Vertex Standard FT-1000MP manual Main receiver VFO-A if Bandwidth Filter Selection, Noise Blanker

OPERATION

DEALING WITH INTERFERENCE

NOISE BLANKER

Press the [NB] button to activate the IF Noise Blanker.

The two noise blanker circuits in the MARK- V FT-1000MPare provided for two different types of pulse noise; (A) a narrow-pulse blanker for short pulse noise such as from switching transients, automobile ignitions, and power lines, and (B) a wide pulse blanker for longer duration man-made pulse noise. This noise blanker can sometimes also reduce the level of static crashes from electrical storms You can select the de- sired noise blanker circuit (“narrow” or “wide”) and its blanking level via menu selection 2-8.

In urban environments, there may be several or even dozens of local noise sources; these may com- bine in such a way as to make detection of a clear “impulse” impossible. The IF noise blanker may, how- ever, reduce the noise level significantly, allowing the EDSP Noise Reduction feature to reduce the noise even further.

If the blanker seems to distort a signal you’re lis- tening to, reduce the setting for optimum readability, or turn it off. During periods of extreme signal density (such as a contest), the noise blanker is best left off.

IF FILTER (BANDWIDTH) SELECTION There are two banks of select-

able filters, one each for both the 8.215 MHz 2nd IF and 455 kHz

3rd IF in the Main Receiver. Filter

selections can be cascaded for versatility in combat- ting QRM and tailoring received audio. From the fac- tory, 2nd IF 500 Hz and 2.4 kHz filters and 3rd IF 2.4 kHz filter are provided. Other filters can be ordered from your Yaesu dealer. Installation instructions are cov- ered on page 113 and filter menu selections (5-0through 5-7) on pages 101 and 102. The illustration at the bot- tom of the page provides a representation of filter se- lection in the MARK-VFT-1000MP.

Select the desired bandwidth by pressing one of the [BANDWIDTH] buttons. The LEDs inside each but- ton glow red while selected.

In the AM mode, the [NOR] (6-kHz) AM-wide band- width is typically selected for both the 2nd & 3rd IF (labeled THRU on the bottom of the 2nd IF column). This gives the highest fidelity, and is best on strong AM signals (and particularly music). The effects of the SHIFT and WIDTH controls in this wide bandwidth are subtle, but they can be helpful in fine tuning the audio characteristics. For weaker AM signals, or where adja- cent channel interference is present, the [NAR 1] (2.4 kHz bandwidth) offers a compromise between inter- ference rejection and fidelity. In this case, the SHIFT and WIDTH controls can be used quite effectively to improve fidelity (see the illustrations).

However, even better reception of AM signals un- der difficult conditions can usually be had by switching to an SSB mode (whichever gives the clearest recep- tion), and superb reception of weak signals is often possible using diversity reception, described on page 46.

In SSB modes, the [NAR 2] (2.0 kHz bandwidth) button can sharply cut interference from unwanted sig- nals on either side of the desired signal (although with some necessary loss of fidelity). In CW, the [NOR] (2.0 kHz or 2.4 kHz bandwidth) is often convenient to give “a wide view” of the band when tuning around, but once a signal of interest has been found and centered in the passband, the [NAR 1] (500 Hz bandwidth) or [NAR 2] (250 Hz bandwidth) selections are much better.

In addition to selecting various filter combinations, you have several features that can be used singly, or in combination to eliminate or reduce the interference to an acceptable level. Although their use requires little more than rotating a control, it is good to have knowl- edge on how each function works and the effect on the QRM encountered.

Main receiver (VFO-A) IF Bandwidth Filter Selection

	NOR		NAR 1		NAR 2
MODE	2nd IF	3rd IF	2nd IF	3rd IF	2nd IF	3rd IF
	(8.2MHz)	(455 kHz)	(8.2MHz)	(455 kHz)	(8.2MHz)	(455 kHz)
SSB	2.4 kHz/ATTø1	2.4/6.0 kHzø1	2.0 (2.4) kHz	2.0 (2.4) kHz	N/A (2.0 kHz)	N/A (2.0 kHz)
CW	2.0/2.4 kHzø2	2.0/2.4 kHzø2	500 Hz	500 Hz	250 Hz	250 Hz
AM	ATT	6.0 kHz	2.4 kHz	2.4 kHz	2.0 kHz	2.0 kHz
RTTY/PKT/USER	2.4 kHz	2.4 kHz	2.0 kHz	2.0 kHz	250/500 Hzø3	250/500 Hzø3

ø1: You can select the bandwidth via menu selections 5-0. The forward value (bandwidth) is factory default.

ø2: You can select the bandwidth via menu selections 5-2. The forward value (bandwidth) is factory default.

ø3: You can select the bandwidth via menu selections 5-4. The forward value (bandwidth) is factory default.

page 46 MARK-V FT-1000MP Operating Manual