I've always known the HWNB was there, just never used it, until now. Thought I
would try it just to see what all the discussion was about. So I turned it on
while listening to a strong pileup on 40M where there were many signals well
over S9 (most 10-20 over). With it ON It's literally sounds like I disconnected
the antenna (actually I heard a lot more signals with the antenna
disconnected!). There were no signals to be heard and the audio level of the
remaining band noise was extremely low. After listening very closely for a few
moments and careful tuning, I was able to faintly hear one or two of the
stronger signals way down in the noise, but certainly not well enough to copy.
There is obviously a problem somewhere in the radio in need of attention but
I'll just turn it off and leave it off! If I haven't needed it before now, I
guess I can do without it!
More importantly, as usual thank you John for taking the time to communicate to
everyone about this and all other topics you weigh in on. I for one can't
express how much I appreciate the attention you give to our enjoyment and
understanding of the TenTec products.
73,
Art N4UC
> Date: Mon, 14 Oct 2013 14:58:26 -0400
> From: jhenry@tentec.com
> To: tentec@contesting.com
> Subject: [TenTec] Orion / Orion II updated reports, NB/NR/etc
>
> Hello All,
>
> I have had a few reports from customers that the receive audio sounds just
> the same as it did before regardless of QRN or impulse noise.
>
> Well, let's look at those "same as before" customers specifically.
> This set of customers ran the HW Noise Blanker on all of the time anyway
> just because they liked how it sounded with it on.
> That is fine, but, remember what the change for AGC and QRN / impulse noise
> really fixed.
> In the previous release, WHEN there was QRN or Impulse Noise or ignition or
> whatever, the AGC would falsely load up bringing audio level way way down
> in an instant, and then return after a second or so, making it interesting
> to copy or understand when there was QRN or impulse noise.
> These customers, by keeping HW NB on all of the time, were taking out the
> QRN before it ever made it to the DSP.
> So, no QRN to react to, this meant no loading up of the AGC.
> So, for them, this change, was almost a "no change".
> For others, who never use the Software Noise Blanker or the Hardware Noise
> Blanker, the reports are that the audio doesn't load up anymore, but they
> hear the QRN or impulse noise.
> Well, the answer to that is, in my opinion... turn on the HW Noise Blanker.
> Then you won't hear the QRN.
> There are other techniques, e.g. Orion and Orion II users have the SAF
> feature that they can turnon, which can be dialed up to "boost" the audio
> in the "audible tones" area that they want to listen to, and in a lot of
> cases, the extra qrn/crap will get attenuated, not always, but some of the
> time.
>
> A word about Noise featuring.
>
> They all work on different types of noise differently.
>
> Noise Blanker
> This is meant to work on impulse noise, stuff that is very short (VERY
> short duration), and sometimes very dramatic in amplitude versus the normal
> audio/noise floor. It is very aggressive and things that pop up very
> quickly and go away that are dramatic, get removed. The Software Noise
> Blanker in the Orion I/II and OMNI-VII are adjustable in their
> aggressiveness. The Software Noise Blanker is one of the first things done
> to the signal, and works on IF BEFORE AGC is applied. Hence, previous
> builds, if SW NB was turned on, AGC would not load up on QRN. Hardware
> Noise Blanker in the Orion I/II and Eagle does the same, a much better job
> though. Again, before the DSP does AGC, hence, if HW NB was on, it would
> not have loaded up the AGC.
> Either one do affect the audio though, and it is really recommended that
> unless you need it, don't use it. Some use it because it makes the RX sound
> smoother, well, it will, but it may be due to the fact that they are
> removing a bit of QRN and in previous builds, the QRN would be enough to
> load the AGC and cause some RX level changes, which sounded rougher.
> My advice with the Orion and Orion II latest releases and the OMNI-VII beta
> 1.035h, turn them off and see how well the audio now sounds. Again, it is
> subjective, if you do hear the QRN now, you should of course pick the NB of
> choice. I vote for HW NB, but, aggressiveness and effect is up to your
> ears, and your ears only.
>
> Noise Reduction.
> Noise Reduction is meant to adaptively over time adjust reception of
> broadcasted signals so that noises that are there all of the time get taken
> away. May not be a good description, but, the thing to note.... it is an
> iterative process over time, so, unlike NB that just "nails" impulses, NR
> will adjust the audio until noise that contributes to non-legibility will
> slowly go away. The faster you want it to go away is adjustable. This has a
> side effect, making it more aggressive can really ramp up/down the
> effectiveness. With the previous builds, when you had the NB's turned off,
> and you had QRN, well, the NR routine will process that QRN as well, not a
> big deal, but the big deal was the processing of the "AGC loaded up" time
> as well. So it's effectiveness in a QRN free environment might be
> excellent, but in an environment that has occasional QRN, well, not as
> good, and then more periodic QRN, well, it should never be used.
> Now, with the latest releases for the Orion and the Orion II, this effect
> is removed. SEVERAL comments coming in on how we have made such a great
> improvement in the NR. Well, we didn't touch the NR, but we did change the
> data going to the NR algorithm... before.... garbage in = garbage out...
> Now, it is a bit more effective. Probably needs some more attention itself
> down the road, but, time will tell.
> Noise Reduction works on data later in the DSP chain than the Noise Blanker
> does.
> It is also performed after AutoNotch and Manual Notch. The reason is to
> clean out tones and stuff you don't want to hear before the NR takes
> effect. In the case of FM it is done before deemphasis is applied.
> The important thing to remember, it is done after NB, and also after AGC
> would have loaded up in previous releases. So, in the latest releases of
> the Orion and Orion II, and the beta OMNI-VII 1.035h, it has a cleaner
> input to the algorithm than it did before.
>
> Now, granted, there are those that say they never have and never will use
> any kind of DSP NR/NB/whatever function to act on data.
> Their tools are the bandwidth, PBT, and for the Orion / Orion II they may
> use SAF, Hi-Cut, Lo-Cut etc to "filter" the edges and boost the internals
> of what they are listening for, and their own mind to pull the audio out
> they are listening for.
> I myself am a big fan of hardware Noise Blankers BUT, only WHEN NEEDED, and
> a lesser fan of Software Noise Blankers (but they do perform, just not as
> clean as HW does), and not so much a fan of Noise Reduction UNLESS
> absolutely necessary. The OMNI-VII for me cuts out 90% of what I'd ever
> want with it's software featuring and roofing filters.
>
> Brought up this stuff above because I think it is a good ground for
> discussions of experience amongst the group. Don't need to keep this title,
> respond with a title that makes sense for the specific area you want to
> comment on... or not... up to you.
>
> Thanks, and 73,
> John Henry, KI4JPL
> TEN-TEC Engineering
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