The West Virginian. [volume] (Fairmont, W. Va.) 1914-1974, 1922-04-28

se~e-~-ses~4-@e~.---~-~4
phone receivers to the binding
posts,
Loosen the set screw. Of the crys.
taal detector binding. post slightly
and change the position OF the fine
wire to several positions Of CON
tact with the crystal until the
loudest sound is heard In the
phone. Then slightly tighten the
binding post set screw.
Accessories
Under the heading OF accessory
equipment may be listed binding
posts; switch arms, swith con.
tracts. test-buzzers, dry battery
and boards on which TO mount the
complete apparatus.
The binding posts, switch arms
and switch contacts may be pur.
chased from dealers who handle
such goods or they may be readily
improvised at home. The pieces o.
wood OF which the equipment Is
mounted may be obtained from 8
dry packing box and covered with
paraffln to keep out moisture.
Care should be taken in melting
the paraffih MOTTO get It too hot,
For this reason tits a good plan tc
melt It in a pan set in, boiling
water When the paraffin just be,
gins to smoke 1t Is at the proper
temperature.
When the wood parts have beer
drilled and cut to size, the paraf,
fin should be applied quickly Will
a small brush. When cold, the ex,
cess paraffin must be carefully
scraped off with a straight piect
OF metal such as the brass strip II
the edge OF a ruler.
y Construction
Following is a description Of the
method OF winding the tuning coli
and the construction Of the woot
panels:
TUNING co1L-(see Figure 81
The cardboard Tubing is 4
inches in diameter by 4 1-2 inche.
long. One end OF the tube should
have the cardboard cover glued
securely to 1t. About 2 ounces o.
No. "a Tor No. 26) double cotton,
covered copper wire Is used FOL
winding the coil.
Punch two holes in the tube
about ~ inch from one end
Weave the wire through these
holes in such a way that the emf
OF the wire will be firmly anchor
ed, leaving about IL inches OF tn,
wire free for connecting.
Start with the remainder OF thC
wire to wind the turns In a singh
layer about the tube, tightly ant
closely together. After 10 complete
turns have been wound on thu
tube hold these turns tight auG
take off a tap. This tap is made
by twisting a 6-inch loop OF tht
wire together at such a place tina
It will be slightly staggered from
the first connection. This methot
OF taking off taps is shown c!aarl,
IN Figure 8.
Proceed IN this maRner until
twisted taps have been taken Off
one at every 10 turns. After thest
Nflrst 10 turns have been wound OF
the tube. take off a 6 inch twisted
tap for every succeeding single
turn until 10 additional turns hayl
been wound on the tuba. ,Aftel
winding the last turn Of wire
anchor the end by weaving i
through two holes punched in the
tube as at the start. leaving abou
IL inches OF wire free for connect
ing.
1t Is to be understood that eacl
Of the IS taps is slightly staggered
from one just above. SO that the
taps will not be punched along on
line on the cardboard tube.
1t might be advisable, after
winding the tuning coil to DIP. tht
tuner in hot paraffin. This will
help to exclude moisture. It Is I'm,
portant to have the parattin neat
ed until It Just begins to smoke. a
previously explained, so that whel
the tuner Is removed 1t will have
only a very thin coat OF pararlin.