Wouldn't the timescale based on leading edge TOF, be the rise time of the pulse?
For triangulating on lightning bolts by TOF, rise time doesn't seem to be a limiting factor because lightning bolts are fast enough to be broadband across many MHz. But for ham CW transmissions (which would include many tuner-uppers as well as the kc cop QRM) rise time is milliseconds. A millisecond in time, is 200 miles, and I would expect a half dozen hams with beams or directional arrays correlating their headings would be superior. I have no doubt NSA and maybe FCC can avoid rise time limits through true interferometry. Tim N3QE On Tuesday, February 10, 2015, Charlie Cunningham < [email protected]> wrote: > 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:[email protected] <javascript:;>] On > Behalf Of Jim > Garland > Sent: Sunday, February 08, 2015 9:08 PM > To: 'Lee K7TJR'; [email protected] <javascript:;> > 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:[email protected] <javascript:;>] On > Behalf Of Lee > K7TJR > > Sent: Sunday, February 08, 2015 4:47 PM > > To: [email protected] <javascript:;> > > 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 > > > > > _________________ > > _________________ > > Topband Reflector Archives - http://www.contesting.com/_topband > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
