SKM C450i23080810580
Recognised text
Text below was produced by optical character recognition and may contain errors. Check it against the original.
THE WIRELESS INST I TUTE 'OF AUSTRALIA
TasmaniaxL Division,
Box 851 J G. P., 0.,
HOBART.
MONTHLY BUffiETIN mjj^s 6d. JULY,,. -1960._
"^ci'-rt
ERESIDETT . TREASURER. SEORETAEY
I/ir. - T. Alien Air. 0. Harrisson Ivlr, K» Mi'lltn
VK7CH. VK7KA..
VX7AIi
.
Mee-biT." P'lacs - 1^-7 Liverpool S-trse-;.-, Hobar-fc.
Go-nmencing this month the _Monthly_ Bu:. letin will take a dlffferent
form, to put'infco effect a decision of Council a.1 follows :-
Tt was decided tc puMish a periodic;a to be . known as the_
Bull 3 tin"'3f^the "Wireless Ins-^tute of Au;, tralia, Tasmanian Division,
Isiuesl"^"be'made'men-bhly ana all copies _posted -. 0 -bhe ^priv. ate^addres^e^
of"Members, -fco-be forwarded regularly. The price of 6d t. o, be inoludecl01
theA"'anmai. 's, ibscription. Six sM. llings
'. per annun from e&ch_Memb^^,
sub3cript;ion~shall L^be pu't ap&. rt -for the Journal ^md to^be^separat
accounted-fcr in.''tKe Annual" Ealar. ee Sheet, .. find'duly aua?,fed. .
This will" enable the pcs tag.® costs on the Bulletin -to be
L^- reduceTand-wiil-also'tend to. make. the Monthly ^Bulletin ^rnore^^
interesting', "and'we wili include in ee. ch.. copy^ some , t'eolmlcal^ltem^
kiave'aS- ideas'in--thrs regard I "will ^be^pleased t'° hear_froln^oaa.
HoSe"the cir. cuit~for"fchis-month . ^rns out all right, only got a Biro pen
to do' it wiJA hi.
NEXT MEE.TTN.C. ;. The . next G-eneral,, Meeting will be held at the Club Room3,;
1 Live.ppccl Street, "on July. 6fe<, ' at 2000-.. hrs» 0
LECTURE:: The Lecture this month will be a recorded talk^-by
I-^^FMadeley, who la'the: Divisipnal-Engineer, _ T. V. __w^h_the^P. ^G. ^^^
lCentrall "JSff:c^; "Those oFyou'who" fortunate ough^to . hearer. ^Madeleys
were en
P?evi^sutairw ill"k^w"the''qual'it7-ofjhat^ SK^v. r«".
Refieiver".
^Mr^peu S^equal. t7"'a3 intereating. The subject -'"Buying a T. V.
. f '. : ..
NORTHERN ZONE: The.'hext Meeting of this Zone will be ^Idon^July 8th^
2u^hrs. "i^b. jG. A:'"'A'demonstration'- of equipm^ arranged by Mr.
will be" given. . 'It should, be an interesting night.
NOETH-WESr[EKN ZONE: TOie next Meeting of this Zone wlll. be held at^Lakin's
S-ail7-U^ERS"r6Nfi, ^on Tuesday, ^ly^thc at_the^3ual^. ^me^ ^ m^7^8,
lp^^b:L^^ur'a''few more^are^riged" to attend ^3, _Iy[eetin^and^h^ma^^r
Sfc)othr^qurp^nt 'for the''Burnii~iFire "Brlgade^^^hich is^be^ng^onst. m.^d,^
that all hands ..
Membe?^lofw the'~Zone7~wiil"be MAX discuss ed. requests,
rally round and give a hand in this vsry worthy project.
S. W«L. GROUP: This Group: will meet as usual on the sec'ond"Wetoesday^in.. *^
the"month'a^'the Club RocraSo I have na information^regardi^g^actl^ities ;
sch eduled for'thls'Meeting/so will you please go along to find out.
VoH. F. GROUP:' , This Group's Meeting will beheld on ^e_third wednesday
a'^the ciu^~Roonis,"~Again7l have no^informatlon^regarding^thl^Group^^^
^parlt°f^ the^ct ^at"Mr^A7-Morrisby_has_a^rang^d \o^^°^e . a^^ber .:
^FRLIS'valves/"If jcu'require any please °o"^ot-M^ ^r,risb7' . r%7«i<,.
wSllFS P?lcera ^4/^e^^d~are7'I^e3^e^u3able^at^576^Me^^^^
£asJ'autr£nsmitter operating~. Ln- ^e6'»4 Centimeter Band. . Would1 nt need
much space for a real super beam antenna for that one, ALAN.
As from July 1st, Amateur StatiQns in the Borthern
Territory will use"the~prefix"VK8 in lieu of the VK5 as at present. rPhe
.
-2-
call signs are as follows :-
VK's 8AE. 8AS. SEW. 8GU. 8NE. SOW, 8PL. 8ST. QZG- & 8ZW .
This names and addresses will be notified. in the new Call Book.
REMB\IBRANCE EA.Y CONIEST: As YOU will have noticed, this will be held on
Augus 15th.. l4 hnext. With YOUR help Tasmania won the Contest last year
and with YOUR help we will retain ±t fchls year. Log Sheets wiil be'forward-
ednext month to those who require. them and if you will let VK7WI know,
JACK will_pass the info, on to me. I have 1, 000 aheets so if~we-fill"that
lot^up will be very jFb, _ Last yearns effort was really good. Of ali-the'
Stations on the air, only one operator failed -bo forward a log, which does
seem a bit pointless, having put in a lot; of time running up a'score* So
this year I-et^us have everyone on and ALL put in a Log, ^Even the Z-.Call
chaps have only to ja^xxx;h±A work 6 stations (on the mainland) and they
can also^shoot_in a Log» May be a bit difficult but who can'say it ia
impossible? So get that; gear checked over and let us retain that Trophy,
have an enjoyable time in the Contest, and if the worst comes to the worst,
lose it as actively as possible
-.1
Well, here goes with the Technical article which is taken from
QST, the Author. -, one JMES:-A.. MURRAY, Jrn. W4TKR*
Refering to the aocompanylngd hope) circuity the 5, 5 Mc/s'Xtal is use.d
on the.:, 3rd, 5th, and 7th« overtones to cover, respectively, 20, 15 and 10 ';:
meters. t.. Oscillator switching is accomplished by switching . brimmer . - .. .
oapacitors. in the Butler osc7 tank circuit. On" all these'~'bands fche
receiver tunes forward since the fixed conversion osc. is on the low "'
side and the i«f« starts at appr<»x, 5. 5 Me. Since the overtones are",
not harmonically related to 5, 5 Me. there is a slight displacement"®f
the lower band edges from the 3. 5 Mo. tuning posi-bion of the'receiver.
is. ;;am^unts_ to.. about 8 Kc, for 20 meters, 9 Kc. for 15 meters, "and"
10 Kc,.. ofor.., 10 meters 'with the 3505 Kc Xtai in use.
It is interesting to note that; the 7 Me* Kband could be beat down to
5. 5 Me, by^using the fundamental frequency of the Xtal, but the". so»
signal _would come 'diT lecfcl7 through _the mixer at'the Xtal frequenc. y."
and_so would the second hamonic~of the Xfcal which falls
:
in-. the--7t 'Mc,
band, ^ Three possible solutions suggest themselves; One is touse a ',
second Xtal^. somewhat . lower than 5. 5Mc. for the TRIc. band only. Anothe]?. . i-v
±ato.. s-CGQPt more ofa dispersion of the higher frequentey bands and .
uso^ a ^single Xtal with a frequency a little'below 5,'5Mc, " The third
method would be to use a ZAal with small dispersion"among the. hlgh-
frequency_bands but^one which would permi-b tuning 7 Me. with the^osc.
on the 3rd. over tone (about 10, 5 Lie. ) "In thla case the 7 Me. band would
tune backwards-;, frcm abou'u 5. 5 to . 5. S Me, It haa been assumed'that' ...
.,.. ;fche overtones will be lower than the harmonics of the fundamental, as
is generally the case.
. A^ converter such as this with some 7 c. provision wcnild be a . , ..
Valuable accessory for one of the 3-6 Me, Gommand receivers*
W4TKR's single crystal oscillator oircuit;
for covering 14, 21, and 28 Mo. in a'Xfcal'
converter. ;. The osc, tank circuit- should
tune to the osce fre'q,, 'in each case -
approx 10. 5 Me. for 14 Me, ; 17. 5 Me. for
21 Me*jand 24, 5 for 28 Me, ' Separate tank ' ""
oi.rcuita for each band can be 'tlsed, but ,i
W4TKR simplyswltches trinmer capacl'fcors "/
with a single coil as shown. This
requires-fcha-b.LI 01 tune to 24. 5 Me. with
a low value .. 6f^ C at 01 in order to
achieve a reas'-oriabl'e L/G ratio a-fc 10*5 J,
Mc . ^ e value or-' :C4 . s haul d be adjus te d /7-T
'fco give 'the deslreS coupling to-the
mixer*
All for this month,
75
.
ff. E. MILLIN Hon. See Taa. Mv