transmitter vlf

[Dave J.]

This conversation which started in nonsense, isn't getting any closer to sense.

All this concern about "transmitter vlf" (title of the thread) with almost no concern about the receiver.

Ordinary metal detectors have VLF transmitters which are designed by real engineers to actually transmit! Not this NE555 or calculator-on-a-stick malarkey.

And, real metal detectors have real receivers. That really work. The most sensitive units can detect a VLF energy perturbation about the same magnitude as the energy of one red wavelength photon.

You heard me right. Multiply voltage sensitivity by the equivalent current sensitivity and by the response time, and if you have the necessary scientific and engineering knowledge, you can verify it for yourself. One red photon.

Try that with your swivelly thingy. Holding it in your hand in a perfectly neutral (laboratory perfect, non-field) environment, its directional sensitivity is limited by hand tremor, as any time spent following dowsing forum posts will confirm. It ain't the rod, it's the hand holding it and therefore the brain that's behind the hand.

Anyone who's dealt with the challenge of making sensitive electronic measurements where something in the signal path had to be hand-held knows the problem: until you eliminate the ability of the hand to change the signal, you're schitt outa luck. It ain't happnin'. Hand tremor has too much energy.

I am not saying that dowsing is entirely bogus. What I am saying is that the electrical theories behind LRL'ing are entirely bogus, and provably so. In fact it's that provability that has LRL fans so parsed arf with folks like Carl and the A.R. and even with me. In the case of Carl and myself, VLF electronics are our livelihood, for which we get paid only because the stuff we design actually works and nobody, not even the LRL dependabillies, dispute that it works! In the VLF detection industry there are lots of arguments about who's got the best stuff for what purpose and whose advertising department stretches the truth a hair too much, but assertions that the stuff is bogus from the get-go are entirely absent no matter how stiff the competition.

To simplify the foregoing argument a bit: no matter how much I dislike a competitor in the metal detection business, I can't say that metal detection is all a fraud. However I can say that all LRL's are fraudulent, because they are not competing for targets to be located, they don't locate buried targets at all! They only do wallet biopsies.

--Dave J.

[WM6]

Originally Posted by Dave J.

However I can say that all LRL's are fraudulent, because they are not competing for targets to be located, they don't locate buried targets at all!

They only do wallet biopsies.

Thanks Dave, I agree with you.

But you know that we enter here religious sphere and there is no acceptable arguments that can replace someone beliefs. Beliefs wants to be satisfied.

So we are here to meet those unchanged LRL demand. Practically for free, instead of possible "wallet biopsies LRL".

I can guarantee that all my, J_Ps and oter members construction proposed here, worked as well and even better, than all those extremely expensive mineoros, rangertells, H3tecs, bionics etc.. Verifiable.

And all those practically for free. One needs some cheap parts and some of his time only and get funny and by the way educative things which can do those "something".

[Seden]

Since JPlayer pointed out the realities of the article you posted, I think I would use a low noise design of a Q-Multiplier antenna circuit. They work great. Google it.

Randy

[Dave J.]

Yeah, but Randy, there some problems with your suggestion.

1. You suggested doing some real engineering-- low noise, active high Q circuit. LRL'ers are lousy circuit engineers, because after all, if they had the knowledge and skills to design such a thing, they wouldn't be wasting their time on LRL's.

2. Which leads to the opposite problem: the phrase "low noise Q multiplier" supplies great raw material for a pseudoscience word salad, and in the world of LRL's, things are whatever your fairy tale fancies them to be, what they really are is no more relevant to LRL's than the ARRL Handbook is to Alice in Wonderland. Simply applying the words to something that isn't a low noise Q multiplier circumvents the whole messy problem of how to actually build a low noise Q multiplier.

3. But suppose that a person were to actually build a real low noise Q multiplier. Now that you've got it, what does it have to do with finding buried treasures? Nothing, unless it's part of real geophysical apparatus and therefore not in the "LRL" category.

[For what it's worth, the last time I built an LC circuit Q multiplier was 50 years ago. They're not nearly as magic as they might seem at first glance, that's why I've not used them since.]

--Dave J.

[Seden]

Dave,

Your point is well taken. I guess I had pretty good results with the Q multiplier I built. Maybe because it was for the 1750 meter band.

I am not an LRL guy but thought I would help the guy out with a real circuit. By the way I've been a Amatuer Radio op starting in 1970 as WN7RUJ. Ah the days of crystal controlled 75 watt transmitters. In 78' I became WD6ELU and have an Advanced Class license.

But I find it interesting just to see what these experimenters are playing with. I own quite a bit of true Geophysical equipment and sure works for me!

For placer gold my most useful is a Geometrics Proton Mag. and hard rock it's the Scintillator Gamma Det. hands down. That Scintillator is so accurate and easy to use I feel like it is a true LRL. For the desert sands it's a mercury sniffer followed up with a wet assay. Lot's of fun to be sure. And finding bedrock it's a seismic. Never have used the 4 terminal Resistivity as I never finished making up the cables (Vibrosound unit).

Who knows, maybe someone will stumble onto something that works.

Randy

[WM6]

Originally Posted by jack

hi to all
I need a transmitter vlf 0-30k With relatively high.I've searched the internet but did not.
Please help me for a transmitter vlf.
with respect
jack

What mean "With relatively high"?

[Dave J.]

Originally Posted by Seden

Dave, Your point is well taken. I guess I had pretty good results with the Q multiplier I built. Maybe because it was for the 1750 meter band. Randy

1750 meter band? No kidding! I was very active in LWCA late 80's - early 90's, had both a fixed and a portable beacon, built receivers, lots of technical articles published in club newsletters.

One article was about one of my projects that I called "fake active whip"-- a mobile clip-on CB antenna with a shunt tuning capacitor and a series resonant inductor going into a passive impedance matching network. As sensitive as most active whips, but of course was narrowband, either an advantage or disadvantage depending on your perspective. .....Funny, one of the other members (a rabid active whip fan) protested my calling it a "fake active whip".

It didn't occur to me that I coulda turned the thing horizontal, stuck a swivel handle on it, called it a treasure finder, and sold it for $5,000 a pop to gullibillies.

* * * * *

Down in the ULF band during that same era, I also played around with a portable earth current communications system running at 5 and 10 Hz straddling the fundamental Schumann resonance. The 5 Hz signal was doubled in the receiver to synchronously demodulate the 10 Hz signal polarity which was BPSK encoded.

--Dave J.

[Seden]

That sounds very interesting. What kind of range did it have? Did you ever publish anything on it?

I was using Single Sideband with a couple guys in the San Fernando Valley. One in Studio City,the other in Granada Hills and myself in Simi Valley. We were on every Saturday morning for about 10 years. We also played with Amtor using the good ol' Pakratt version 1.o. I was ELU,then there was Dave Curry of Curry Communications who is PLI and Charles Faulker FPV,all done on 183.5KC. I had a 50' vertical with a 5/8 wave CB antenna with a wire around the ground plane and all shorted to the vertical element making one heck of a Capacitive hat. Did I stick with one watt? I may have run more (like 40 watts RMS). I figured if the FCC wasn't going to hold their end of the bargain with the light dimmers and other junk, I'd have to compensate for it.

Randy

[Dave J.]

I ran the dahdidit didahdahdah beacon from Los Banos, CA for several years. Approx. 35 foot max height whip vertical on the top of the house, no top hat, strictly 1 watt, I calculated radiated power at about 12 microwatts. Was often heard in the Bay Area, occasionally in the Fresno area, and occasionally by Mike Mideke who was I think something like 200 miles away out in the southern coast range wilderness with very good receiving equipment. Inasmuch as I don't know Morse code, never attempted manually keyed communication, just fixed ident beacons.

Designed from scratch and built a simple little 1750 meter band SSB receiver that fit in the palm of your hand, with as I recall about 100 Hz wide 600 Hz tone filter. Of course the antenna wouldn't fit in the palm of your hand, that's what the "fake active whip" was for although the receiver was designed to match 50 ohms so it could be used with almost any antenna. At a LOWFER convention near Santa Cruz we raced my receiver against a fancy commercial rig with a few custom enhancements that one of the other guys had, and it was a tossup which was best.

One of the funnier aspects of that convention was that out of about 35 club member attendees (there were about 40 more as guests), five of us were some combination of Dave/David Johnson/Johnston. Often got a bit confusing! although most of us sorta knew who some of the others were through club newsletters and personal communication. (This was all before the Web.)

Was interested in caving communications for a while and designed and built a crude proof-of-concept prototype hand-held portable 1750 meter band voice SSB transmitter and receiver system. Didn't work very well but it was a fun experiment.

--Dave J.