Experimenting with Half Bridge Bi-Polar Transmitters

[Carl-NC]

I remember he wrote something like "better than whites patent #" and the TDI I don't think has any patents.

Well here's the quote so

"This system is better than US9285496B1 Patent of CARL / Less capacitance, lower noise, best heat dissipation, faster delays, etc ...."

There is some fairness to that claim. My THS design used a full H-bridge so it was not optimized for pure speed. With some effort the AQ can sample less than 5us. Lower noise or lower power, I'm not so sure. Keep in mind that I had achieved a working prototype and had made no effort to optimize anything. There was still a long way to go. But what I had, boy did it look good.

This poster looks relevant http://zonge.com/wp-content/uploads/...TEMposterA.pdf

Yes, this is standard half-sine, what Tony Barringer pioneered. My god, look at that transmitter and the size of the coil cables.

[6666]

Great work Altra.
Just wondering if we were to use a shielded coil which I assume we need
where would you attach the shield ? thanks.

[Carl-NC]

Just wondering if we were to use a shielded coil which I assume we need
where would you attach the shield ? thanks.

RX ground

[green]

Was thinking the best Tx profile(same peak current at Tx off)for highest Rx signal is constant current for at least three target time constants. Is there some reason THS gives a higher Rx signal with same peak current at Tx off?

[Carl-NC]

Was thinking the best Tx profile(same peak current at Tx off)for highest Rx signal is constant current for at least three target time constants. Is there some reason THS gives a higher Rx signal with same peak current at Tx off?

Without scratching out some math, I can't say that THS gives a higher Rx signal for the same current. But what it does give you is both a full VLF response and a PI response at the same time. There are some tricks you can do with that to produce pretty impressive results.

[Ferric Toes]

Without scratching out some math, I can't say that THS gives a higher Rx signal for the same current. But what it does give you is both a full VLF response and a PI response at the same time. There are some tricks you can do with that to produce pretty impressive results.

I'm not sure about the truncated half sine, but with ordinary half sine the rate of change of TX current increases as it approaches zero whereas a normal damped Pi it slows up toward the end. This would appear to make half sine better, particularly for fast decay targets.

Eric.

[eclipse]

Another question. Tinkerer has layed out TEM method in his posts regarding Tinkerer Project. It produces half sine pulse not too different from THS except for being unipolar. My guestion - is there any significant difference except for the bipolar and the truncation stuff.

[ivconic]

Few bold claims keep repeating here.
Pure text. Not interesting. Most of the time i don't have slightest clue what about you people talking here.
Especially when using many wild abbreviations.
Would be good to see some video showing at least something from such claims.
Carl you do not leave the impression of a person who makes questionable statements lightly, so i have almost none doubts in your claims.
But to make this topic more interesting and colorful; don't you think is fair to give more insight to us here, about what you stated few times?
Logically; no one would expect disclosure and details. But short demonstration video would do quite good.
If you say something like: "I achieved it, it beats the crap out of...", than is fair to show at least something on video.
I guess that's why Geotech forum slowly slipped into pretty annoying form.
On one side there are some people constantly asking simpleminded questions and wasting lot of time on basic elementary stuff and
on another side there are few totally nerdy "mathematician-masturbants" who will drain your last drops of patience with terrible bedlam of nonsense maths, abbreviations and
mostly dealing with simulations, overall useless abstractions.
There is no "middle side" on forum anymore.

[kt315]

we discussed on half bridge. this is Dave's J. matter. maybe good maybe old. but what typo you want to do - VLF or PI detector with your half bridge?
do you want to repeat Dave's work from start to finish?
https://www.geotech1.com/forums/show...Feb-2016/page9

[Carl-NC]

I'm not sure about the truncated half sine, but with ordinary half sine the rate of change of TX current increases as it approaches zero whereas a normal damped Pi it slows up toward the end. This would appear to make half sine better, particularly for fast decay targets.

True, and you can alter the slope at turn-off by changing the "frequency" of the half-sine pulse.

[Carl-NC]

Another question. Tinkerer has layed out TEM method in his posts regarding Tinkerer Project. It produces half sine pulse not too different from THS except for being unipolar. My guestion - is there any significant difference except for the bipolar and the truncation stuff.

As I recall, TEM has a quarter-sine turn-on and quarter-sine turn-off with constant current in between. It has benefits of a fast turn-off slew and energy recycling.

The benefit of HS and THS is you get a true sine response region, plus a PI response region. So you can do a true hybrid VLF+PI design. And multifrequency if you like.

[Carl-NC]

But to make this topic more interesting and colorful; don't you think is fair to give more insight to us here, about what you stated few times?
Logically; no one would expect disclosure and details. But short demonstration video would do quite good.
If you say something like: "I achieved it, it beats the crap out of...", than is fair to show at least something on video.

Everything I did with THS was done at White's 7 years ago. I left it all there and have not worked on it since, so I have nothing to show. And I was not going to work on it as long as White's is in business, plus I really don't have the time. Maybe that will change.

[ivconic]

I understand.

[Tinkerer]

Another question. Tinkerer has layed out TEM method in his posts regarding Tinkerer Project. It produces half sine pulse not too different from THS except for being unipolar. My guestion - is there any significant difference except for the bipolar and the truncation stuff.

The TEM method has a lot of good things worth wile to tinker with.

It produces roughly 2 times more signal amplitude for a fraction of the power consumption.

There are many other advantages.

I am going to open a new thread for ideas to tinker with.

[6666]

The TEM method has a lot of good things worth wile to tinker with.

It produces roughly 2 times more signal amplitude for a fraction of the power consumption.

There are many other advantages.

I am going to open a new thread for ideas to tinker with.

Sounds good