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ANSWERS TO INQUIRIES.
'Ptnried,' EMt P«rth widiM in kaow b«w
t-o «T«r«rale the reMpint noitsmsd* br tha
e«-UDens«r -J5*1 rnbbin* »t&in tbe p«nel.
of thin feW «bosld b« r'n«»4 -« th* under
neath aide of the rim of -the difcl. It
would) be advisable, howerer, to first cine
a thin ring of c*rdbo»r4 on tbe dial lrhich
will give a betttr 'grip' to the felt. The
felt may bo either flush with the Tim of
the dial or projecting slightly. 'When this
is d%n« the dial mar *-« -*t Atntn flrmly
against the panel, and it wHl not be very
tout before the condenser trill hare ac
quired a till? feeJln* rouudi -the wbolie of
dU scale.
'Battery,' Perth, writer— A friend «f
Brio* sufgaisK the inclusion of » grid bat
tery in niy low-frequency antpUfler, and I
would like to know if this would be «n im
provement.
Answer: Host -toeife-Hy. It set only im
prors* the quality of reproilTietton. when a
high value of H.T. is used, bat H Also cntt
down the pl*te current, and, therefore,
lengthens the life of the high-tension batter;
'D.V.,' Perth is constructing a portable
receiver, and wUhes to know if insulated
wire ?hqaldi be used for tbe wiring.
Anmrer: No. Only the 'A' and 'B'
battery connections should be of insnlMed
wire. This is done to prevent any possi&fo
cbort circuit, and where there is plenty of
room ttttweon the battery wires, bare wire
maj be ns«d. Coonectioa to the compoorot
pmrte of coca a receiver should be *s short
and (Krart a» possible, taking care that the
respective wjr« of tbe circnH are far enongrh
away from each other to prevent jarring
from oaoainc a gbort circuit.
'Ignorant Beginner,' Fremantle «»k» th»
following qnettitms: — (1) I am building a
cryattf tet and would be pleamd if yru
could sapptf me with the tttme of some aab
itance to paint th« wooden part of tb» set;
(2) What is t«me* 'Iwavy gauge' wire.
(3) What range aerial wire is needed to
Tsceivo '«WP.' (4) What height ind
length is it nscaanry to have the aerial,
(S) Wbt dues the abbreviation 'mfd'
mean.
Answer: (1) Sh*lloc, applied with ? clean
raf. Three ooata riionld give the wood
work a hlrhly poltohedi finish (2) No*. 13,
14, 1-6 kbA 1.8, 8.W.O. are termed 'heavy
Ciuce' wire. (3) No. 18 gauge or 7/22
stnadM copper wrne I* the bast to im
for Mniftla. (4) To receiva 'ftWF' the
aerial tnauld be about 100ft. lone and 38ft.
high. (8) 'Mfd' means mierotand, wWeh
if ?«?* t» mMtOioatt yut U » «M»d,
whjcb, is a unit of electric capacity. The
abbreviation mid is applied to doadensers,
both fixed and variable-, and represents their
, cawcitiM And capability of storing elec
tricity
'H.S.,' Inglewjodi, would' like- to know
how to prevent noi&ee of a high-pitched tone
wfiich: occub in his ett whenover. anyone
' moves about tlw xoom * in which the set is
installed.. :
Answer^: The sounds mentioned; are pro
bably mi'crophonic noises,, and which are
cihised by the-. plat» and fibmeot of the
valves vibrating' when they' nave been jarred.
Mounting the sockets for the valves on rub
ber, and making connections to the valves
with flcifble wire will materially reduce
the noises-.
'PJi.,' Osborne Park hais a three-valve
set, but is at a loss to find a food earth
connection. He states that the eairtn in the
vicinity of the house is all eand, and would
tike to know if that has anything to do
with the connection.
Answer: Sandy soil offers & high resis
tance to the passage of an electrical current
and for this reason it is difficult to obtain
a good connection, to the earth. The best
remedy is to nse a counterpoise. This is
nothing more than a number of -wires sus
pended directly under the receiving aerial
It ebonld consist of at least as many wires
as used in the aerial, and may h4 supported
?from five to twenty feet above 'the earth.
"Condenser," Darlington, would like to
receive information regarding the follow-
ing:— (1) Would it be possible to tune be-
low 80 metres with a .0003 mfd variable con-
denser, using coils of 2 and 4 turns, each
of copper wire, 3/16 of an inch in diameter.
The natural wave-length of the aerial, in-
cluding lead-in, is about 230 metres. (2)
Would the aerial do or should it be shorten-
ed to receive local amateurs. (3) What
wave-lengths do they work on, also their
times of transmitting. (4) Would an aerial
100ft. long and 30ft. high be suitable for
receiving Eastern States' broadcasting.
Answer: (1) For receiving on short wave-
lengths, i.e., up to 80 metres, the aerial
should not be more than 50ft. long. The
.0003 mfd condenser would be O.K., but
the coils would not suit. You do not state
their diameter, but would advise 8 turns of
No. 18 d.c.c. wire for aerial and 12 turns
of No. 16 for the secondary (2) Answered
by No. 1. (3) 6AG, W. E. Coxon, 30 and
90 metres, 6BN, A. E. Stevens, 90 metres;
6BO, A. E. Gray, 70 metres; 6AM, F.
Kennedy, 85 metres; 6WP, W. Phipps, 70
metres; 6CJ, E. J. Darley, 75 metres; and
6AB, O. Cecil, 90 metres. These wave-
lengths may vary, as these transmitters are
continually experimenting. (4) Yes.
'G/S.,' Swanbounre, states that he. has
noticed lately that when the wind! blows
tatremeily hard a,' rough scraping noise is
Beard ia tbe art. The aerial U ? single
^re, 75ft. lon«, -with ? lead-in' from near
the centre. Would this 'be the cause of
the noise.
Answer: It is ..possible that the tad-fat
wire i» making .poor contact, ,«nd tbe -Wowini
of tbe wind causes, it to make and1 break
connection with the horizontal wire. If thii
wire is not soldered it should be. In any
case it should be carefully examined, and if
there is- the slightest doubt, reaolder it to
taake sure of a positive 'contact, for in all
probability tils' ir wher» the -trouble lies.
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