[CQ-Contest] DSP units with great noise reduction

Michael Walker va3mw at portcredit.net
Thu Oct 22 10:36:38 EDT 2020


I have to say that 80% of the noise that impacted me on the low bands (and
even 2M) was in my house.  The worst was a Cisco switch that wiped out from
1Mhz - 240Mhz.  It was the switch I was using in the shack.  It had some
amazing broad spurs that landed on key RF frequencies.

I spent a few days going around with a Handheld that had AM on it and
narrowing it down.  I replaced about a dozen wall chargers (Garmin and
Apple being the worst).

I added Mix 31 and 43 chokes to both ends of every feedline depending on
the frequency.  This also includes DC power cables.  I ended up buying
about 100 of each and I have used most of them.

It was the Yankee Contest Clipper Club document on choking that got me to
dig in further into my own home.  I would share the link, but I think it
would be stripped out.  You can easily Google it.

If you have 100% eliminated everything internal to your QTH, that you can
ignore my comments.  hi hi

Good luck in the contest, Mike va3mw

On Thu, Oct 22, 2020 at 10:04 AM Martin, LU5DX <lu5dx at lucg.com.ar> wrote:

> Hello John,
> In my case I use several things.
> I have two noise cancelling units:
> QRM Eliminator by SP8RSM
> These are no DSP but rather X-Phase type.
> I owned a Timewave DSP599zx which worked okay in many aspects, like with no
> specific EMI sources.
> I sold it when I bought the FTDX3000D.
> This rig is great. I have tested it during SSB and CW contests. On CW with
> the optional 300Hz roofing filter it simply outperforms other rigs I have
> used like, IC7851, K3S, IC7700, IC7600.
> The noise reduction capabilities are pretty good.
> I think you may have to experiment fighting the QRM based on what's present
> at your location though.
> Eventually you may want to explore with software using Linrad for example
> as a last step in your noise-fighting artifacts chain.
> Some videos on YouTube that may give you an overview:
> QRM Eliminator:
> https://youtu.be/0KJai82eP2g
> https://youtu.be/efyJRS3jbOI
> Linrad
> https://youtu.be/rWm38BW2-TI
> I would really suggest you consider the DX Engineering NCC2
> Vy 73,
> Martín, LU5DX
> El mié., 21 oct. 2020 10:19 p. m., John Geiger <af5cc2 at gmail.com>
> escribió:
> >  I made a rather serious effort in the Illinois QSO party today since I
> > used to live in IL and know a few of the operators in the contest, plus
> it
> > is only an 8 hour effort-but I wish they would move it away from football
> > season!  Conditions weren't the best, but I was really suffering from
> noise
> > on 40 meters-not one specific noise source, just the crud you get from
> > living in an urban neighborhood with lots of consumer electronics and
> their
> > crummy switching power supplies and other noise makers.  I am sure I am
> not
> > the only ham with this issue.  The noise reduction circuit in my current
> > rig didn't do the greatest on handling this noise.
> >
> > One idea that came to me, that would be cheaper than a new rig (but less
> > fun) would be an outboard DSP unit.  Does anyone have any recommendations
> > on DSP units that have good noise reduction circuits?  I have seen some
> > reviews on the Clearspeech and GAP speaker units that said that after you
> > unkey after transmit you are hit with a burst of noise until the unit
> > readapts itself to the receiver noise. I don't want something with that
> > issue.
> >
> > Recommendations?  Also, what radios are really good at dealing with this
> > type of noise.  I have seen the FTDX3000 and K3 mentioned as having great
> > noise reduction circuits.
> >
> > 73 John AF5CC
> > _______________________________________________
> > CQ-Contest mailing list
> > CQ-Contest at contesting.com
> > http://lists.contesting.com/mailman/listinfo/cq-contest
> >
> _______________________________________________
> CQ-Contest mailing list
> CQ-Contest at contesting.com
> http://lists.contesting.com/mailman/listinfo/cq-contest

More information about the CQ-Contest mailing list