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| 8 REJECTING INTERFERENCE | |
NOISE REDUCTION (SSB/CW/FSK/AM) | ||||||
Menu No. 13 (LINE.ENH) determines whether the Line | or when propagation is at a peak and all signals are | |||||
local quality. | ||||||
Enhance function (an adaptive filter) or the SPAC filter is | ¥ |
| Press [AIP] to toggle the AIP function ON or OFF. | |||
used. When using the Line Enhance function, switch |
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Menu No. 18 (TRACK) to ON. The SPAC filter works | ¥ |
| ÒAIPÓ lights when the function is ON. | |||
better for reducing noise and is effective for eliminating |
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various types of noise. However, audio quality will |
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deteriorate since only the audio portion is selected. This |
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filter may induce pulse noises. One difference between |
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| AIP AGC AUTO | |
the digital Line Enhance function and the conventional |
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| CW | ||
works at audio frequencies whereas the blanker acts at |
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IF. | ¥ |
| By default, AIP switches ON for all frequencies | |||
Press [N.R.] to toggle the Noise Reduction function ON |
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| below 7490 kHz. However, the status of AIP is | ||||
or OFF. |
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| stored independently for each AIP band. When a | |||
¥ The LED indicator in the button lights when the |
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| (OFF/ON) used on that band is recalled. | ||||
function is ON. |
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¥ When the S/N ratio is reasonably good in SSB, using | Note: If you are concerned about precise | |||||
ON Menu No. 11 (AIP.GAIN) when using this function. AIP.GAIN | ||||||
Line Enhance will improve the S/N further. When | ||||||
does not change the | ||||||
receiving a CW signal with a poor S/N ratio, using | gain, the noise level increases even while receiving no signals. | |||||
SPAC will improve the S/N. For AM signals, | AIP.GAIN does not work in FM or AM. |
received audio may become intermittent.
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 .
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 change the level of blanking, adjust the NB control. Always use the minimum necessary blanking. This reduces the chances of blanking your desired signal.
¥ÒNBÓ lights when the function is ON.
AGC AUTO | NB |
| WIDTH |
USB
¥When receiving a strong signal while the Noise Blanker is ON, receive audio may sound distorted. Eliminate the distortion by reducing the Noise Blanker level, or by switching OFF the function.
AIP helps eliminate interference and reduce audio distortion that is sometimes caused by the presence of strong signals. AIP is especially useful during
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 (ÒÐ ATT Ð 6Ó, ÒÐ ATT Ð 12Ó, or ÒÐ ATT Ð 18Ó).
AGC AUTO
LSB
¥The status of ATT is stored independently for each ATT band. When the ATT band is changed, the last setting used on the band is recalled.
Band | Frequency Range | Default AIP | Default ATT | |
No. | (MHz) | Setting | Setting | |
1 | Lowest freq. ~ 2.49 | ON | OFF | |
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2 | 2.49 | ~ 4.49 | ON | OFF |
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3 | 4.49 | ~ 7.49 | ON | OFF |
4 | 7.49 ~ 10.49 | OFF | OFF | |
5 | 10.49 ~ 14.49 | OFF | OFF | |
6 | 14.49 | ~ 20.99 | OFF | OFF |
7 | 20.99 | ~ 21.99 | OFF | OFF |
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8 | 21.99 | ~ 25.49 | OFF | OFF |
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9 | 25.49 ~ 30 | OFF | OFF |
Note: The lower limit is inside the band in each case; the higher limit is inside the next higher band. For example, 4.49 MHz is in Band 3 whereas 7.49 MHz is in Band 4 (exception: 30 MHz is in Band 9).
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