Manual Tuning - Yaesu FT-857D Operating Manual

A -T
CTIVE UNING
6. When you wish to conclude ATAS-100/-120 operation, press the [ A ]( TUNE ) key; the
"u" icon disappear surrounding the "ATAS" indication.
If the ATAS-100/120 retracts to its minimum length, it will not automatically shut
off instantly; it may continue to have its motor engaged for as long as 30 seconds
thereafter, until a timer expires. A clutch mechanism prevents damage to the antenna
while this is happening, and this condition is completely normal.

Manual Tuning

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 40 meters, where the "Q" of the
ATAS-100/-120 is high, causing a narrow resonance range.
To tune the ATAS-100/-120 manually, recall Multi Function Row "k" [ TUNE, DOWN, UP ] ,
then press and hold in the microphone PTT switch. With the transceiver in the "transmit"
mode, press and hold in the [ C ]( UP ) key (to raise the antenna) or the [ B ]( DOWN ) key (to
lower the antenna). While you hold in one of these keys, the FT-857 will generate a carrier,
and you may watch the top scale of the FT-857's meter, looking for the meter indication to
reach its minimum value. When this is reached, release the [ C ]( UP ) or [ B ]( DOWN ) key,
then release the PTT key to return to the "receive" mode.
R.F. Says: 1) Once automatic matching has been successfully accomplished, you must
change frequency by at least 10 kHz before attempting automatic matching again. Within
a window of ±10 kHz from a match point, the transceiver's microprocessor will
ignore any command to attempt automatic matching.
2) Antenna tuning is accomplished using a "CW" carrier, although the mode indication
will not change to "CW" (if you are operating on another mode) during antenna tuning.
3) If you see a "HSWR" on the LCD, it may mean that there is a problem in your coaxial
cable (bad connection, etc.) which is preventing successful tuning. Replace the cable, or
try adding a few feet/meters of cable (to eliminate the possibility of adverse "transformer
action" in the 50 W cable during the tuning process).
4) If you are able to achieve an SWR of less than 2:1 via manual tuning, the FT-857 will
"accept" the manual setting, and you may then re-tune automatically when changing
bands. If, however, you stop manual tuning at a non-optimum setting (SWR >2:1), the
FT-857 will not permit further automatic tuning. To refresh the setting of the ATAS-100/
-120, press the [ B ]( DOWN ) key until the ATAS-100/-120 fully retracts. You may then
restart automatic tuning per the procedures described earlier.
5) The FT-857 may also be used with the model ATAS-100 antenna, although the tuning
speed of the ATAS-100 will be about 20% slower than with the ATAS-120.
FT-857 Operating Manual
T
RANSMITTER
A S
NTENNA YSTEM
O
( ATAS-100/-120 ) O
PERATION
PERATION
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