Ipo; Att (Front End Attenuator) - Yaesu FT-857D Operating Manual

R
ECEIVER
IPO ( I
The IPO feature bypasses the receiver RF preamplifier, thereby eliminating the preamp's
gain. This feature is not available on the 144 MHz and 430 MHz bands.
1. Press the [ FUNC ] key momentarily, then rotate the SELECT knob, as needed, until
Multi Function Row "m" [ IPO, ATT, NAR ] appears on the display.
2. Press the [ A ]( IPO ) key to bypass the receiver input preamplifier. The "u" icon will
appear at the left side of the "IPO" selection, and the " " icon will appear on the display. .
indicating that the preamp is now disengaged from the receiver circuit.
3. Press the [ A ]( IPO ) key once more to re-activate the preamp.
On the bands below 14 MHz, the input preamplifier is rarely necessary, and acti-
vation of the IPO feature will provide substantial protection against intermodulation
and other problems associated with strong signal input to the receiver. Rule of thumb: so
long as the S-meter is moving on background noise, additional front-end gain is not
necessary.
The Attenuator will reduce all signals (and noise) by 10 dB, and it may be used to make
reception more pleasant under extremely noisy conditions. This feature is not available on
the 144 MHz and 430 MHz bands.
1. Press the [ FUNC ] key momentarily, then rotate the SELECT knob, as needed, until
Multi Function Row "m" [ IPO, ATT, NAR ] appears on the display.
2. Press the [ B ]( ATT ) key to activate the Attenuator. The "u" icon will appear at the left
side of the "ATT" selection, and the " " icon will appear on the display. .
3. Press the [ B ]( ATT ) key once more to switch the Attenuator out of the receiver front end
circuit. Signals will again be received at a level 10 dB louder than was the case when the
Attenuator was engaged.
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A
CCESSORIES
NTERCEPT
ATT ( F
RONT
P O
OINT PTIMIZATION
E A
ND TTENUATOR
FT-857 Operating Manual
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