Quote:
Originally Posted by WM6
Thanks J_P, for good explanation.
One remark: I intentionally did not gave high output power transmitter solutions to stay inside authorities regulations limits regarding EMI disturbances in RF spectrum.
At the same time, using low power TX, we can, with proper designed RX, and under proper circumstances, even sense changes in wave polarisation on short distances, which is very important to distinguish between different source and direction of received wave mess. With even slight higher power this is not possible to achieve at short distances.
RX problems and solutions we will discuss once in next year.
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It is important to understand that high power is not necessary to make VLF penetrate deep into the ground.
The geologists are using low power portable transmitters to measure maybe more than 40 meters deep into the ground.
They use less power than the limit for most countries.
Most people do not bury treasures 40 meters deep. Most treasures are less than 2-3 meters deep.
It is easy to penetrate to 2-3 meters with very low power VLF.
Most people who experiment with LRLs are using less power than a metal detector will use at similar VLF frequencies.
I read where many LRL experimenters say that too much power will destroy their detection.
In the case of Mineoro, the reports from the factory and users close to the factory say that if you put the power from moving a metal detector coil over a buried treasure site, you will destroy the detection for that treasure for several days.
Then you must wait a few days until the signal will return before you can locate the treasure.
The biggest problem with illegally transmitting high power VLF is you could be interfering with the submarine communication signals from large countries like Russia, USA, Canada, and many others around the world. If these countries have problems from interference, then they will find your location by using their radio direction locators.
Then they will complain to the state department for your country.
Then there is a very good chance some government officials will come to your home to confiscate your equipment and impose fines and imprisonment to you.
You must remember, these VLF signals can travel very long distances with not much power, and they can penetrate the ground and ocean water very easily.
Especially the lower frequencies. This is why submarines use VLF for secret communications.
Russia is known to operate VLF transmitters which change to different un-published frequencies without announcing when they change frequencies.
I would not want to be broadcasting a high power VLF signal that interferes with their secret military communications.
Best wishes,
J_P