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Noise Blankers that actually Work?

CTStallion

Active Member
Aug 29, 2010
196
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28
Connecticut
Recently I took some 'jazzing' from some fellow Hams when they observed that in addition to a VHF transceiver, I also run either an AM/SSB CB or Export 10/11 meter rig in my mobiles. When they asked me WHY, I said: "Because MOST of the HF Amateur gear out there has noise blankers that are highly ineffective in the mobile environment." When they vehemently disagreed with me, I asked them: "Okay, here's you chance, which of YOUR mobile HF radios are completely effective in limiting and/or blanking noise in YOUR mobiles WITHOUT DISTORTION?" Dead silence...... and the look on their faces was priceless.

Now, don't get me wrong, I've run my fair share of mobile HF in over 25 states thus far. However, with virtually EVERY set up, the only way I was able to effectively deaden enough of my noise (and when I say "noise" I mean ignition, steel belted radial tire noise, traffic lights, neon lights from stores, etc.) was to run an outboard audio DSP unit into an external speaker (in my case, the old Amcomm Clear Speech DSP unit.

Of all of the HF mobile rigs I've run (4 different units), only 2 had effective noise blankers:

The FIRST was a Drake TR-7 with the NB module: too old/too big for today's compact cars.

The second was an old Alda 103 (20-40-80M analog dial) also with the optional NB module. (Not very freq. stable for mobile use.)

The two most recent mobile HF rigs were:

Alinco DX-70TH: noise blanker did NOTHING

Icom IC-706MkIIG: the internal audio DSP could only be turned up half way w/o adding rx audio distortion on SSB, and therefore was ineffective at significantly reducing received noise in the mobile environment, AND the NB was as equally ineffective as the Alinco. However, once the Clear Speech DSP unit was plugged in, it effectively eliminated over 90-95% of the noise WITHOUT the distortion of the internal DSP unit.

So my question is:

WHICH (if any) of the modern HF transceivers have NOISE BLANKERS that actually WORK as good or better than a modern CB/Export radio?
 
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2RT307

Sr. Member
Nov 22, 2011
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Texas
I couldn't agree more with your observations. I've seen the same thing. I have found the NB on my TS430 works pretty darned good in the mobile. Not a new rig, but it works. The one on my IC718? Pretty much worthless in the mobile, and I saw the same thing with the DSP on mine. Turn it up enough to work, and it makes everyone sound like a motorboat.

73,
Brett
 

w9cll

W9WDX Amateur Radio Club Member
Jan 19, 2013
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Best noise blanker I have seen is on my 101ZD, it's adjustable and does a fantastic job when needed. That being said the one on my 706mkIIg does work for ignition noise but that’s about all. As for a modern radio? Can't help you there as I don't any of the new stuff.
 

222DBFL

Sr. Member
Jul 28, 2013
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I picked up a uniden grant for my brother In law for Christmas and man it has a great noise blanker and a heck of a nice receive as well. It's an older one, but it works well.
 
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w9cll

W9WDX Amateur Radio Club Member
Jan 19, 2013
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I picked up a uniden grant for my brother In law for Christmas and man it has a great noise blanker and a heck of a nice receive as well. It's an older one, but it works well.
Is it the original Uniden model? I have one as well and they rock, well it did 20 years ago when I last used it. Maybe I should dig it out of the closet.
 

Moleculo

Ham Radio Nerd
Apr 14, 2002
9,074
1,420
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I agree that the NB on the Icom IC-7000 works pretty good in my Jeep. The NR is a little disappointing, though. I also coupled the rig with the Clearspeech speaker which is a really good combination.

The Elecraft KX3 NB is probably the best I've experienced in a while. It's better than its bigger brother, the K3 by leaps and bounds, IMO.
 

2RT307

Sr. Member
Nov 22, 2011
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Texas
I don't know enough about how noise blankers are put into the audio chain. That being said, would it be possible to replicate say, a Uniden noise blanker, and add it into the chain of the HF rig? Without the expense of the Clearspeach/whoever's Dsp module that usually run close to 200 bucks? Sure would be a neat add on.

73,
Brett
 

exces3

Member
Sep 4, 2012
54
0
16
43
is there any company that takes noise-blankers seriously?

just my opinion.

downstream of the first mixer.
there should be two or three rx paths dedicated to
(with slightly higher bandwidth, say 10khz)
NB, that could 'turn off' the main channel, before
the main channel gets saturated with noise.
these NB channels would be specialized for
both pulse and repetitive noise

73
 

w9cll

W9WDX Amateur Radio Club Member
Jan 19, 2013
4,495
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Chicago, IL
www.flickr.com
is there any company that takes noise-blankers seriously?
Modern radios? Maybe, but as posted earlier my 101zdMKIII's NB works wonderful. Its fully adjustable, there is a knob on the front panel to increase the amount. Yes you can adjust it too far where is effects the receive. I feel somehow mfg's have move away from the basics and focused of gizmo’s.
 
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M0GVZ

Sr. Member
Oct 18, 2011
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I don't know enough about how noise blankers are put into the audio chain.

Because they're not. They're put in the IF chain.

moleculo said:
The NR is a little disappointing, though.

Turn the pre-amp off. The DSP then has less to have to work with so does a better job. Also back off the RF gain as well. Backing off the RF gain seriously cuts down on noise. If you've a S7 or higher signal, having the RF gain backed down to S5 level reduces a lot of that noise and you'll still hear the S7 as clear as day.

Watch this demonstration from Bob Heil of how to get S9 of crap with everything dialled up to full down to S2-3 and far better copy by dialling in lots of attenuation which massively improves the signal to noise ratio. He dials in 12dB of attenuation and then reduces RF gain as well.

Starts at 15 minutes 23 seconds.

https://www.youtube.com/watch?v=Osp6rFf2tJU&feature=youtu.be&t=15m23s
 
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Captain Kilowatt

Professional Amateur
Staff member
Apr 6, 2005
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Because they're not. They're put in the IF chain.


That is where they SHOULD be however with the development of DSP many radios, even amateur radios, are using an audio DSP filter and calling it a noise blanker or noise limiter. Some manufacturers are going back to the IF stage which IMHO is an admission of guilt of trying to do something the cheap and sleazy way and having it not work out. Some manufacturers make a DSP speaker with "noise blanking ability" which is really just an outboard DSP filter in a speaker enclosure.
 

2RT307

Sr. Member
Nov 22, 2011
2,326
799
223
Texas
That is where they SHOULD be however with the development of DSP many radios, even amateur radios, are using an audio DSP filter and calling it a noise blanker or noise limiter. Some manufacturers are going back to the IF stage which IMHO is an admission of guilt of trying to do something the cheap and sleazy way and having it not work out. Some manufacturers make a DSP speaker with "noise blanking ability" which is really just an outboard DSP filter in a speaker enclosure.

That was my point... I'm still learning about where things go in the chain as I *try* to study for General. And there are both AF and IF types, as you mention. However, the add on DSP models aren't cheap, that's for sure. Sure would be nice as mentioned before, if they'd put a good one (like a Uniden), or the one from my Kenwood TS-430S works very well in a mobile environment, and I don't think the cost would be that much. Maybe they're in cohoots with all the outboard DSP manufactureres.... maybe it's a communist plot? :blink: :D

73,
Brett
 

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