The Washington herald., 1922-06-20
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terry in q detector set. no ampiin-
cation.
(b) Please tell me how to make
q ,vario-coupler and q variometsr.
(c) What size wire should each
be wound with? In No. ~ or, No.
2s too large for vario-coupier!
(d) Can a loop aerial be used
with q crystal detector set? win
II give as good results as an out
side aerial?
(e) Does the height OF an aerial
have anything to do with receiving
radio telephone messages?
| ~ Does length? That Is. 10 the
range or strength OF signals In
| creased?
tg) I have an aerial 13o feet
long 80 feet high at one end and
Is feet at the other end. Will 1t
increase the eficiency of the set II
add another wire7 1t is No. II
BIS copper single stranded. VIII II
',slp to make It higher or longer?
Some time ago asked for q
hook-up of a crystal detector set
and the one you sent worked fine.
R-v. s.
A. A potentiometer Is not neces-
sary.
(bD This involves too much dis
cussion. A diagram will be for
warded by mail. Tubes for the
vario-ooupier may be purchased at
a reasonable price and will be more
eficient for a home made set. On
the primary OF such a coupler.
which Is usually a 4-inch tube.
wind 40 turns of No. ~ covered
magnet wire and tap of each turn
for the FIRST ten. after which tap
of each ten turns. For the Sec
ondary use a 3-inch tube on an
axis which will permit the sec
ondary to turn completely around
inside the primary. Wind this with
No. 2s DISC wire for an inch and
a half
(c) No. "a primary and No. 2s
secondary will be satisfactory.
| (dD A loop aerial may be used II
properly connected to the set. but
In general II is very much less ef-
fcient than a straight aerial for .
crystal detector set. To work ef-
hciently a loop aerial should be at
tached to set employing one or
more stages OF application.
(e and ~ Inductance. capacity
and wave length are Influenced by
the height and length OF an aerial.
In general. long, high aerials are
more efficient. As to signal strength,
this Is controlled more particularly
in the secondary circuit.
tg) IL you have space available
and the wire on hand II will be
well to stretch another aerial wire.
For receiving. a single wire is all
that Is necessary. Raise the aerial
IL possible. this will increase the
length of lead-in. The lead-in acts
as vertical antenna wire.
Aerial Arrangement.
O. Please tell me which Is the
best plan for my aerial. have zoe
feet over all. Would two wires
feet apart, 20 feet high on a
four-story house be best. or one
wire!
(b) Would two wires make more
noise In the receivers than one
wire? Some say one wire is best
and some say two wires. I notice
most government plants have two
wires. A. n. ".
A Use two wires spaced 3 feet
a -
eps rms spacing VIII tend to
nu'ua'y ihouctiVe'
e"u'on oesneo.
| Condsnser Material.
@. Will the metal from a tin can
make a variable condenser?
(b) Is a horn gap lightning ar
4 rester very satisfactory for radio
use? c. c.
A. Yes. but ii Is not a good ma
terial' to use
(b) Horn gap arresters Of certain
makes are satisfactory. The Dis
trict radio inspector will give you
ms information. The National
,or 81. III, car
dI.,s,ss VIM s'~ho 'oo-'oit
Ihdoctanee-Honeyeomb Coils.
Q. Which in the hands of an ex-
perienced operator ar. the most 80.
fcient. honeycomb coils or the two.
variometer set?
(b) What size honeycomb coils
would be used to tune from 200 tc
5000 meters?
(c) What size honeycomb coils
are used in the so-caIled Universal
receivers. that tune from $50 to
$4,000 meters?
. A. You will find a variometer se,