Interview With The Tarsacci Inventor Dimitar Gargov

[Steve Herschbach]

Back to if the transmit side pulses, it is a pulse, regardless of what the receive end is doing. But honestly it’s just word games, defining terms, and those definitions change all the time in the real world. Obviously you can design new ways of doing things, and then we try to come up with words to define them. It is one of our traits as humans - assigning labels. It does become important in communications though that we define terms, otherwise they get tossed around and confuse rather than enlighten. All I know is the marketers are going to turn this hybrid stuff into a meaningless muddled mess in the next few years. Ultra Maximum Mixed Mode Multifrequency Time Domain Technology With Super Phase Processing!

Whatever. I think our skill set is different Keith. Give me a detector and I just turn it on and listen to it. They talk to me. Move this knob, they get happy, or they protest. They all have a language and you just have to learn it and listen. As you say, I can feel what they detector is trying to do, what it is saying to me.

I do think though that having some basic grasp of how these things work matters from an operational perspective. It explains why certain things happen in the field, and what might be done to address those things. If people really understood what a Gain control does, for instance, they would be less likely to insist it always be on max. But many people think of a Gain control as a depth control, and refuse to “turn down the depth”, when in fact turning the Gain down could increase the useable depth. That is why so many people seek canned settings... they really do not have a clue what the controls are actually doing.

[Keith Southern]

Yes Steve ive decided the transmission method of the machine whatever it may be is not as important as the Salinity balance.whatever that really is? and how it works.

That is the true DNA of the unit.and yes your detailed report on salinity balance once you use it you will see it causes P.I. timing type effects.very reminescent traits will be noticed.

Your very astute in your deciphering.!!!

Keith

 

[Geotech]

I've been reading through Dimitar's patent today. It uses a square wave (voltage) transmitter which produces a triangle wave current. When the coil is non-ideal (due to resistance) the triangle wave becomes slightly exponential, especially at lower frequencies. The patent describes an analog correction process after the preamp that compensates for this. Then it describes a the possibility of multiple demod stages (I/Q pairs), each with a preceding notch filter. One demod pair has a notch filter for ground, the others have different notches for different target responses. That's as far as I got, these things are tough to read. I fell asleep twice.

Bottom line is, the Tarsacci is 100% continuous-wave VLF. It is NOT sinusoidal like most single-frequency VLFs, but the demods are continuous-time just like SF-VLFs so it does not use time-domain demodulation like BBS/FBS. However, the preprocessing before the demods is done in time-domain fashion, so overall I would call it mixed time/frequency domain. I have to admit, I've not seen things done quite like this.

My own developments have included square-wave drive designs and I've considered coil compensation methods but at this point I've pushed it into DSP. But I understand exactly what Dimitar is doing there. The ground/target notching is more interesting to me and I think I know what he's doing but I need to keep reading.

Congratulations to Dimitar on a different and clever solution. Too bad FTP didn't hang on to him.

 

[Carolina]

I for one hope you continue to study his patent and share your thoughts here. It is nice that you have settled the issue VLF or PI, at least to my satisfaction. Very nice compliment to Dimitar I think coming from you. I can tell you, he stands behind his detector and is never to busy to talk with anyone. Very down to earth guy. Look forward to more reports on the detector.