New-York tribune., 1922-03-12

would not answer the same purpose
One coil can be used for both primary
and secondary, provided that suitable
"sliders' are used for the primary and
secondary circuits.
How to Shield Set
S. c. w, DiXondale, Va:
Q.-How do you shield a panel, how
much and what thickness of mate rial
do you use? Aft you take very thin
sheet copper and carefully fit it to
your panel, making holes large enough
for the various wires and binding
posts to pass through without touch
ing, and then solder this shield to
your ground connection, you will have
completely shielded the receiving set.
Tack the sheet copper to the cabinet
with very fine small nails If the cop
per is not available you can use foil,
provided, of course, that the foil does
not touch any connection other than
the ground connection.
Q-1n viking up a set of instru
ments what number wire had / better
use; is oiled cambric or other tubing
necessary? A.-You can use No. 1S
bare copper, soldering all connections.
and covering the copper with "spa-
ghetti' tubing. or oiled cambric.
Q.-Would you use a variable con-
denser in connection with vario-
coupler. if so where in the circuit?
Alt will be necessary for you to use
variable condenser across the sec
ondary of the vario-coupler, 1t should
be approximately .OO1 mid capacity.
Q-Would you use, CIR is it necessary
to use, variometer on both plate
and grid when using a vario-coupler
with ticker coil? A.-You must use
circuit consisting Of vario-coupler
and ticker coil, or else circuit con-
sisting of vario-coupler and plate ana
grid variometers. You cannot use b tn
together. You can make two such
circuits and arrange to make the neces-
sary changes by means of "throw over"
switches, but both circuits can't be
used together.
Q.-I do not find ticker coils listed
in any catalogue, what are they? Al
The ticker coil is variable induc-
tance that is placed in inductive rela-
tionship with the secondary Of your
vario-coupler. 1t gives the regenerative
effect to your circuit in connection
with the vacuum tube detector.
The Vernier Adjustment
Q.-What is meant by vernier adjust
ment and what is its value? A.-The
vernier adjustment is the fractional
adjustment of getting the circuit tuned
as exactly as possible to the transmit
ting station. You can attach vernier
adjustment to your set by shunting
three plate condenser across the sec
ondary condenser already mentioned
above.
Q.-Can filament jacks be used in
place Of rheostats? 1t is advisable? A.
-Filament jacks can be used so that
the bulb not in use is not lighted, but
you will still need rheostat to get the
right value of current in the filament.
Q.-Can one jack and rotary cam
switch be used in place of two or three
jacks in detector and two-step ampli-
fer set? A.-You might be able to de-
wise some scheme with cam switch
whereby it would take the place of two
or three jacks, but I doubt whether it
would be as efficient as the jacks them
selves.
Spider Webs for Long Waves
Q-Will spider-web coils take the
place of transformer or vario-coupler?
What is their value and use? A
Spider-web coils can be used in the
same manner as honeycomb coils, but
they are more suitable for long wave
reception.
Q-Can one flament rheostat be
used on the two flaments of two
Help You Solue
D-J. D--l1o~n