Att (Attenuator); Ipo; R.fil (Roofing Filter Switching) - Yaesu FTDX10 Operation Manual

Important Receiver Settings
The status of various operations that are important during receive, are shown at the bottom of the display.
To change a setting, touch the appropriate location on the display.
Important setting items when receiving

• ATT (Attenuator)

Displays the current ATT (Amount of receive input
signal attenuation).
When the desired signal is extremely strong or
the noise level is high on a low frequency band,
activate the attenuator to reduce the incoming
signal or noise from the antenna.
After touching [ATT], touch the desired attenua-
tion amount.
The attenuator is set independently for each op-
eration band.
OFF Attenuator is Off
The incoming signal power is reduced by 6dB
6dB
(Signal voltage reduced to 1/2)
The incoming signal power is reduced by 12dB
12dB
(Signal voltage reduced to 1/4)
The incoming signal power is reduced by 18dB
18dB
(Signal voltage reduced to 1/8)
• If the noise level is high or the received signal
is extremely strong, the incoming signal level
can be suppressed with the IPO/ATT settings.
If the S-meter fluctuates S-3 or more in the
noise level, or the received signal is extremely
strong and it causes a high S-meter indication
(+20dB or more), activate the attenuator.
• Since IPO does not only attenuate the incom-
ing signal, but also improves the cross mod-
ulation characteristic, try to activate the IPO
first. If the signal is still strong, also use the
ATT. In this way, you can attenuate the incom-
ing signal and noise effectively.
22

• IPO

The IPO (Intercept Point Optimization) function
can establish the gain of the RF amplifier section
to accommodate the connected antenna and the
received signal conditions. IPO can be selected
from three operating conditions.
AMP1: One stage RF amplifier is connected.
This is a well-balanced operation of re-
ceiver sensitivity and characteristics (Ap-
proximately 10 dB gain).
AMP2: Two RF amplifiers are connected in se-
ries to give top priority to sensitivity (Ap-
proximately 20 dB gain).
IPO:
The received signal is input to the IF mix-
er without passing through the RF ampli-
fier. This can greatly improve receiving,
especially in the harsh low band signal
environment.
After touching [IPO], touch the desired operating
condition.
• IPO is set independently for each operation
band.
• Normally, select "AMP1".
• The IPO can not only attenuate the input sig-
nal but also improve the intermodulation char-
acteristics. It is most effective to operate the
IPO first, and then use the ATT if the signal is
still too strong. The noise level can be attenu-
ated and S/N greatly improved.

• R.FIL (Roofing Filter Switching)

Displays the bandwidth of the currently selected
roofing filter.
Switches the crystal roofing filters of 300Hz*,
500Hz, 3kHz, and 12 kHz that are installed in this
transceiver.
Normally, filters are automatically switched de-
pending on the operation mode, however the filter
may be changed according to the conditions or
when an optional filter is installed.
Roofing filters are to be set independently for
each operation band.
*300Hz roofing filter is optional.
After touching [R. FIL], touch the desired filter.
If the optional 300Hz filter is not installed, "300Hz"
will not be displayed.