Active-Tuning Antenna System (Atas-100) Operation - Yaesu FT-847 Operating Manual

OPERATION
A
CTIVE
The optional ATAS-100 Active-Tuning Antenna System provides operation on the 7, 14, 21, 28, 50, 144, and 430
MHz bands.
Full instructions for its use are found in the documentation accompanying the ATAS-100.
To activate automatic tuning of the ATAS-100, Menu #31 must be changed from its default "TUNER " setting to
"ANT." See page 88 for details.
A T
UTOMATIC UNING
•
Press the [TUNER] switch momentarily to "turn
on" the ATAS-100. The "TUNER " icon will ap-
pear on the LCD.
‚
Now press and hold in the [TUNER] switch for ½
second to initiate the tuning procedure. The FT-
847 will automatically transmit a carrier, and you
will observe the ATAS-100 extending itself beyond
its fully-nested position. During tuning, the S-Meter
becomes a relative SWR indicator, and successful
matching will be indicated by a sudden "dip" in
the reading on the meter.
ƒ
When tuning is successfully completed, the FT-847
will return to the receive mode.
„
When changing bands, once a match has been ob-
‚
tained via step
[TUNER] switch for ½ second to initiate re-tuning
of the ATAS-100 for operation on the new band.
Although there is no "memory" of antenna posi-
tion, the ATAS-100 will raise or lower itself in the
"correct" direction if it has successfully achieved
an impedance match on one band.
...
For operation on 144 and 430 MHz, the loading
coil assembly must be fully "nested" at its mini-
mum length. If it is not in this position, touch the
[TUNER] switch momentarily; the ATAS-100 will
retract itself fully, and will turn itself off at the
nested position. Operation on the 144 MHz or 430
MHz bands may then commence.
62
-T A
UNING NTENNA
above, just press and hold in the
( ATAS-100 ) O
S
YSTEM
M T
ANUAL UNING
In some instances, the SWR may be slightly improved
by manual adjustment of the antenna position. This
may be needed for operation on bands like 17 meters,
where the "Q" of the ATAS-100 is high, causing a
narrow resonance range.
To tune the ATAS-100 manually, press the MOX
switch (or press and hold in the microphone PTT
switch). With the transceiver in the "T
press and hold in the [MH
tenna) or the [MH
While you hold in one of these keys, the FT-847 will
generate a carrier, and you may watch the top scale of
the FT-847's meter, looking for the meter indication
to reach its minimum value. When this is reached, re-
lease the [MHz] key, then press MOX (or release the
PTT key to return to the "R
FT-847 O
PERATION
RANSMIT
p] key (to raise the an-
Z
q] key (to lower the antenna).
Z
" mode.
ECEIVE
M
PERATING
" mode,
ANUAL