Posted by
Wes Stewart-2 on
Sep 03, 2017; 7:38pm
URL: http://elecraft.85.s1.nabble.com/Noise-Blankers-tp7634010p7634020.html
I agree. The adjustments are far too many and arcane. I'm currently plagued
with powerline noise that has yet to be fixed, although they are supposed to be
working on it. The K3S blanker is slightly better than useless. When I set it
aggressive enough to be audibly useful, FT8 decodes multiple signals at 120 Hz
intervals, which upsets sequencing.
I'm finding that my SDR-IQ that I normally use only as a bandscope, has better
noise blanking on its demodulated audio than the K3. Too bad I can't use it
with WSJT-X.
I suspect, but do not know for sure, (maybe the designer can enlighten us) that
there is insufficient delay in the (analog) signal path and the noise gets
through before blanking takes place.
Wes N7WS
On 9/3/2017 9:18 AM, K9MA wrote:
> I have never found the K3 noise blanker to be effective. On the other hand, in side-by-side comparisons, the noise blanker in my old FT-1000D can be very effective on my ever present power line noise. However, like all noise blankers of that design, it only works if there are no strong signals within many kHz of the operating frequency, so it's completely useless on a crowded band. The only way around this I know of is to use a second receiver, tuned to a clear spot nearby, to control the noise blanker.
>
> BTW, the K3 noise blanker uses a filter with a bandwidth of about 100 kHz. The idea is that, in such a wide bandwidth, the amplitude of the noise pulses should be large, making them easier to distinguish from signals. (The FT-1000 uses something like 15 kHz.) However, I've never been able to get the K3 NB to work, even on a completely dead band. Under the same conditions, I can often get a 20 dB reduction with the other radio. That I don't understand. I should investigate that sometime.
>
> 73,
>
> Scott K9MA
>
> ----------
>
> Scott Ellington
>
>
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