Excalibur 2 False Signals

[Tony in FL]

I have noticed that my Excalibur II with 10 inch coil can occasionally produce false signals where there is wave action present in salt water. These false signals are typically quick chirps and/or changes to threshold. When I reduce sensitivity it does help out but even at the lowest sensitivity level (and when using auto) the false signals are sometimes still noticeable. While the machine is still usable under these conditions it is a hassle as I sometimes feel the need to recheck a signal to determine if it is a false signal or not. This behavior is also most prevalent when in deeper water i.e. a few feet or more.

I have tried with and without a coil cover as well as securing my coil wire with Velcro in a few spots. On some beaches, particular in Tampa Bay or in areas protected from wave action my Excalibur is very stable at 12:00 sensitivity going from dry sand, to wet sand, to low water, to waist/chest high water. However once I am at a beach where wave action is noticeable, such as Clearwater Beach, then I start to get false signals. Sometimes it is only occasional and other times it is more persistent. The rate of false signals seems to change even on the same beach perhaps due to variations in wave intensity

Is this sort of falsing normal behavior for the Excal 2 with 10 inch coil? And if so I wonder if it would be lessened if I were to use the Excalibur II with the smaller coil?

 

[Bling]

i NEVER run in auto! always manual! just keep backing it down until it quits falsing and it will be good to go! on some beach's iv got to back it all they way to 2 Oclock to get it stable but have little or no loss in depth.

 

[goodmore]

Do what Bling said. Back it down until you reach a limit of falsing you can live with. Some is very normal. My Excal does it. So do the Sovereigns.

 

[Tony in FL]

Thanks for the feedback. Note that I typically don't use AUTO either. It is just something I tried to eliminate falsing in rough water and it did not seem to work.

So it sounds like in rough salt water some falsing is par for the course? At some beaches I can switch sensitivity to the absolute minimum, but there is still some occasional quick chirps and/or changes to threshold that seem to be related to waves action. I would have expected to be able to completely eliminate this at the minimum sensitivity level as at many calmer beaches I run at 12:00 - 1:00 with almost no falsing.

 

[OldBeechnut]

Old Blue does it also when the waves are coming in



http://www.youtube.com/watch?v=PJdlYjv06Kg

 

[Florida Keys Pirate]

Mine falses in the waves also. No adjustment fixes it.

 

[davespen]

Salt water is conductive... As with any conductive substance, adding more of it will have an effect on an electromagnetic field. In other words, you don't want to tune out the sensitivity to the point the waves will not affect the proper operation of the detector. You can deal with it by changing your search patterns and detecting habits... Try searching perpendicular to the beach with your coil swing parallel to the beach....you will achieve some stability as the coil is swept through a consistent depth of water .... do the same on the beach or at the transition line since the salt water content of the sand changes as you move away from the water (conductivity of the substrate changes also) which affects the machine... you hear the difference in the falsing. When in the water and I see a swell coming, I simply place the coil on the bottom already anticipating the falsing and continue on once the wave has passed. Not sure if you've read any of Clive's books regarding the Excal, but if not, I recommend them highly. These machines are particularly sensitive to changing water depths (salt water) for the reason described above). That's why they will false as you attempt to sweep across a trough vice keeping the detector at a steady depth working the length of the trough. Sorry for the technical explanation, but sometimes it helps to understand that an apparent problem may simply be an indication the machine is working properly.

Regards,
Dave

 

[RichW]

I've got 2 Excal II's Tony. Both have 8" coils. My oldest seldom ever falses even in very rough water. I can run the sensitivity very high and it's still smooth and stable and it goes deep. My newest machine is not like the 1st. It does exactly what you are describing. Even with the sensitivity at a very low setting it falses a lot in wave action. In calmer water and on the beach it does just fine. I have no idea why my older Excal II is so much more stable but the newest machine is now my back up. Also, my cousin had an Excal 1000. The thing drove him nuts in water that had any wave action. After his machine was out of warranty he put an 8" Sunray coil on it. Now it's like a completely different machine. His machine is now just as stable in rough water as my 1st Excal II. Might even be more stable and he gets incredible depth with his. So, that's my experience. I have no explanation for what's going on and the differences between Excals.

 

[OldBeechnut]

davespen, do you thing this will help. copper EMI sheilding

 

[davespen]

Hi Joe,

Great job with the shielding! Your copper shielding will certainly address interference from nearby power lines, transformers, etc. Did you apply shielding to the underside of the housing? Does the shielding have a plastic coating (I'm sure it does). Be sure to treat the edges to prevent corrosion from the exposed copper where the shielding was trimmed.

I never heard back from you regarding that fantastic decal you designed. Any luck having it printed?

Dave

 

[OldBeechnut]

Thanks Dave, did one excal with the copper shielding..the other has no metal on it at all other then one SS nut/bolt for the armrest.....and the electronics..just alittle test for the summer. Also did a couple decals, wanted to see how they hold up to the sun, n salt ...cost about 8 dollars each to print..one is a dark and the other is lite...will let you know, and next fall I will hook you up with a custom vinyl decal..............if they work out....

 

[Neil]

Salt water is conductive... As with any conductive substance, adding more of it will have an effect on an electromagnetic field. In other words, you don't want to tune out the sensitivity to the point the waves will not affect the proper operation of the detector. You can deal with it by changing your search patterns and detecting habits... Try searching perpendicular to the beach with your coil swing parallel to the beach....you will achieve some stability as the coil is swept through a consistent depth of water .... do the same on the beach or at the transition line since the salt water content of the sand changes as you move away from the water (conductivity of the substrate changes also) which affects the machine... you hear the difference in the falsing. When in the water and I see a swell coming, I simply place the coil on the bottom already anticipating the falsing and continue on once the wave has passed. Not sure if you've read any of Clive's books regarding the Excal, but if not, I recommend them highly. These machines are particularly sensitive to changing water depths (salt water) for the reason described above). That's why they will false as you attempt to sweep across a trough vice keeping the detector at a steady depth working the length of the trough. Sorry for the technical explanation, but sometimes it helps to understand that an apparent problem may simply be an indication the machine is working properly.

Regards,
Dave

"sometimes it helps to understand that an apparent problem may simply be an indication the machine is working properly."

You sure got that right

Sometimes just simply switching from disc to all metal or vice versa can help alot.

Clives books are great

 

[Tony in FL]

I've got 2 Excal II's Tony. Both have 8" coils. My oldest seldom ever falses even in very rough water. I can run the sensitivity very high and it's still smooth and stable and it goes deep. My newest machine is not like the 1st. It does exactly what you are describing. Even with the sensitivity at a very low setting it falses a lot in wave action. In calmer water and on the beach it does just fine. I have no idea why my older Excal II is so much more stable but the newest machine is now my back up. Also, my cousin had an Excal 1000. The thing drove him nuts in water that had any wave action. After his machine was out of warranty he put an 8" Sunray coil on it. Now it's like a completely different machine. His machine is now just as stable in rough water as my 1st Excal II. Might even be more stable and he gets incredible depth with his. So, that's my experience. I have no explanation for what's going on and the differences between Excals.

It seems a little odd that there can be such a difference in stability due to wave action in salt water between two Excal II's with the same size coil. I wonder how common this is and if it suggests a defect in the coil that Minelab can address.

 

[RichW]

I've been wondering the same thing.

 

[davespen]

Joe, Your machine looks great! Keep me posted regarding wear and tear results...and I'd be interested in how the copper shielding holds up as well. Let me know if you detect any deterioration around the edges of the copper sheeting you've applied. I have an Excal housing I've cleaned up and will set it aside pending your feedback. Dave

 

[OldBeechnut]

Dave, I aqua sealed the copper then applied the vinyl decal...should be ok, will let you know come fall....thanks Joe

 

[Tony in FL]

davespen, do you thing this will help. copper EMI sheilding

Pretty slick looking. So is the purpose to allow you to use your machine closer to power lines, other detectors, and electrical equipment while minimizing interference?

 

[OldBeechnut]

[size=large]
Tony

I stole the idea from the excal II and my sovereign xs2, but once I told my engineer friend Greg (diablo scoops) about it he gave me something like this on how it would work.
Electric fields exist whenever a positive or negative electrical charge is present. Sodium chloride (salt) is an ion. An Ion is simple a molecule with a electrical charge, Water ruptures the bond, giving you Sodium n chloride, giving you both positive n negative charges
Magnetic fields arise from the motion of electric charges. Waves, currents, motion of salt water ...causing EMI/EMF's..therefore the shielding should help. Even shorten my coil cable on his advice, less is better he said.....Will let you know....joe[/size]

 

[davespen]

Great description Joe! In addition, be sure to tightly attach your excess cable as far from the coil as you can (secure upper shaft). Any coil with an electric current will create an electro magnet...the coil cables are not shielded so you don't want that excess coil cable flopping around near your coil as you are detecting....just one more potential source of falsing...

 

[Deep Digger]

Tony,
I understand EXACTLY what you are describing with your Excal.
It happens with mine EVERY time I use it, and I have become accustomed to the falsing
with my excal 2. It even happens when I am in the transition between wet sand and dry sand.
It is constant and omni present.
I used to hate it, now I'm not even phased by it and think something is a miss when I do not hear falsing.
I do NOT think it reduces my good finds. My dad has an excal that runs SMOOTH all the time, even at sensitivity
above 7. I CANNOT run above 6 EVER. The real poop is that I find more than dad on a regular basis and I think it
has to do with my un stable detector. I always have to slow down and re-check falses.. it sometimes pays off with a
deep signal that otherwise would have probably not have been noticed.
If you cannot stand it, sell it.
Mine was made in Ireland and I have used it quite a bit in the past 3 years with flasing every step of the way.
Maybe a new one won't false as much, but your finds might not increase one iota.

Deep Digger