Frequency discriminator and all-electronic receiver

[Mike(Mont)]

A little catch-up here. Had some problems with the Contraption a while back.Wasn't locking on the target and I assumed it was due to solar magnetic interference. Then the Tx just quit working. I went through all the connections, etc. trying to trace down the problem. It was a power amplifier that went bad. I should have put a heat sink on it but it lasted several years. In the process I found one channel on the frequency generator had erratic voltage, bouncing all over the place but mostly millivolts so I replace the the unit. In my search I found a freneator that looked very similar to what I had. It was a rife machine and the guy has designed his own waveform. Think hje called it the H-bomb square wave. NOt making any claims about it but because I haven't had it out in the field yet.

[Mike(Mont)]

I seem to be making some progress with the Contraption. I adjusted a high pass filter on the receiver so it detects lower frequencies better. Also I have been working with different frequencies. I was reading an old manual said higher frequencies discriminate faster. To me that means during times when interference is off and on, the target locks on easier. Pinpointing is not perfect, maybe just need to fine tune the frequency a bit, I don't know. But one main thing I did was change the wave form to triangle. I was reading some info at gdi-detectors.com about how they measure the ground resistance and decide which waveform to use. Normally this area is very dry ground but melting snow now and it does affect things. Even though we are very near solar maximum, for the most part it has not had much effect on my testing. Locating conditions have been good lately. Just to repeat, wet, mineralized ground does not like the square wave. The signal does not lock-on very well. I read somewhere square wave is strongest, sine wave is 1/2 strength, triangle wave is 1/3 strength. Before I retuned the high pass filter the triangle wave was very weak signal, now it is quite a bit better.

On another note, reading the LRL reports page on geotech1.com Dell Winders used a magnet inside his Weight Chek belt receiver for the L-rods. Said something like it smooths out the signal. To “smooth distortions of the magnetic field, providing more definable responses from the receiver rods.” So easy enough to try this on whatever device you are using. I know when I walk through the test target area my body field acts like a degausser so I suspect the magnet does the same thing. I've seen map dowsers wipe down the map with a large magnet before dowsing.

[Geo]

AGR stands for Advanced Geophysical Receiver. Accurate Locators (out of business since the owner died) sold them for like $10,000. They were for large mineral deposits/lodes and only had about 100 feet (30M) range. Somewhere I have some info on it. I'll look for it.

Hello Mike. Did you look it for????

[Mike(Mont)]

I found it a while back but my printer was running out of ink so most pages are illegible. Basically you take the AM radio station in kHz and multiply by the frequency factor. The answer is in kHz and this is what you tune the receiver to. AS I recall fist-sized targets and larger from maximum 100 meters. He said it was a super-het receiver. Also said if you don't have a good AM station you can use the naval VLF station and tune directly to that frequency. He gives no details on receiver construction.