[Elecraft] K3 Noise Reduction

[Bob McGraw]

The approach I use for the Noise Blanker is this.

I first activate the NB and then the Level.   I start with the DSP OFF 
and the IF OFF.  I then adjust the DSP value for optimum results without 
it destroying the quality of the signal.  DO MAKE A NOTE OF THIS VALUE.  
Then set the DSP back to OFF.  Then move to the IF and scroll through 
the settings in an effort to find optimum results.  Once this is done, 
leave the IF value as determined and return to the DSP and set it to the 
value previously determined.

This works for a given band and given type of noise.  Change bands or 
noise and do it all again.  There is no ONE setting correct for every 
condition.   Right now my 6M noise buzz is S-7 with the NB off.  Then 
turning it ON and adjusted as above the 6M noise is S-3.  That's 4 S 
units or 24 dB improvement.  I doubt you will get much better than this.

As to Noise Reduction, I find it best performs for CW mode. Again it 
takes careful adjustment to obtain optimum results.   I don't use NR for 
SSB signals. I prefer to adjust the Attenuation value and the RF Gain to 
produce optimum results when operating SSB.   I find optimum results 
occur when the no signal band noise is about 10 dB above the receiver 
noise floor.   In order to accomplish this operating point, one will 
need to use ATTENUATION and RF Gain reduction.   More gain won't aid in 
receiving weak signals, but just the opposite, as the signal will pop 
out of the noise.

I generally find using either NB or NR, but not both, is the better way 
to operate.  I doubt there is anything wrong with your radio.  Most 
likely the result is more related to receiver setting parameters.

73

Bob, K4TAX


On 12/15/2021 9:46 AM, elecraft-request at mailman.qth.net wrote:
> Message: 15
> Date: Wed, 15 Dec 2021 09:36:26 -0500
> From: Pete Smith N4ZR<pete.n4zr at gmail.com>
> To: Elecraft List<elecraft at mailman.qth.net>
> Subject: [Elecraft] K3 Noise Reduction
> Message-ID:<dd5a2872-890f-feec-73ab-83a47b0d12ba at gmail.com>
> Content-Type: text/plain; charset=UTF-8; format=flowed
>
> Last weekend during the 10 meter contest I was experiencing very loud
> line-noise-like interference when my antenna was pointing south.? I
> tried both my K3's Noise Reduction and Noise Blanker functions, and was
> unable to find any setting that gave useful relief.? With the noise
> blanker, in particular, I noticed that when it was on, not only was the
> buzz still very strong, but it seemed as if all CW signals on the band
> were being hum-modulated.? As soon as I turned off the noise blanker,
> the CW signals cleaned up.? Is there something wrong with my radio, or
> an adjustment issue, or is this interference simply too strong??
> Obviously, I'll be trying to track it down, but it's not there all the
> time, so that could be tough.
>
> -- 73, Pete N4ZR Check out the new Reverse Beacon Network web server 
> at <http://beta.reversebeacon.net>. For spots, please use your 
> favorite "retail" DX cluster. ------------------------------ Message: 
> 16 Date: Wed, 15 Dec 2021 06:55:25 -0800 From: Dave <dave at nk7z.net> 
> To: elecraft at mailman.qth.net Subject: Re: [Elecraft] K3 Noise 
> Reduction Message-ID: <cfdb7170-cefb-9ef9-3b30-52c0bbac7b76 at nk7z.net> 
> Content-Type: text/plain; charset=utf-8; format=flowed I have that 
> same issue... I have some very dirty grow lights about two blocks from 
> me. They are dirty as they come... Splattering across 80-20 meters. 
> The K3 has never been able to adequately clean up the crud from them. 
> In defense of the NB/NR on the K3, the signals are on the order of S7 
> to S9, so my expectations may be too high for the K3. I just hope the 
> K4 NB/NR work better in my environment. 73, and thanks, Dave (NK7Z) 
> https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical 
> Specialist, RFI ARRL Asst. Director, NW Division, Technical Resources 
> ------------------------------
> Message: 17
> Date: Wed, 15 Dec 2021 08:05:59 -0700
> From: David Hachadorian<k6ll.dave at gmail.com>
> To: Pete Smith N4ZR<pete.n4zr at gmail.com>,	Reflector Elecraft
> 	<elecraft at mailman.qth.net>
> Subject: Re: [Elecraft] K3 Noise Reduction
> Message-ID:<d8b87093-eab7-ebf8-168b-175fae9fc5a4 at gmail.com>
> Content-Type: text/plain; charset=UTF-8; format=flowed
>
> For 12 years I've tried to get any enhancement of s/n from the K3 IF/RF
> NB and NR.? I haven't seen one case where there is any improvement under
> contest conditions.? When the s/n just starts to improve, the desired
> signal is modulated and degraded by nearby signals to the point where
> reception is better with NB/NR turned off.? As far as I can see, both of
> these features are useless on the K3 under contest conditions.
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
>
>