Antenna Alignment - Elenco Electronics AM/FM-108TK Manual

ANTENNA ALIGNMENT
Tune the radio for a station around 60OkHz. With
the
"magic wand" place
the brass end near the antenna coil
as shown in
Figure 23.
lt
the signal heard at the output
increases, it
means that
the
antenna coil needs
less
inductance. To remove inductance, carefully slide
the
antenna coil along
it,s
ferrite core in the direciion shown
in
Figure
23.
place the iron end of the
,,magic
wand,,
near the antenna coil.
lf the signal heard at
t-he
output
increases, this means that the antenna
coil needs more
inductance.
To add more inductance, carefully slide the
antenna coil arong its ferrite
core
in the direction shown
in Figure
23.
Repeat
these steps until the signal heard
decreases for both ends of
the;,magic wand,,.
Tune
the
radio for a
station around
14OOkHz.
With the
,,magic
wand", place
the brass end near the antenna coil.
lf the
signal heard at the output increases, it means that the
antenna
coil
needs more capacitance. Adjust
the
antenna
trimmer
on the back of the gang
untilthe signal
is at its loudest.
Refer to
Figure 25
tor
the location
of
the antenna trimmer. place the iron end of the
,,magic
wand"
near the antenna
coil.
lf the signal heard at ihe
output increases, it means that the antenna coil needs
less capacitance. Adjust the antenna trimmer on
the
back
of the
gang until
the
signal
is at its
loudest.
Repeat these
steps untilthe signal heard decreases for
both ends of the "magic
wand',. Since the adjustment of
both the antenna trimmer and antenna coil will effect
the. antenna alignment, it
is
advisable
to
repeat
the
entire
procedure
until the
antenna alignment
is
optimized. This
process sets
the
tracking
of the
AM
radio section.
Once
the
antenna is
property aligned,
CAREFULLY
Apply
CANDLE WAX or
glue to
thr
antenna coil and the ferrite rod
to
prevent
it
fron
moving
(see Figure 23A).
This concludes the alignment of the AM radio
section
lf
no stations are heard, verify that AM signals
are
present in your location by listening to another
AM radic
placed near the
superhet 1oBT.
rf
the AM section
is
stirl
not
receiving,
go
back and check each stage
for
incorrect values and for poor
soldering.
proceed to the
FM assembly section.
.
More inductance, slide
the
coil
__+
.
Less inductance, slide the coil
+_
Figure
22
AM
ALIGNMENTWITHTEM
IF ALIGNMENT
Connect your RF generator and oscilloscope as shown
in
Figure
24.
Make sure that the switch
is in the
AM
position.
Place a
short from the collector of
e7
to Tp6.
This short "kiils" the AM
osciltator.
Figure
24
Oscilloscope
caoug
.,1
I* c
.001ptF
Short TP6 to the collector
e7.
Hl'
=k
(-,ru
TP1 5
,{J-Jl-\
Kt9
TP15