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AMATEUR TRANSMITTERS.
The following is a complete list of
experimenters holding transmitting
licenses in Tasmania:
LAUNCESTON:
Mr. L. Crooks, 64 Frederick-
street .. .. .. .. .. .. .. .. .. 7 BQ
Mr. C. Scott, 14 Law-street .. .. 7CS
Mr. E. Sheldrick, Richards-
Avenue .. .. .. .. .. .. .. .. 7 BJ
Mr. A. Smith, High-street .. .. .. 7AB
Wills and Coy., Quadrant .. .. .. 7BN
HOBART:
Mr. T. Watkins, Warwick-
street .. .. .. .. .. .. .. .. .. 7 AA
Mr. R. O'May, Bellerive .. .. .. .. 7OM
Mr. J. Brooks, Adelaide-street .. 7JB
Mr. R. Buring, Davey-street .. .. 7AX
QUEENSTOWN:
Mr. Preston .. .. .. .. .. .. .. .. 7BK
STATIONS HEARD.
The following is a list of stations
heard on a low loss receiver by Mr.
C. Scott of 14 Law-street, Launceston
from 15th to the 18th instant inclu-
sive on about 80 to 90 metres:
N.S.W.: 2YI, 2AY, 2AW, 2DS,
2BX, 2BV, 2GM, 2NI, 2IJ, 2SP, 2
CM ('phone and CW), 2BK. Vic-
toria: 3LM, 3BD, 3EM, 3XF, 3
TM, 3YX, 3AP, 3EF, 3HH, 3CB,
3EL. South Australia: 5AH, 5JC,
5RM, 5BG, 5BN. New Zealand:
4AA, 1AO. Unknown: NEA.
RADIO CLUBS.
The Hobart "News" says that seve-
ral correspondents have written to
that paper asking for particulars and
dates of meetings of the Hobart Ra-
dio Experimenters' Club, which was
formed some months ago. Unfortun-
ately, "Ampley" (the writer of the
wireless notes in the "News") says he
has been unable to supply me infor-
mation, owing to the rather negative
condition of the club at present.
The last meeting was held several
weeks ago, and the attendance was
anything but good. Interest in the
club's doings appears to be waning,
more particularly on the part of the
members of the club themselves.
It has been suggested that the Ho-
bart club should follow the example
of the Northern body, "The Launces-
ton Radio Experimenters' Club,"
which has been holding meetings once
a week. The Launceston club, it Is
pointed out, is doing its best to pro-
mote a more general interest in wire-
less in the North, an indication of
this being the recent successful exper-
iments carried out in connection with
the Henley regatta, when the results
of races were made known to thou-
sands of regatta visitors by means of
loudspeakers installed on the ground.
One correspondent expresses the
opinion that the local club should not
only cater for the interests of the
experimenter but the broadcast liste-
ner as well, the latter now being by
far in the majority. The correspon-
dent further suggests that technical
lectures should be given at each meet-
ing concerning the control of various
types of wireless sets. "These lec-
tures," he says, "would prove invalu-
able to the novice, who is now faced
with the difficulty of finding out his
troubles without assistance."
T AERIALS.
When using an aerial of the T type
care must be taken to connect the
down lead as near to the centre of
the horizontal span as possible, other-
wise the currents taken by the set
will, not be in phase, one leg of the
arial having a slightly different L.C.
value from the other. The net re-
sult will be a loss in signal strength.
In such circumstances it is better to
change the down lead to one end, thus
converting the aerial to the inverted
L type. The difference in directional
effect is practically negligible on
broadcast reception.
Phonetic Alphabet as Generally
Used for Wireless Telephony Call
Signs Throughout Australia and
Tasmania:
A — Ack.
B — Beer.
C — Charlie.
D — Don.
E — Edward.
F — Freddie.
G — George.
H — Harry.
l — Ink.
J — Johnnie.
K— King.
L — Loonie.
M — Monkey.
N — Nuts.
O — Orange.
P — Pip.
Q — Queenie.
R — Robert.
S — Sugar.
T— Toc.
U — Uncle.
V — Vic.
W — William.
X — X-Ray.
Y — York or Yorker.
Z — Zebra.
Example: 7 Beer Johnnie calling
7BJ.
WIRING YOUR SET.
'When, wiring a set .it is 8- good
plan to begin with the grid circuits
then go on with the. anode circuits,
and' finally 'complete the filaruenL or
--t earthed circuits. In this way the
high-potential leads can be made as
snort and direct as possible, and the
set will give the best results.
'PHONE HINTS.
11' 'phones are to Rive tho best ser
vice they must be treated with some
care and attention. They should
not be laid on the bench with a thud,
for the blow may affect the sensitive
nes:-. of the permanent magnets.
Usually phones should not tie coupled
to a set powerful enough to work a
loiid speaker, as the windings may be
damaged by the heavy current. For
tuniug-in the phones should be placed
in the anode circuit of the detecting
valve. -
CABINET INSULATION.
Wood is ?often a sufficiently good
insulator for mounting compnenets
that are to' 'be used for experimental
purposes only. When thus used the
wood Should. 'be quite dry, find may
with advantage be given a coating of
shellac varnish. In such a oase it is
desirable that the wood on T-vhich the
apparatus is mounted is insulated for
earth. - Tliis can be easily accom
plished by ftxing under each corner of
the basebord a small rubber heel.
DEFECTIVE CONDENSERS.
Variable air-condeusers frequently
get out of 'adjustment and give rise
to a^ good deal of trouble, in particu:
lar, the plates -ire apt to .touch one
another, so producing some sort of
electrical leakage, if not an actual
short circuit. If there is real con
m ? m
A chart shoyving how Marconi's beam reached Australia when the first successful tests were made. m — : — _u ? — a Help
A chart shoyving how Marconi's
beam reached Australia when the
first successful tests were made.
m — : — _u ? — a
tact between plates, this will usually
be so obvious, either by the scraping
when the condenser is turned, or by
variations or disappearance of the re
production in the 'phones, that there,
will i he no difficulty in diagnosing the
trouble. But one test which may be
applied easily is this. Disconnect the
condenser entirely from the set, then
connect an ordinary flashlamp in
series -with a 2-volt cell and with the
condenser. Turn the condenser knob
completely round and watch if there
is any lighting of the lamp. A short
rircbtt VWsGon be discovered in this
way.
A SIMPLE TEST.
But more, usually the trouble is not
so serious, and in most cases it
amounts to a leak rather than to a
short circuit. Perhaps hairs or dust
have accumulated on the plates and
formed a high resistance connection
charge up the condenser by momen
tarily connecting its terminals to the
full voltage of the H.T. battery (tak
ing *;are not to touch the terminals of
the condenser with the fingers); then
leave it for, say, five seconds, and
then touch the two 'phone tips against
the condenser terminals. If the con
denser ha6 notj lost its charge a click
will be .heard in the 'phones. Try
this experiment several times, leaving
the condenser, say, 1 second, then 2
seconds, then 10 seconds, and so on.
If there is a considerable difference
between the effects obtained at 1
second and 10 seconds, it shows that
, the condenser is leaking. It should
then be carefully cleaned out be
tween the plates.
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