Noise Reduction; Setting Spac Time .Vevessseseessescssssssstesseseensensees; Noise Blanker; Aip (Advanced Intercept Point) - Kenwood TS-870S Instruction Manual

8 REJECTING INTERFERENCE
NOISE REDUCTION (SSB/CW/FSK/AM)
Menu No. 13 (LINE.ENH} determines whether the Line
Enhance function (an adaptive filter) or the SPAC filter is
used. When using the Line Enhance function, switch
Menu No. 18 (TRACK) ta ON. The SPAC filter works
better for reducing noise and is effective for eliminating
various types of noise. However, audio quality will
deteriorate since only the audio portion is selected. This
filter may induce pulse noises. One difference between
the digital Line Enhance function and the conventional
analog-based Noise Blanker is that the digital function
works at audio frequencies whereas the blanker acts at
IF.
Press [N.R.] to toggie the Noise Reduction function ON
or OFF.
+ The LED indicator in the button lights when the
function is ON.
+ When the S/N ratio is reasonably good in SSB, using
Line Enhance will improve the S/N further. When
receiving a CW signal with a poor S/N ratio, using
SPAC will improve the S/N. For AM signals,
received audio may become intermittent.
SETTING SPAC TIME
SPAC is a DSP term that literally means Speech
Processing using Automatic Correlation. This is one
method of digitally filtering out noise. Using Menu
No. 15 (SPAC), select the correlation time that provides
the highest quality reception for SSB. When receiving
CW, choose the longest time that allows reliable
reception. The longer the correlation time, the better the
S/N.
NOISE BLANKER
The Noise Blanker was designed to reduce pulse noise
such as that generated by automobile ignitions.
Press [NB] to toggle the Noise Blanker ON or OFF. To
cantest-type conditions, on an extremely crowded band,
or when propagation is at a peak and all signals are
local quality.
+ Press [AIP] to toggle the AIP function ON or OFF.
+ "AIP" lights when the function is ON.
¥
| cane AP kOe AuTO
(ee Og ed
ow
+ By default, AIP switches ON for all frequencies
below 7490 kHz. However, the status of AIP is
stored independently for each AIP band. When a
different AIP band is selected, the last setting
(OFF/ON) used on that band is recalled.
Note: /f you are concerned about precise S-meter readings, switch
ON Menu No. 11 (AIP.GAIN) when using this function. AIP.GAIN
does not change the S-meter sensitivity but, due to the increased
gain, the noise level increases even while receiving no signals.
AIP.GAIN does not work in FM or AM.
ATTENUATOR
The Attenuator prevents distortion by reducing the level
of the receive signal. The function is also useful to
reduce interference from adjacent frequencies.
Press ATT [DOWN] or ATT [UP] to select the desired
attenuation.
+ The selected attenuation (units of dB} lights
('— ATT -— 6", "— ATT - 12", or "— ATT - 18").
fo saat acc auTo
fa = i
B 39655a |
t
|
\ |
\
The status of ATT is stored independently for each
change the jevel of blanking, adjust the NB control. ATT band. When the ATT band is changed, the last
Always use the minimum necessary blanking. This setting used on the band is recalled.
reduces the chances of blanking your desired signal.
5
a e
Frequency Range
| Default AIP) Defauit ATT
+ "NB" lights when the function is ON. (MHz) Setting Setting
.
1 | Lowesttreg ~249 | ON
| OFF
!
fare
a
| 2
2.49 ~ 4.49
| ON | OFF
'
Me
Sea
i
' 4 9 ~7.
» ON
FF
i {426300 (ee Sees 2
ie | 4 7.49~1049 | OFF OFF
5 10.49 ~14.49 «OFF OFF
+ When receiving a strong signal while the Noise 2 FF FE
Blanker is ON, receive audio may sound distorted. 2 158 e029 ae 2
Eliminate the distortion by reducing the Noise 7 20.99 ~ 21.99 | OFF OFF
Blanker level, or by switching OFF the function. a. 94.99 ~ 25.49 OFF OFF
9 | 25.49 ~ 30 | OFF | OFF
AIP (ADVANCED INTERCEPT POINT)
AIP helps eliminate interference and reduce audio
distortion that is sometimes caused by the presence of
strong signals. AIP is especially useful during
Note. The lower limit is insioe the band in each case: the higher
limit is inside the next higher band. For example. 4.49 MHz ss in
Band 3 whereas 7.49 MHz is in Band 4 fexception: 30 MHz is in
Band 9),
53