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1 MODEL 4OO TRANSCEIVER
C. Operation (Cont)
( i )
R o t a t e P A L o a d C o a r s e t o
p o s i t i o n 6 .
( j ) R o t a t e B a n d s w i t c h o n F r e -
quency Control Unit to
d e s i r e d b a n d ,
(k) Set !'requency
Control
Unit
tuning dial to desired operat-
ing f!equency.
( l ) S e t R ! . G a i n C o n t l o l t o
approximately
3 o'clock
p o s i t i o n .
3.
Rotate the Function
Switch clock-
wise to the REC position.
4.
Care{ully
adju6t the PA Glid
and
t h € P A P l a t e c o n t r o l s f o r m a x i -
rnudr receive!
noi3e.
Note:
The
PA Grid Control
resonates the
transmitter
driver
stages and the
receive!
RF amplifie!
plate cilcuit.
The PA Plate ard PA Load con-
trols
adjust the input and output
capacitors
in the transmitter
power
arnplifier
final plate circuit,
as
well as the receiver
RF ahplilier
g r i d c i r c u i t .
P r o p e r a d j u 6 t m e n t
o f t h e s e c o n t r o l s i n t h e r e c e i v e
position will
re6ult in approximately
resonant conditions
in the trans-
rnitter
stage6.
RECEIVER
TUNING
- IMPORTANT,
READ CAREFULLY.
Precise
tuning of a Bingle Bideband
signal is very important.
Do not be
€ a t i s f i e d t o m e r e l y t u n e u n t i . l t h e v o i c e
can be understood,
but take the extra
care of settiDg the dial to the exact
€pot where the voice sounds natural.
Above all,
avoid the habit of tuning so
that the voice is pitched higher than
norrnal.
This is an untortunate
habit
practiced
by quite a nuhber
ot oPera-
tois,
The following
points help to
explain the effects o{ rnistuning:
I.
If you tune so the received
voice 1s
higher than normal
pitch,
you will
then transmit
ofI frequency,
and
your Yirce will
sound lower
than
nor't[.]
pitch
to the other
station,
He wlll
probably
retune hi8 dial to
mak€ /,rrr sound right.
If fou keep
this up, you'Il
gladoally
waltz one
another across the band,
If both
of you are rnistuning
to an unnatural
higher
pitch,
your11 waltz across
the
band twice as fast.
(And someone
will
no doubt be accused of fre-
quency drift),
2 .
M i s t u n i o g ! e s u l t € i n s e r i o u s h a r -
. monic distortion
on the voice,
and
ghould be quite noticeable
to the
average ear.
Some will
claim
that
if they donrt know how the other
personrs voice actually
sounds, they
canrt tune hiln in propelly,
but this
i6 not true.
With a little
practice,
it wiU be Iailly
easy to tell.
Sorne
voices are relatively
rich in ha.-
monics,
and ale easier to tune iD
r h a n a p e r s o n v , / i t h a r ' I l a t " v o i c e .
AIso,
a transmitter
\rhich is being
o p e r a t e d p r o p e r l y w i t h l o w d i B t o r -
tion will
be eaEier to tune in than
one which i€ being over-driven
and
i s g e n e r a t i n g e x c e s s i v e d i s t o r t i o n ,
There is no lnistaking
when you
have a station tuned right on the
nose,
It wil.l sound ju6t like I'AM, r'
so to speak.
Mainly,
avoid the
habit of tuning 6o everyone
sounds
higher than rormal
pitch,
or like
D o n a l d D u c k .
T h i s i 6 i n c o r r e c t ,
unneceaaary
and sounds terrible.
3 .
A v e r n i e r
c o n t r o l f o r r e c e i v e f r e -
quency,
sometime6
reterred
to as
!'incremental
tuning,rt is not avail-
able on the S\ran 400.
Such a device
is not necessary
if proper
tuning
h a b i t s a r e e x e r c i s e d .
t 3
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