[Skimmertalk] Notching out FT8 frequencies to reduce CPU load of RTTYSkimServ

Martin Rath martin.rath at gmail.com
Sat Jun 16 04:25:00 EDT 2018


Hi Bob,

Thanks for the tip. I just did the modification

The i7-8700k didn't really need it here but it may come handy on contest
days.

73's Martin 9V1RM

On Sat, Jun 16, 2018 at 1:23 PM, Bob Wilson, N6TV <n6tv at arrl.net> wrote:

> Depends on your hardware and sampling rate.  Use 192 kHz sampling if
> possible to cover the most frequencies.
>
> See https://groups.io/g/RBN-OPS/message/1793 for more info.
>
> For QS1R, see
>
> http://reversebeacon.blogspot.com/2014/01/want-to-spot-
> beacons-heres-how.html
>
> 73,
> Bob, N6TV
>
> On Fri, Jun 15, 2018, 9:55 PM Ron Castro <ronc at sonic.net> wrote:
>
> > Bob:  What should the center frequencies be set for?
> >
> >           Ron Castro
> >            N6IE
> >     www.N6IE.com
> >
> > Member:
> >                   ARRL
> >      Redwood Empire DX Assn.
> > Northern California Contest Club
> > Northern California DX Foundation
> >   Society of Broadcast Engineers
> >
> > -----Original Message-----
> > From: Skimmertalk <skimmertalk-bounces at contesting.com> On Behalf Of Bob
> > Wilson, N6TV
> > Sent: Friday, June 15, 2018 3:30 PM
> > To: SkimmerTalk Reflector <skimmertalk at contesting.com>
> > Subject: [Skimmertalk] Notching out FT8 frequencies to reduce CPU load of
> > RTTYSkimServ
> >
> > Clicking on the "Band scope" button in RTTY Skimmer Server reveals that
> > RTTY
> > Skimmer creates a *lot* of "decoders" (yellow dots) as it attempts to
> > identify and process signals that it cannot possibly deal with.  This
> > wastes
> > a lot of the CPU time.
> >
> > To reduce the CPU load, I changed the RTTYSegment section of my
> > RTTYSkimServ.ini file to ignore most of the known FT8 frequencies between
> > 80m and 15m where most of the activity seems to be (at present):
> >
> >
> > RttySegments=1800000-1820000,3520000-3571000,3577000-
> 3600000,5330000-5407000
> >
> > ,7020000-7071000,7077000-7100000,10130000-10132000,
> 10139000-10150000,1406000
> >
> > 0-14071000,14077000-14150000,18109000-18115000,21060000-
> 21071000,21077000-21
> > 150000,24910000-24930000,28060000-28150000,50250000-54000000
> >
> > (Of course this statement must be on a  *single long line*; email
> programs
> > may show this statement as multiple lines due to line wrap).
> >
> > The reduction in CPU utilization was immediate and noticeable.  My
> i7-7700
> > PC has a variable speed cooling fan, the higher the CPU utilization, the
> > louder the fan.  It's much quieter now, and I'm still decoding RTTY spots
> > just fine.
> >
> > I'm not sure if I should remove these FT8 frequencies during RTTY contest
> > weekends.  Last time I checked, the FT8 guys were still going strong with
> > little if any RTTY contest activity in the FT8 frequencies, but I haven't
> > tried to analyze the raw data files to see how many RTTY spots were
> posted
> > to these FT8 frequencies that I'm now ignoring.
> >
> > 73,
> > Bob, N6TV
> > _______________________________________________
> > Skimmertalk mailing list
> > Skimmertalk at contesting.com
> > http://lists.contesting.com/mailman/listinfo/skimmertalk
> >
> >
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