[CQ-Contest] Noise Blanker recommendations

[Charles Harpole]

John, I have monster noise here near Bangkok and have tried several things.
-ICOM IC-775dsp is jaw dropping good on radiated high voltage lines (it was
made during the Russian woodpecker era), but can be defeated by other noise
sources.

-Yaesu FT-9000d has three built-in 'preselectors' ("RF u-tune" name) which
are amazing on all kinds of noise but with strong noise, they lower the
level but do not eliminate.  Astonishingly good on radiated noise, but not
a total solution.  See
https://www.dxengineering.com/search/product-line/yaesu-rf-mu-tune-kits-and-units/fits-transceiver-model/ftdx-9000/quantity/sold-individually
.

-K3 has about 16 settings for noise, all interwoven so that change one
setting, it affects all the others.  Extensive adjusting of these will find
one which works well but does not totally eliminate my noise (which is
different at different times, requiring inordinate time to readjust).

-ICOM IC-7800 seems better on some types of noise, like nearly knock out
one kind while not too good on others.

These radios I have personally tested side by side.

The *best *solution is the MFJ 1025 "Noise Cancelling Signal Enhancer"
because it is a phasing tuned unit requiring two antennas.  In my case with
noise coming from NE, N, and NW only, this device absolutely eliminates my
noise while leaving the desired signals untouched.  It requires only one
session of adjusting, but has one astonishing draw-back: it will stand very
little RF on the second antenna input so as to limit 1.5KW operation near
its ants.... it needs a COR relay there.  Phasing is your answer because it
really works.  The built in antenna on the MFJ-1026 was not tested.

Of course there are a myriad of noise types and sources.  Mine are all
radiated so the MFJ is great.  Noise coming thru the AC supply line have
other solutions discussed elsewhere.  GL, 73, Charly HS0ZCW

On Mon, Oct 23, 2017 at 9:27 AM, John Geiger <af5cc2 at gmail.com> wrote:

> I was making a rather serious (given my small antennas) effort today in the
> Illinois QSO Party and had to deal with this intermittent noise I have here
> for pretty much the entire contest.  It is a raspy, hash type noise that
> will be on for 2 or 3 seconds, then will end, but come back every 20 to 30
> seconds.  I  have figured out it is not in my house, and doesn't seem to be
> power line noise.  At one time I thought I had localized it to a house
> about 4 houses to the west of me, but the house is now unoccupied, but the
> noise is still there.
>
> Anyways, I was using the Kenwood TS950SD which I just picked up, and it is
> a great rig with lots of receiver tools.  The noise blanker pretty much
> knocked out the noise, but it also produced plenty of IMD products when the
> band got busy and put a raspy sound on many of the signals, so I was having
> to turn the NB off and on trying to make the signals as best as I could
> with this noise.  Even engaged the attenuator a few times on 40m which
> helped a little, but also weakened signals.
>
> I have had a slight windfall recently and can afford to get a newer, better
> rig if I want.  Are there any recent contest quality rigs that have noise
> blankers that take out many different types of noise, but don't mess with
> the receive signals and receiver dynamic range?  I wonder if the DSP based
> noise blankers are better?  An older rig would be ok also if it would meet
> those criteria.
>
> 73 John AF5CC
> _______________________________________________
> CQ-Contest mailing list
> CQ-Contest at contesting.com
> http://lists.contesting.com/mailman/listinfo/cq-contest
>



-- 
Charly, HS0ZCW