of course, l>e half
of -the a'bove nen-bioned values.
Cis indicated here -bo merely -to show -that a fixed capacitance can be used across the coil
to pad the resonan-fc frequency to the desired range. Cz is necessary if the bias voltage
contains W components ( ego if it is 1;aken froa a reo-fcified RF source. )
The Monthly BiOle-bin of tho Wireless'Insti-bu.-fce of Australiao
Ma "1 6 . Tasaanian Division> Pa. 'e r.
.
SUBSCRIPTION'S.. .co n-ti naed.
LIessrs ' G. Cannook§ J. Ksrr^; J,. DEu-lin^ R» Gun-ther^ 0. Waldonj
R. McLennan^ T. Inches? H. Kno-tt ( full'aeaber ).§ L. Pretty§ J. Gelston; •J. Van. Galen;
L. Cooper; P. Aplin^ R. Ko Jaeger; H. Westerhoff; G. C. Johnston^ R. -Mann; B. J.. RidaslI?
I. Eadi©5 1L Healy; J. R. Stirlinff? H. A. Vfrigh-fc; G. R. Groapton? F. A. C. Richards; -
R, Jonos5 Ro Balfour; P. Chalko
SATE BLOW FUSES s
The life 'of snail, glp. ss-'bype Ocirtridge fuses doos no-b end. when. the
fuse elenen-b blows. They aa.ke excellent forners for .sUall Vo 5. F» chokes, and when
pigtail leads are sold'ered. to -the ends, -they nay be Qpunted. firaly as a resis-bdr or
cap aoi tor. - WgEV/o
NOTICE s
Have you. soae-bhing yaii wis.b -to sell ? Is there soas coEiponen-fc you req.uire
which see.as iapossiUe to o'btain -bhroiigh -fche asual -fcrado sources 6 ? Perhaps' &
par-b of a wreckod disposal dm. -b'aight be -the ansv/er -to your problon - why not use
WU8. Eulle-tin to advertise ? Any queries ace v/eloome, -t-hQ charges small - use the
facilities your Division offer- -all -this plus a fivepenny stanp and a note could
make you noney or save you aoney -
givQ i'fc soae thou. gh-feB
Thanks to VK7ZAP for -bhe cLona-bio-n oS . p. nod. ulation '-fcr^nsforaer for TKTWI's nev/ TX -
just'''in case you did no-b kno\7, the VK7V/I TX is leaving -fche QRP braGkot ( 150 watts )
Officialdon says we may bocs-b tho yoltago, u.se -fclie presen-t final as s. driver ( who
said -tha-fc ) SGr. ou. nge a raoro "powerful tube and coiapefe with -bhe Mainland Divisions
as far 'as power' is concernedo 'So . Q^.GU.QQ now for coning, on -fcho 3'oast freq.uenoy ..
because they could not; hear us - hi o
Af-ter- the last one I had be-fc-ber- close for this'nonth
7.3
Ted Beard VK7EB
for Bullo-bin: Conal'ttoe.,