Vhf Packet (F2 Mode) Operation - Yaesu FT-767GX Operating Manual

( F2
VHF
4 . 1 7 Packet
The FT-767GX o ffers specia l features for pac­
k e t r a d i o o p e r a t i o n on V H F o r U H F , u s i n g t h e
F M m ode o f emission.
e v e r , t h e A F SK s i g n a l l e ve l s p r o v i d e d by y o u r
t nc ( t e r m i n a l n o d e c o n t ro l l e r )
s i o n , a s w e l l a s t h e s i g n a l l e v e l s r e q u i r e d b y
t h e t n c f o r r e c e p t i o n .
I f y o u r t nc h a s b a l an c e d A F SK t o n e o u t p u t
( that i s , w i thout any added de - e m phasis ) ,
nect the AFSK signal from your terminal node
c o n t r o l l e r t o t h e o u t e r c o n t a c t of t h e DAT A
IN/OUT j ack : i m pedance should be
which corresponds with most t ncs.
n a l l e v e l f r o m t h e
30mV r m s.
I f y o u r t nc h a s d e - e m p h a s i s a p p l i e d t o t h e
A F SK o u t p u t, t h e l e v e l s o f t h e t w o t o n e s w i l l
b e d i f fe r e n t , a n d m u s t b e r e - b a l a n c e d b y p r e ­
e m p h a s i s i n t h e FT -767 GX.
c a n c o n n ec t t h e A F SK s i g n a l from the tnc for
t r ans m ission to the PAT C H IN j ack ( also 600 -
o h m i m p e d a n c e ) , b u t y o u m u s t a l so a d j u s t t h e
t n c o u t p u t l e v e l f o r 2 m V r m s m ax i m u m .
P AT C H IN au d i o c o n n e c t s in p a r a l l e l w i t h the
m i c r o p h o n e au d i o i n p u t .
t o r e m o v e t h e de - e m p h a s i s ,
m ake connec tion a s described i n the preceeding
p a r a g r a p h .
F o r r e c e i v i ng, t h e r e a r e a l s o t w o a v a i l ab l e
output poin t s for FSK, again dependi ng on whe­
t h e r y o u r tnc p r e - e m p h a s i z e s r e c e i v e a u d i o .
I f t h e t nc c a n a c c e p t
( su c h a s t h e G L B P K T - I ) , c o n n e c t t h e c e n t e r
con t act o f t he DATA IN/OUT j ack to t h e recei ­
v i n g i n p u t on t h e t n c : o u t p u t l e v e l i s 800m V
at 10 k i l o h m s, so m ake sure your t nc can han­
d l e t h i s h i g h l e v e l ( o r add a l Ok r e s i s t o r to
g r o u n d a n d a n o t h e r
l e v e l ) .
I f y o u r t n c r e q u i r e s u n b a l a n c e d t o n e s
i n c l u d e s i t s o w n p r e - e m p h a s i s ,
TAP R TNC - 2 a n d c l o n e s ) , u s e e i t h e r t h e l ow ­
l evel signa l at the AF OUT j ack ( l OO mV a t 10
ki l oh m s ) , o r t h e h ig h l ev e l s i g n a l a t t h e E X T
S P or PHONES j ack.
Note, however, that using the EXT S P o r PHONES
j a ck h as t w o s e r i ou s d i s a d v a n t a g e s :
g i n g i n t o t h e s e j a c k s
s p e ak e r , m ak i ng i t i m p o s s i b l e t o m o n i t o r t h e
r e c e i v e r ( t his i s n o t r e c o m m e n d e d ) ;
t h e A F g a i n a n d TONE c o n t r o l
a f fe c t t h e p a ck e t i n p u t t o t h e t n c.
mode ) Operation
You must det e r m i ne, how­
f o r t r a n s m i s ­
con­
600 ohms,
Output sig­
t n c s h o u l d be s e t
I n t h i s c a s e you
The
A b e t t e r s o l u t i o n is
if p o s s i b l e ,
b a l a n c e d t o n e l e v e l s
i n s e r i e s t o s e t
( a n d
s u c h a s t h e
( 1 ) p l ug ­
d i s a b l e s t h e l o u d ­
a n d ( 2 ) ,
s e t t i ng w i l l
Tlie low -level s ignal a t the AF OUT j ack i s the
b e s t c h o i c e , as the r e c e i v e r AF p o w e r .a m p l i ­
f i e r i s b y p a s sed.
r e c e i v e r i n p u t f o r h i g h l e v e l s p e a k e r a u d i o ,
you m i gh t wish to bypass t h a t attenuation,
then use the AF OUT j ack.
Set the FT -767GX to the FM m ode for V H F and
UHF packet ( to be compatible with most other
o p e r a t o r s us i n g 1200 b i t s/ s e c o n t h e s e b a n d s ) ,
and s e t t h e MON I , APF and NOT C H switches OFF
( ou t ) . Also,
o r F T S - 8 T o n e S q u e l ch U n i t i n s t a l l e d,
sure the T EN C swi tch is OFF ( ou t ) and the S QL
c o n t r o l i s n o t i n t h e T S Q L p o si t i o n .
t o v e r t u n i n g is
Use the m e m o ries to store the com m on p acket
c h a n n e l s in y o u r a r e a , f o r e a sy r e c a l l.
a n d
t h e
33 -
I f y o u r t n c a t t e n u a t e s t h e
if you have the FTE - 2 Burst Unit
as d e s c r i b e d f o r F M ( § 4 . 16 ) .
and
m ake
R ec e i ­