Topband: K1N DQRM Tracking Project

[Jim Garland]

Hi Charlie,
You/re right of course, it's 1 ft/nanosecond. Don't know what I was
thinking.  I was also focusing on CW DQRM,  since that is 99% of what I
operate, and since carriers and CW jamming havw been endemic on the Navassa
dxpedition's top band and 80m operations. I agree that for SSB interference,
the concept would be harder to implement since there would be no sharply
defined turn-on time for the interference at the receiving stations. 

I was also envisaging receiving stations spaced, e.g., 100 miles or more
apart,  and for those the time delays coould be a msec or longeer, and not
just a phase shift.  Of course, multipath and ionisspheric reflection would
be a problem on the higher frequentices, although the accuracy would be
improved with more than three receiving stations. I've nothing against
direction finding, but that's likely to have much more inherent error than a
technique which involves only time measurements.

For topband DQRM, I've assumed most of the jamming came from US stations,
but that's just a guess.
73,
Jim W8ZR

> -----Original Message-----
> From: Charlie Cunningham [mailto:charlie-cunningham at nc.rr.com]
> Sent: Monday, February 09, 2015 11:54 PM
> To: 'Jim Garland'; 'Lee K7TJR'; Topband at contesting.com
> Subject: RE: Topband: K1N DQRM Tracking Project
> 
> Actually ,Jim,  the velocity of propagation of radio waves (or light
waves)
> in free space is about 1 foot/nanosecond, NOT 1 foot per microsecond. It
> would seem to me that one needs to have a measure of directivity as well a
s
> time, an  the time factor might boil down to phase difference
measurements.
> Thinking of applying all of this to something complex like SSB modulation
> sounds pretty messy. And a lot of the interference originates outside our
> borders, so I don't see who would be the enforcement body?
> 
> 
> Just my $0.02
> 
> 73,
> Charlie, K4OTV
> 
> 
> -----Original Message-----
> From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Jim
> Garland
> Sent: Sunday, February 08, 2015 9:08 PM
> To: 'Lee K7TJR'; Topband at contesting.com
> Subject: Re: Topband: K1N DQRM Tracking Project
> 
> I agree, Lee. Locating a DQRM station involves accurately time stamping
the
> arrival time of their transmissions, at (at least) three receivers at
known
> locations. Once the arrival times are known, one can use trigonometry to
> calculate the location of the interfering station. Since radio waves
travel
> about one foot in a microsecond, and since a microsecond is an eternity by
> modern frequency counter standards, it should be possible to get very
> precise locations. The city block mentioned earlier should be readily
> doable. Of course, this requires that the three receivers be able to copy
> the DQRM ground wave signal, since the arrival times would otherwise be
> dependent on ionispheric reflections. More than three receivers would
result
> in more accurate position measurements.. There's no need to use direction
> finding equipment, which are very low resolution by comparison with time
> measurements..
> 
> I'm no authority on FCC rules, but I'm under the impression that
> deliberately interfering with other licensed transmissions is against the
> law. Every month or so, the FCC nails some renegade ham or CBer for doing
> just that. Probably just publicizing the callsign of the culprits would be
a
> large deterrant for all but the most sociopathic offenders.
> 73,
> 'Jim
> 
> > -----Original Message-----
> > From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Lee
> K7TJR
> > Sent: Sunday, February 08, 2015 4:47 PM
> > To: topband at contesting.com
> > Subject: Re: Topband: K1N DQRM Tracking Project
> >
> >
> > Greetings top-band community,
> >
> > Interestingly enough the technology exists right here in our own Ham
> > community that could go a long way toward finding these DQRM culprits.
> >     There are some beam forming arrays that operate with SDR
> > technology where a recording can be made of a target bandwidth and
> > later reviewed
> with
> > beam forming techniques to DF using a peak or notch completely after
> > the event has long gone. In fact directional and strength data can be
> > stored
> in
> > perpetuity.
> >  So my comment is don't underestimate the ability to identify these
> idiots.
> >   Being able to actually replay an entire contest and do a strength
> > and directional analysis in a narrow bandwidth after the fact to me is
> > the ultimate receiving system.
> >
> > Lee K7TJR   OR
> >
> >
> > <I'd be interested in some project like that, but I'm afraid it would
> > only get to a general area. With maybe 3-10 idiots at any one time,
> > and the
> 3-10
> > active at any time probably varying every hour, it might be pretty
> > tough
> to
> > do anything meaningful.
> >
> > Since attention is what they want, I wonder if this effort would not
> > encourage participation in jamming at a faster rate than it solves
> anything?
> >
> > Has anyone ever looked to see if there is any correlation between
> > intentional QRM and the DX station spreading people over a wide swath
> > of
> the
> > band? More than once, I've heard people intentionally threaten to QRM
> > DX because they were POed that their QSO was interrupted by a pileup.>
> >
> > <73 Tom >
> >
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