- IPO – Intercept Point Optimization
The IPO settings are ON, AMP1 and AMP2. If you set IPO to ON, you disable the preamp. The manual indicates that the preamp is always disabled between 30 khz and 1.7 mhz. The manual also suggests that IPO is generally not needed below 10 mhz (30m). I concur, although I often will disable IPO on 14 mhz (20m) as well. The manual suggests that if you can hear “band noise” with the preamp disabled, then the preamp isn’t needed in the first place. I again concur. This is especially true under noisy conditions, whether it be man-made noise, noise from thunderstorms and other atmospheric noise.
- DNR – Dynamic Noise Reduction
I’ve owned my FT-950 for almost a year now, and I’m still exploring the functions and finding out new things. I just decided to enable DNR this week and play around with its adjustment. I find that it is a very useful tool. It’s not meant to get rid of pulse noise. That’s what the Noise Blanker (NB) is for. The DNR can help reduce random noise / hiss / phase noise that you hear. It’s an audible thing. It doesn’t actually remove any of those noises. You’ll still see the noise indicated on an S-meter. But it will help to cancel out some noises so that you do not hear them through the speaker/headphone.
The DNR is adjustable via the Menu setting 072 RGEN DNR. An example of when I find it very useful is when I am sitting on 50.125 SSB to monitor the calling frequency. I’ll be doing other things around the house and will want the radio turned up loud enough that I can hear it when I’m in the basement. But, oftentimes there are various noises [including simple phase noise] that are really irritating to listen to hour after hour while you are waiting for some activity. I will enable DNR and will change the value of 072 RGEN DNR to something between 6 and 12. It considerably lessens the background noise and allows me to turn the radio up louder so that when an actual SSB signal is transmitting I can hear it well but I don’t have to hear as much annoying background noise when there is no SSB signal. It works really well for that.
The Yaesu manual suggests that it works best on SSB, but I find it also works well on CW. Although on CW it probably isn’t worth the effort to get into the Menu and enable/adjust DNR since there are other options available to make CW more pleasant to listen to.
To enable DNR, you press Menu, then you turn the Select knob until you get to 072 RGEN DNR (or DNR if you have your Menu set up to display the menu options in a different manner). Once you are on that menu setting, you can rotate the VFO-B knob to adjust the DNR from from OFF to 15. 1 through 15 offer differing levels of noise reduction, with 1 being minimum and 15 being maximum. Of course, there are tradeoffs when doing this, as you can really alter the readability of an SSB signal if you set the DNR too high.
You’ll need to experiment with DNR on your own, tuning to different types of signals in different conditions. You may find that on a given signal a DNR setting of 4 is great for you, whereas I might find a DNR setting of 10 great for listening to that same signal.
Don’t forget — Just like any other menu setting that you modify, if you want it to stick you need to then press Menu for a few seconds to save that setting.
- NB – Noise Blanker
If you are like me, you don’t thoroughly read the manual. For the first four months of having this radio I would periodically feel the need to turn on the noise blanker to get rid of some static / man-made noise that was randomly irritating. I was extremely disappointed each and every time I attempted to use the noise blanker, as it never appeared to significantly reduce the offending noise. I was used to the FT-100, which has an excellent noise blanker.
As it turns out, one day I held the NB button in for a couple seconds for the fun of it and realized that it goes into some other mode of operation. More importantly, when I did that the offending noise disappeared under 95% of the conditions I attempted to use it.
The manual [which I hadn't read] indicated that pressing NB button momentarily would engage a noise blanker effective for short duration pulse noise from switching transients, automobile ignitions and power lines. It goes on to state that if you hold down the NB button for two seconds it will enable Wide-NB, which is intended for longer duration man-made pulse noise. Eureka! NB-Wide works great to get rid of the most common offending noise around my QTH.
With NB on, you will notice some strangeness when listening to SSB or CW signals [and likely any signal]. I can’ describe what you might hear, but if you turn on the noise blanker and you think a CW signal is suddenly sounding strange it is probably due to the noise blanker. That’s to be expected. You don’t get something for nothing. I’ve found that the “change” in how I hear a signal when the NB is turned on is definitely a reasonable tradeoff for the removal of the static / AC / pulse noise I was hearing.
So, if you’ve never done anything more than pressed NB momentarily to try and get rid of an offending noise, you need to go one step further. In fact, there are also menu items 067 RGEN NB1 LVL and 068 RGEN NB2 LVL which can be adjusted for short duration and long duration pulse noise respectively.
- WIDTH – DSP Bandwidth
WIDTH is used along with IF SHIFT to minimize interference above and/or below the frequency you are trying to listen to. For instance, if you are listening to a CW signal you can turn on NAR to engage the narrow DSP filter. Then you can use WIDTH to adjust the width of the DSP filter with from 500 hz to 100 hz. I think 200 hz to 300 hz is optimal, although there have been times when I have used 100 hz successfully to tune in a weaker CW signal with other CW signals right above and below. The tighter [narrower] that you make the WIDTH, the more chance you will hear some ringing. I’ve read information stating that turning on APF (automatic peaking filter), which is engaged by holding down CONT for two seconds when in CW mode, will minimize ringing.
- IF SHIFT – Intermediate Frequency Shift
IF SHIFT will allow you to shift the passband of the filter higher or lower. Imagine if you had a RTTY signal tuned in and it was centered in the passband of the filter. Just inside the filter at the low end you are hearing another RTTY signal that is fairly strong. You might still be copying the intended RTTY signal, but the strong signal below it may be affecting your ability to achieve 100% copy. You could use IF SHIFT to shift the passband of the filter up 100 hz or more so that the offending signal lower in frequency than the one you are trying to copy now falls outside of the passband of the filter. I’m not an expert with filtering functions of radios, but IF SHIFT is a useful tool.
- APF – Audio Peaking Filter
When in CW mode, you can enable the APF to provide a very narrow audio bandwidth, in many cases enhancing the sound of the CW. There are no adjustments for the APF. You either turn it on or turn it off. My preference is to have it on. I find it makes CW much more pleasant to listen to. You may feel differently.
To enable APF, you want to first make sure that you are in CW mode. Once you are in CW mode, you want to push the Cont button until the CONTOUR graph on the display is not displayed. Then, push and hold down Cont for approximately 2-3 seconds and you will see a graph appear next to CONTOUR on the display. To disable, simply press Cont again.
Understand that momentarily pushing Cont will enable and disable the Contour Filter. What you want to do is make sure the Contour Filter is off and then press and hold Cont for a few seconds. The graph displayed next to CONTOUR on the radio display will look different when APF is set versus when you simply have the Contour Filter on.
- R.FILT – Roofing Filter
I must admit, either I haven’t caught on to the proper way of using the roofing filters, or the roofing filters don’t do much of anything. On a crowded band full of SSB signals during CQ WWW DX SSB I saw no appreciable difference between selecting any of the filtering options with stations in close proximity. I wouldn’t be surprised if others have had similar experiences.
If you’re reading this and feel I’m just not taking advantage of the roofing filters in the way they were meant to be used, please email me and tell me how to use these filters to my advantage. I typically set them to the narrowest value in all cases, regardless of whether I’m operating SSB, CW or digital modes.
- Yaesu FT-950 Audio Settings for my Heil ProSet