Can someone please explain Reverse Discrimination.

[thump7]

I have never read anywhere about how to actually discriminate backwards. But I keep reading about it, especially when I read older threads. Is it just a matter of having disc 1 set a little higher than disc 2? Or is there more to it. Also what is the real advantage to reverse discrimination?

 

[shooter]

Yes I can used it for years,I don't know what detector you are using now but it was designed to be used with the older TR detectors transmit receive type detector it's simple process but it's extremely effective I use it for years when I use my Fisher 555-D detector. Ground mineral compensation was more difficult and you had to keep the TR machines in tune for any depth, by this meaning they had been retuned with the toggle switch which also change the mode from all metals to discrimination. While searching in discrimination mode when you come upon target a lot of times you couldn't detect close to the ground which at that time you didn't have a FAST GRAB mode F-75, so you would have to hit the toggle to bring it back into tune. When you came across a target you would move the coil down to the ground and center it over the target, which would have given a loud audio interference threshold sound, you would center the coil over the target and press and hold the toggle in the discrimination setting then slowly drag coil off the spot if the threshold got louder it was junk if the threshold disappeared and went silent that men it was a good target and time to dig. It was very accurate specially would discrimination being set at five to keep Nickles and gold rings in found hundreds of rings that setting TR machine. I hope this helped you out any more info on reverse discrimination I have a small construction paper that I used to keep semi your email address in the p.m. and email to.

 

[shooter]

Sorry if some parts of this post seems like i'm an idiot writting this I just installed Dragon Speaking 12 and i'm just getting the hang of it. Have to double check more.

 

[thump7]

I own a 1265x and hopefully I can buy a 555 fisher from my neighbor, I'm not sure if it is a 555-D, I didn't take the time to see more than "555 vlf" writen on the 8" coil and couldn't see any specifics writen on the machine.
I got most of what you were trying to say and it helps a lot with what I am trying to understand.
There are not very many people on the forums that still know how to run some of these old yet very effective machines - at least that I am aware of.
I came across a few of your posts while looking for information on the old 555 fisher, and your knowledge about it is invaluable to me, because I could find hardly anything else writen about it.
Thanks for your reply, if I have any more questions I will be sure to send you my e-mail.

 

[shooter]

Thanks for the comment, its a super machine with great capabilities, the machines has no super functions like the F-75 series or any other digital computerized system,It reads what it sees, totally up to you to understand what it's telling you.Once you learn the basics 555-D your limits are your own intelligence, you must determine what the non-digital system is trying to tell you ground balance, "threshold tone" is the basics machines function for stability, this system will detect deep targets with out and audible sound, but you will see a fluctuation in the meter needle to indicate presence of deep level, most of my in the water rings and jewelry I recovered from needle fluctuation with no audio. You must maintain audio tone to hear and see the fluctuations as minute as they are, remember again there is no bells and whistles this type of machine. I can give you all the hints you want but you have to actually use a TR discriminator detector to learn exactly What it's telling you. Digital machines are far more advanced but basics has a lot to be said it's upbeat and dig machine must determine what it's telling the newer models of digital computerized detectors have so many variables makes the operator question exactly what it's telling him, TR detector only states was is there.

 

[JB(MS)]

Reverse discrimination was only applicable to detectors that had a VLF all metal mode and a TR disc mode. Richard Hirschi at Whites discovered that a target could be classified as either good, above your disc setting, or bad, below your disc setting and coined the phrase "reverse discrimination" to describe the technique. The VLF mode was a lot deeper than the TR mode, and by using reverse discrimination you could recover desirable targets too deep for the TR mode to detect. Reverse discrimination consisted of searching in all metal mode until you got a signal, then pinpoint and set coil on the ground over the target, switch to TR dsic mode and with the coil still on the ground push the retune button to retune the threshold. Slowly slide the coil away from the target, if the threshold increased it was something below your discrimination setting. If the threshold decreased it was something above your disc setting. If there was no change in the threshold it was something too deep for the detector to classify.