Need help

[Kirk]

Need some help. I have read the manual going on 3 times now and have used the machine on 4 occasions so far. I have been using the DE mode to hunt some sites that are very trashy. My questions are:

-What is disc setting of 6? in the DE mode I have been setting the Disc as high as 60 to do some coinshooting in very trashy areas

-I am getting all kinds of noise when swinging the coil-is my sensitivity set too high, seems like when I back it down to 30 or 40 I hear less noise but still there

-TID numbers are jumping all over the place as I swing the coil, along with some of the weak signals- is this normal?


-even with the disc set at 60 I sometimes get a solid signal both visually and audio say at 54-shouldn't this be nulled out/

Thanks for any insights.

 

[wallyblackburn]

Kirk:

One thing that is not made clear in the manual is that another stage of amplification (a pre-amp) is added when you set Disc below 5 or above 20. This pre-amp is also added in all settings when using JE mode. The pre-amp greatly increases the sensitivity of the F75, causing it to be unstable in all but the cleanest of areas (unless you really crank Sens down - see below).

Try this: Do a factory reset (hold red menu button and push trigger forward during power-up). Then, instead of changing Disc from the default of 10, go through and Notch out all of the ranges you don't want to see - even all of them up to 60 if you want. This effectively blocks the unwanted targets, but does not kick in the pre-amp.

You may find that you can even kick the Sens up to 70 or more without the pre-amp.

An alternative would be to drastically lower the Sens (down to 30 or so), but I think the pre-amp changes the sounds of targets and the whole "feel" of the detector. OTOH, if you ever want to run it hot, you'll use JE or some other settings with pre-amp, so you might want to get used to it now.

Hope this helps,
Wally

 

[chuck ky]

have never used or seen in use a f-75 but will venture a guess on this one. i use a sovereign. on the sovereign i have set it at full disc. and dug mercury dimes that only read in the 130's instead of the normal 180. this could be what is happening. the only other thing would be that 60 on the disc. scale doesn't mean the same as 60 on the i.d.

 

[Mark in NC]

Wally has some good points in his response below, also the F-75 sees EVERYTHING in the ground when you sweep the coil. If you're getting no noise when it's stationary, but hearing stuff when moving, chances are your spot may be loaded with tiny conductors. One of my favorite coin hunting setups is Disc at 6, sensitivity as high as conditions allow, De process mode, and 4h audio.

I'm not sure on the 54 ID when disc up to 60...

 

[Idaho-Marke]

You write: "Try this: Do a factory reset (hold red menu button and push trigger forward during power-up). Then, instead of changing Disc from the default of 10, go through and Notch out all of the ranges you don't want to see - even all of them up to 60 if you want. This effectively blocks the unwanted targets, but does not kick in the pre-amp.

You may find that you can even kick the Sens up to 70 or more without the pre-amp.

Hi Wally:

This is really news to me. I've never had a machine with notching before. What I read in your suggestion is that you can notch in/out many different areas instead of just one. I understand why you are doing it, but I don't know how to go through the motions to actually do it. The manual doesn't explain it.

Could you perhaps explain the motions to notch out a few different areas for those of use who are new to this.

Thx so much.

Marke

 

[Jeb NWR]

In trashy areas use ... De or Pf mode. Try Low sensitivity such as 45,as too much sensetivity in a trashy area will Smother your Audio output with Garbled Noise.
Go fora low Discrim 6. and LISTEN for the GOOD signal that will come though the trash when it does . Ignore the low Burps of Iron .Hopefully, you WILL recognize a good signal when you hear it . Whatever you do , I suggest you do not use Massive amounts of Discrim OR ELSE you will lose Gold rings and possibly some thin silver and Platinum. Using Massive amounts of discrimination also cuts your depth Right down to.Try using only "2 tone" too, as using 4 tones will give lots of squeeks and noises that will just confuse you. Hope this helps .

 

[wallyblackburn]

It's one of those things that would be a lot easier to show than tell, but I'll give it a try....

Oh wait - I looked through the manual and it actually is in there. It takes up all of page 16.

HH,
Wally