F75 Tips: Lower your sensitivity and rub the ground!

I discovered a neat tip to share with others while detecting with your F75. Because this guy is SO sensitive, if you are in an area with an increased amount of interference (indicated by high-tone chatter), lower your sensitivity. I've found this lowers the volume of the high-tone chatter and allows you to hear the real high-tones more clearly as they will remain at a somewhat similar volume to the higher sensitivity setting. I went over an area with a high sens and found nothing, then went over the same area with a lower sensitivity, and found a bunch of coins including a stack of 3 silver dimes. The previous high-volume, high-tone chatter hid the signals where as the low-volume, high-tone chatter did not.

Also, I've noticed a much clearer distinction between the high-tone chatter due to interference and real signals if I'm touching / rubbing the ground when swinging. It takes a bit more effort because you have to deal with the friction of swinging with your coil touching / rubbing the ground, but you'll find the more plentiful and clear targets worth the extra elbow grease.

The lower sen will stop most of the noisy, all so if you use a small coil and in DE mode will help. But where you can run sen, as high as you can for more depth. It is easier with the small coil to stop the noisy because the coil sees less.

If the area you are hunting is producing some interference on the F-75/T-2 and requires you to (say..... for example) drop the Sens to '62'....,,,,,,, bringing the detector to a ""just barely perfectly stable"" (threshold/redline) condition; This is where maximum performance is ascertained. Raising the Sens above '62' (in this example) will only increase human fatigue factor via EM interference...... yet the max depth performance will NOT increase with higher Sens settings. In other words; If max Sens stability is ascertained at Sens setting of '62'....... you will gain no more depth (or overall performance) by increasing the Sensitivity. IF, IF, IF the area allows higher Sens settings and EMI stability is not infringed.... critical depth gains will ensue. A Sens setting of... say; '62' may detect a dime at 8.75"....... but a Sens setting of '92' may detect a dime at 10.75" but ONLY IF the higher Sens setting does not induce EMI. Raising Disc (a last resort) will also reduce EMI in many cases....but all rules of physics still apply; The local area EM interference will still restrict the detectors depth capabilities/performance to 8.75" dimes. ... In situations of EMI..... I switch over to a 11.25" dime capable CZ (assuming iron trash is not too excessive). Old coins (silver or otherwise) are generally, quite deep (( Understatement )). If you hunt a parcel of land with a 8.75" dime capable unit; chances are; SO DID EVERYBODY ELSE! When a detector can exceed 9"..... you can (most probably) safely say that you are hunting 'virgin' ground,,,,,,,,,...... where no other man has gone before.

Sincerely,

Tom

For clarification on your comment Tom ..

1. If the F75 is still getting EMI related chatter at a sensitivity of '29', I would probably do better to run through the area with a CZ as long as it's not full of iron trash?
2. What is the technical reason for why the CZ does well in a high EMI area and the F75 does not?
3. Will the coil size (6.25" vs 11") or type (DD vs Concentric vs Elliptical) affect my ability to detect when dealing with EMI on the F75?

Different detectors respond differently to EMI for two primary purposes. First; The operating Freq of Detector 'A' may be LESS affected by a certain type of EMI that has a greater EMI induced condition on Detector 'B'. Secondly; Multi-Freq detectors (in general) can handle EMI much better. Ckt design & shielding also play a role.

...... Coils/Coil-sizes can make EMI-response differences,,, a trial-and-error resultant required.

I have found the CZ platform to be one of the most EMI resistant capable units compared to all others.

Tom

If you were me and had only an F75 (and an F2) yet loved to hunt mainly for coins in urban areas, would you invest in a 3D or gut it out and suffer through the noise of the F75?

You have already invested in the F-75. Put it in 4-tone mode and dig the top two tones..... and mitigate EMI as much as possible. The F-75 is a VERY good coin hunter.