Yaesu FT DX 9000MP CONTEST - DATA MANAGEMENT..., Руководство по эксплуатации

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Page 65 FT
DX
9000MP O
PERATION
M
ANUAL
IPO
(
I
NTERCEPT
P
OINT
O
PTIMIZATION
)
Normally, the front-end FET RF amplifiers provide maximum sensitivity for weak signals. During typical conditions on
lower frequencies (where strong signals and high noise are common), the RF amplifiers can be bypassed by pressing the
[
IPO
] button so that the button's illumination is lit. This improves the IMD (intermodulation distortion) rejection character-
istics of the receiver, with only a slight reduction of sensitivity. On frequencies below about 10 MHz, you generally will
want to keep the [
IPO
] button engaged at all times, as the preamplifiers are usually not needed at these frequencies unless
you are using a Beverage or other lossy receive antenna.
M
AIN
(VFO-A) IPO S
ETUP
Press the Main (VFO-A) side’s [ -IPO switch
] key
to engage the IPO on the Main band (VFO-A).
A Red LED imbedded in the switch will light up, and the
preamplifier for the Main (VFO-A) receiver will be by-
passed. The system gain and sensitivity will be reduced.
To cancel IPO operation and restore full system gian and
sensitivity, press the [
-IPO switch
] key once more.
SUB(VFO-B) [ -IPO] Switch
MAIN(VFO-A) [ -IPO] Switch
CCCCC
ONVENIENT ONVENIENT
ONVENIENT ONVENIENT
ONVENIENT
F F F F F
EA EA
EA EA
EATURES TURES
TURES TURES
TURES
Q Q Q Q Q
UICK UICK UICK UICK UICK
N N N N N
O O O O OTE TE TE TE TE
The FT
DX
9000MP ’s first mixer is an active type, using four SST310 Junction FETs. This mixer design provides
gain to the receiver chain, so the noise figure of the receiver is fundamentally lower than with some other designs.
Therefore, it frequently is not necessary to utilize the RF preamplifier, and the receiver Intercept Point will be
substantially increased by engaging IPO, so as to feed the incoming signals directly to the first (active) mixer. We
recommend that IPO be switched on whenever possible.
S
UB
(VFO-B) IPO S
ETUP
Press the Sub (VFO-B) side’s [ -IPO switch
] key to
engage the IPO on the Sub band (VFO-B).
An Umber LED imbedded in the switch will light up, and
the preamplifier for the Sub (VFO-B) receiver will be by-
passed. The system gain and sensitivity will be reduced.
To cancel IPO operation and restore full system gain and
sensitivity, press the [
-IPO switch
] key once more.
VDD TEMP SWR BIAS