Hey Tom what is the most critical weakness of the F-75 ltd/se

You have found in your use of it.....Not talking about the mechanical aspect or physical layout ....Just performance wise what is the 1 thing that keeps popping up in your mind that you would like to see changed/enhanced.....

electrical interference ...Target I.D. instability..more responsive to certain target's...more accurate iron I.D....anything you care to share?

There's always something that lingers in the back of my mind on certain unit's that I really enjoy that I wish could be changed.....

Keith

EMI ................ HANDS DOWN!

If you ever have the opportunity to take the F75 LTD/SE into a tempest booth (RF shielded room)........... its performance is stunning. If I could get it to perform this way in the real world....... the end resultant would be phenemonenal.

Another thing you can do is ....... find a place far out in the middle of the countryside...... that presents very little EMI........ invoke the 'cl' mode... and air-test a Type-1 U.S. $1 gold coin. Stunned......... you will be.

Indeed at least in my neck of the woods try to get any depth out of a F series and you better bring the Excedrin.
T-2 also the same...Never did buy the explanation of its picking up every little speck of content of the ground but imagine it adds to it...Just love the noise cancel of an Explorer as let it run thru the channels and you are good to go and leave the Excedrin in the car....

Most of us that own that machine already knew that would be Toms answer, and I think you did too Keith.

Not being a engineer and the following statement will probably prove it.................can metal tape for EMI reduction be applied to the control housing and the upper 2/3 portion of the coil wire (up to the point of not being picked up by the coil)?

The F75 control housing is painted internally with graphite-loaded paint, which is electrically connected to the circuit board. The main source of E-M pickup is the search coil, which is basically a radio antenna, shielded to keep out most of the electrical noise, but allow magnetic signals through. Hence why the 5 inch DD coil is 'quieter', it's a less effective antenna.(it has a smaller area, but more turns of wire, but the net effect is that it is 'smaller').

Pim, even though the F75 is shielded, it appears that in many instances, the shielding is insufficent. Maybe it needs more......in both the coil & control housing. If the 3M tape wasn't so darned expensive, I would try my theory out on my Omega....which is also highly susceptible to EMI.

It does have its weak points. The wire connection is to the rear of the case. The front panel makes its connection to the rear in a mechanical way when the case is screwed together. This may be a weak point. I'm not sure if the front panel is joined to the circuitboard in any other way. The other weak point is the way the wire is 'joined' to the screening paint. In my machine, at least, the wire is stripped bare on the last 10mm, the strands fanned out and the wire 'fixed' in place with sticky-tape. The bare wire is then painted over along with the rest of the case.

90% of my hunting is in the middle of large cities (San Francisco, Oakland, San Jose, etc) and I don't find the Omega to be as susceptible to EMI as the F75 LTD, at least not with the 11" DD (I recall it was more susceptible to EMI with the stock 10" coil).

I've been shut down before by EMI on my F75, but knock on wood, it hasn't happened on the O8 yet. I do agree that they really need to do whatever it takes to make EMI a more passive issue. Most of my friends that hunt with White's or Minelabs almost never complain about EMI. That doesn't mean they don't get affected by it, but at least they don't have to listen to it

BTW how expensive is that 3M shielding tape and how much comes in a roll? If it's a lengthy roll, perhaps a group buy is in order.

Not enough shielding and/or static build-up can cause weird operational problems that could be interpreted as EMI.

Thanks Tom!!!!

I figured it was the EMI......

As smooth as they have got the Gold Bug....Wonder if they can get that to carry over to a new machine to replace the F-75?

Keith

Gold Bug is not as 'boosted' as the F75.... for one.