Yaesu FT-767GX, Operating Manual

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I f backgrou n d nois e is s t ro ng enough to c a u s e
the S - m e t e r t o d e f l e c t above S - 3, swi t c h o f f
the R f AMP.
I f the S - meter still deflects on
the noise, and if more t h a n S - 3, t u r n t h e
ATTenuator on.
I f the S - m e t e r de f l e c t s, but to l es s t h an S - 3,
turn the R f gai n co n t ro l cou n t e r c lo ckwise
gradu a l l y u n ti l t h e S - m e t e r just b egin s to
rise, and then d ro p t h e R f g ain b ac k a lit t l e
to the t h r e s ho l d poi n t.
You r receiver is now
set fo r m axi m u m u s e f u l sensi tivi t y o n t h a t
b a n d ( t he s e t tings a r e di f fe r e n t a t di f fe r e n t
ti m es, on di f fe r e n t b a nds, and wi t h di f f e r e n t
a n t e n n a s a n d s t a tion loc a tio n s ) .
O n the o t h e r h and, i f t h e b a c kgro u n d nois e
causes no S - m e t e r de f l e c tion, you m ay n e e d
more receiver gain : switch off the ATTenuator
if it is on, and i f s ti l l no S - m e t e r d e f l e c ­
tion, switch o n the Rf AMP ( they should never
bo t h be on toge t h e r ) . A s soon a s you s e e a
li t t l e S - m e t e r d e f l ection, a d j u s t t h e R f g ai n
as j u s t des c ribed.
No te: Remember: there is no advantage to
s e t ti ng r e c eiver gain higher t h a n w h a t is
n e c e s s a ry to receive sig n a l s above the
background noise.
The S - meter can be set
to read higher o n sig n a l s and nois e, b u t
this usua l l y c a u s e s t h e receiver t o b e
mo re s u s c e p ti b l e to dis to r tio n fro m s t ro ng
sig n a l s, d e c r e a si ng o v e r a l l r e c e p t io n
q u a li t y. fo r b e s t r e c e p tio n q u a li t y, a l ­
ways use the minimum sensitivity needed.
4. 1 3. 2 S t rong S i gnal S S B Reception
fo r s t rong sig n a l recep tio n, fo l lo w t h e s a m e
steps as above.
Set the AG C to slow, and turn
the Rf gai n b a ck as m uch as po ssi b l e so t h a t
you c a n s ti l l h e a r t h e inco ming sig n a l duri ng
any fading t hat m ay occur. When the receiver
is s e t p ro p e r l y, sig n a l - t o - noi s e q u a li t y
should be almost as good as FM.
4. 1 3. 3 Suppressin g Man - m ade I nterference
I f u n w a n t e d s t a tion s are heard n e a r the s igna l
you are lis t e ni ng to, f i r s t m ake sure you h a v e
your station tuned in precisely ( press C L AR i f
you r e t u n e duri ng a Q S O ) , and then p re s s
D
LOCK to disable the tuning knob. Now try ro­
t a ting t h e S H I FT con t ro l slig h t l y. No t i c e
t h a t t h e pi tch o f t h e sig n a l s wi l l shift, a n d
you m ay b e ab l e t o reduce the i n t e r f e r e n c e
whi l e s ti l l co pyi ng. The TO N E con t ro l c a n b e
h e l p f u l in co r r e c ti ng fo r t h e a l tered p i t c h
caused by S H I FT adjustment.
I f t h e S H I FT a dj u s t m en t does no t h e l p, t h e
i n t e r ference m ig h t no t be d u e t o n e a r b y sig ­
n a l s, b u t to i n t e r m o d u l a tio n f ro m s t ro ng
sig n a l s on far f r e q u encies.
I f t h e s t a tio n
you are lis t e ni ng to is s t ro ng enough, t u r n
o f f t h e R f A M P, t u r n on t h e ATTen u a to r, a n d
reduce the R f g ai n, o n e a t a tim e i n t h a t
order, s to p ping w h i l e t h e desired s t a t io n i s
s ti l l r e a d a b l e.
Make c e r t ain to re - c e n t e r the S H I FT co n t ro l
before you turn the
D LO CK off and retune.
fo r h e t e rodyne i n t e r ference such as fro m A M
s t a tio ns, o r fo r m any t ypes o f ' b uz zing ' sig ­
nals such as those used for jam ming on the Hf
bands, the NOT C H filter can be helpful.
Press
D LO CK to dis ab l e t h e tuning k nob, an d t h e n
t u r n on t h e NOT C H fi l t er a n d adj u s t i t v e r y
gradu a l l y fo r a dip i n t h e i n t e r f e rence ( show n
on the S - meter ) .
Remember to turn t h e NOT C H filter o f f before
turning the D LO CK off and retuning.
4. 1 3. 4 M i s c e l l an e a
Use c a r e w h e n t u ni ng i n a n S S B signa l, a n d
then press D LO CK so you can m ake fine adjust ­
m e n t s to t h e I f p a ssband a n d au dio wit ho u t
havi ng t h e m s u d de n l y u p s e t by an acci de n t a l
bump of the tuning knob. Use the memories for
n e t or schedu l e f r e q u e ncies.
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