The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1924-11-28

| four inches for the length, and the SIX
inches as the circumference Clean
the brass where the ends meet and
with little solder and some paste,
solder them together.
You will then find that this circu'
lar form will fit very snugly inside OF
the coil which you prepared but few
minutes ago. Then take a piece OF
brass and use 1t as a crosspiece SO
that there will be some place for
wooden rod to control the movement
of this metal cylinder. A piece OF
dowel pin one-quarter of an inch In
diameter will serve as the shaft fol
! the cylinder.
We've got to mark the panel out
so that there will be a uniform. well.
balanced, panel layout. When doing
this, you will find it best to mount the
coil at the right center of the panel
so that the shaft will project at dead
center. Then mount the rheostat
bit below center-and toward the right.
The peep holes for the tube should be
marked out above center and in line
with the shaft for the rheostat.
Drill the panel carefully, feeling
your way, so that you will not burr
the panel when the drill goes through.
The best way TO avoid this is to ap-
ply little pressure on the drill, and
turn 1t in steady fashion.
Mount the coil to- the panel with
two angle brasses, and fix theNrod SO
that it passes through the panel
] smoothly. Tighten the four-inch dial
! on the rod so that by pushing it in
and out you will be able to control
the position of the metal cylinder.
Wiring the Set.
The next step would be to mount
the rheostat, binding posts and the
Dashboard, upon which should be
mounted the socket.
Now that everything is mounted. we
may proceed with the wiring of the
receiver.
Solder a piece of bus bar to the
antenna post on the set and run it to
the beginning of the fifteen turns.
Next continue this connection to the
plate of the vacuum tube socket. Con-
meet wire from the plate of the sock
ct to the phone binding post as shown
in Figure 1. The end of the fifteen
turns is connected to the ground bind
| ing post and to one side of a .001
fixed Dubilier condenser Connect the
other side of the condenser to the
| filament minus. Run wire from the
beginning of the 100 turns to one side
of the grid leak and condenser COM
bined. The other side of the grid con-
1 denser is connected directly In as
short and direct possible way to the
grid binding post on the socket.
Further Wiring.
Now we connect the end of the sec.
ondary Goo turn winding) TO the fila
ment plus. We have but few con-
nections TO go. They are: A wire from
the remaining phone post to the "B"
plus. a wire from the "B" minus to the
"a" plus The "a" minus binding
post goes to one side of the rheostat.
the remaining terminal of which goes
to one of the IF" posts ON the sock
: ct. A wire is then run from the other
'F'' post on the socket to the a.
battery plus.
Well, the wiring of the set is done.
1t might be wise to recheck your con-
nections, following either the schemat-
| ic diagram of Figure 2 or the picture
lookup of Figure 1.
/ Undoubtedly the set will work, but
the signals may be weak If this be
the case, the secondary leads are re-
versed. A sransposition of leads
should settle this trouble in a jiffy.
| If the set bursts into oscillation too
easily, try lower and higher values to
bypass condensers from the ground
| to the flament minus. (The higher
the value the more it will oscillate).
When the copper oil BRASS ring is
drawn inside the tube remember it Is
not connected in any electrical way),
| it concentrates the magnetic field of
the coil. When the ring is slid out
of the surrounding field of the coil.
| the distributed capacity of the induc-
lance is increased Consequently we
are able to tune the set merely by the
| relative position of brass ring. Ma
condensers of any kind are used, and
consequently the efficiency is kept near
the hundred mark. New York Tele-
gram.