Yaesu FT-857D Mode D’Emploi
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FT-857 Operating Manual
Antenna Tuner Memory System
The FC-30, working in concert with the FT-857, can store impedance matching data in its
micro-computer memory, so as to provide instant adjustment as you transmit in different
areas of a particular band. A total of 100 memories are provided: 11 of these are “general”
memories apportioned one per band, while the remaining 89 are allocated for specific fre-
quency data within the various bands, with the capability to resolve new tuning data every
10 kHz.
micro-computer memory, so as to provide instant adjustment as you transmit in different
areas of a particular band. A total of 100 memories are provided: 11 of these are “general”
memories apportioned one per band, while the remaining 89 are allocated for specific fre-
quency data within the various bands, with the capability to resolve new tuning data every
10 kHz.
A few guidelines should be noted regarding the FC-30’s memory system:
Tuning data is stored when you make an active effort to store it by pressing and holding in
the [A](TUNE) key for one second. Although the tuner will automatically activate itself if it
encounters more than 1.5:1 SWR, this memory will not be stored unless you have pressed
the [A](TUNE) key for one second. This allows you to store your favorite operating fre-
quency areas into tuner memory without tying up memory space with matching data on
seldom-used frequencies.
the [A](TUNE) key for one second. Although the tuner will automatically activate itself if it
encounters more than 1.5:1 SWR, this memory will not be stored unless you have pressed
the [A](TUNE) key for one second. This allows you to store your favorite operating fre-
quency areas into tuner memory without tying up memory space with matching data on
seldom-used frequencies.
If the FC-30 cannot resolve a satisfactory match because the SWR is above 3:1 (2:1 on the
50 MHz band), the tuning process will stop, and no memory data will be stored. However,
you may wish to move frequency a few kHz, then press the [A](TUNE) key again for one
second, as slight changes in the reactance may allow a match to be obtained. Then go back
to the original frequency and try again.
50 MHz band), the tuning process will stop, and no memory data will be stored. However,
you may wish to move frequency a few kHz, then press the [A](TUNE) key again for one
second, as slight changes in the reactance may allow a match to be obtained. Then go back
to the original frequency and try again.
Another technique which may allow matching in some situations is to add a few feet or
meters of coaxial cable on the “antenna side” of the FC-30. This will change the impedance
transformation taking place in the coaxial cable, possibly moving the impedance presented
to the FC-30 into an acceptable range. Note that this is not changing the actual antenna
SWR, but only the impedance “seen” by the FC-30’s matching circuits.
meters of coaxial cable on the “antenna side” of the FC-30. This will change the impedance
transformation taking place in the coaxial cable, possibly moving the impedance presented
to the FC-30 into an acceptable range. Note that this is not changing the actual antenna
SWR, but only the impedance “seen” by the FC-30’s matching circuits.
If your antenna system presents an SWR of less than 1.5:1, you may wish to turn off the
antenna tuner, as full transmitter power will be delivered to the antenna system without
intervention by the FC-30.
antenna tuner, as full transmitter power will be delivered to the antenna system without
intervention by the FC-30.
If the impedance encountered by the FC-30 exceeds 3:1, and the “HSWR” icon is illumi-
nated, the microprocessor will not retain the tuning data for that frequency, as the FC-30
presumes that you will want to adjust or repair your antenna system so as to correct the high
SWR condition.
nated, the microprocessor will not retain the tuning data for that frequency, as the FC-30
presumes that you will want to adjust or repair your antenna system so as to correct the high
SWR condition.
T
RANSMITTER
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PERATION
FC-30 A
UTOMATIC
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UNER
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PERATION