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What causes a PI to read waves? My quess that it is the sat or the gain of the machine.I thought PI detectors are spost to ignore salt.I just got a seahunter mark II. It reads waves the strange with is I had one 2 years ago and it didn't do this.I can adjust the disc. knob to 1 1/4 and stablize a little better.I did call garrett and Jack said he will look into the circuit to see if there has been any changes since my first one.I just curious to see what the pi experts say.Thank you,Joe
 
Hello joe,
It may be Beach conditions as they can change from one trip to the other, Perfect operating conditions one day may be a nightmare the next.
HH, Paul (Ca)
 
A spray with 'Back to Black' or a similar car product thats just a clear silicon product gives a super slippy finish that won't harm plastic, paint or metal. Protects your machine and reduces noise caused by waves.
 
Hi Brian,
Interesting tip. What detectors have you used this on? If it reduces noise when waves splash on the coil, it would suggest that the coil shielding is not adequate.
With the coil underwater, it is a different story. Say the coil is under two feet of water. Particularly at short sample delays, the water will give a signal due to its conductivity, but the SAT tunes this out. If a wave passes over, temporarily increasing the water depth to three feet, then the amplitude of the signal will go up as the coil is looking at a greater volume. If it is a slow wave, then the SAT can keep up with the increase in signal and compensate for it. For a faster incoming wave, where the SAT can't keep up, then an increase in audio threshold will be noticed. These changes are slow however, compared to the signal change when you pass over a metal target.
PI's are not immune to sea water conductivity, but are much less affected than induction balance detectors. The trend towards shorter sample delays, to pick up smaller and thinner targets will mean some increase in response to waves and swell.
Eric.
 
with the whites pi pro (i could've had a bum one i dont know ) noisy machine evey wave rise in threshold and when you put it in the water and taking it out to me detecting ought to be a serenity kind a thing quiet hell you could be over a nice fat gold ring when you put the coil in the water and you would think it was the sea water thats why i upgraded to the gqss 2 its quiet i must be blessed with a good detector i havent had to move the settings since i got it a couple months ago 10 uS min threshold at about 11:55 almost 12: oclock volume up sat at fast havent touched it the beach must be blessed haha !!! anyway i think what the guy is talking about is the spray silicon it helps the falsing when it is out of the water by making the water run off the coil rather quickly so as not to produce falsing another thing is run the coil wire straight up the post i use electrical tys and then before the s-curve then i wrap it around this should reduce some of the chatter from the waves another thing i used to use on the origianal goldquest was to raise the setting from 10Us to about 25 Us and then turn down the sat to quiet it down or turn down the sat to slow and you could turn up the the reject to 10 Us you kinda had to play with it like paul says the beach conditions change on a daily basis some days were good others not so good hope this helps larry (ca)
 
Hi Joe,
When using the Garrett Sea Hunter Mk 11 and similar units, you may have to turn the discrimination up to about 2 on the scale.
The Sea Hunter at zero discrimination may not eliminate some of the higher salty mineralisation conditions that may be encountered.
Setting discrimination at 2, will not effect the detection capabilities of the unit.
I prefer using the discrete discrimination mode as I get good depth in this mode and also a bit more stable operation to most PI detectors.
I can walk from the dry sand onto the wet sand and into the water without any variations in the threshold or false signalling. This is on our very variable mineralisation beaches in Australia, which also has black sand.
The only place I have ever had problems with the Sea Hunter Mk 11, was on certain beaches on Kaua'i (Hawaai)
Hope this helps out.
Regards,
Phil
 
I guess there is not a whole lot I can do.Also I guess this is a part of the learning curve.Good hunting Joe
 
In bad surf I got up to 3 to settle it down.Don't you lose small gold?I air test it and lost a 1.3 penny wieght white gold ring by 2 disc and by 3 I lost most small med yellow gold.And by 4 to 5 I lost steel cap but still hit on med to large gold.Thank you to all who have given thier insite,good hunting Joe
 
I was told that the threshold should be treated like a sensitive control.I was told if the is to much niose back it down to or just not audio.Is this true.
I feel I will lose those deepper targets.Thanx agian,Joe
 
The only thing we have is salt.This is or can be a problem to some units.Our ground has no or very very little minerals in it so some detectors see the salt and act different then if they were on most beaches.
This is why we get extreme depth with the units that work here in FL.With my Excal I get quarter a easy 17 to 18 inches and sometime 20 if the sand is hard packed.During summer alot of soft or lose sand move in so targets sink fast and deep.This is the reason why I got another pi.I have already hit quarters 20 inches with this mark II and when I learn it better I will hear deepper targets.I am just trying to see why the unit acts like it does so I understand it better or get it tuned up for better stable running.thank you,Joe
 
Dear Joe,
First of all, I'm surprised that you have to go as high as 3 to quieten the unit down due to wave movement. I suggest you run the unit in the discrete discrimination with the discrimination set at 2 where you are having problems with the waves. It should be running fairly quiet at these settings. If it is still getting noises from the waves hitting the coil, then I would get the unit checked, especially the coil as there may be a problem with the shielding.
Now in regards to the air testing of targets with any pulse induction detector, don't, as they use the mineralisation and sand to energise the target. Air is not a good conductor for pulse induction detectors and therefore air testing response of targets will and can be very misleading. In very basic terms, the targets are not getting the proper energising signal, so therefore the signal strength decays quicker, giving the effect of loss of the target. Another thing that will affect the detection of small rings is the pulse rate frequency that the unit is running at. The higher the frequency, the more sensitive it will be to smaller targets, but a loss of depth will occur and the opposite occurs with lower pulse rate units.
The discrete discrim mode has been enhanced for gold rings, so as I said before, use this mode and it should rectify your problem.
Give it a go and let us know the results.
Regards,
Phil
 
Hi Phil,
A couple of points here that I'd like to pick up on. Air is neutral as regards the operation of PI detectors, indeed for any other type of metal detector also. It neither detracts from, or enhances the signal. Ground mineralisation, whether conductive or magnetic, or sometimes a combination of both, does affect the signal. Sometimes it enhances it, but more generally degrades it. In my opinion, an air test is valuable as setting a benchmark on a detector
 
Got a feeling someone suggested it back in the Deepscan days with the old solid gray coil. Ever since I spray any new machine up to the controlbox as it helps shed mud and sand so easily. If you overspray or don't wipe off at once it has the opposite effect.
 
The treshold should be a very light hum for best depth, if you go to silent zone it will lose depth. It is not a sensitivity control as such, yes the silent zone will reduce the noise and lose depth and I guess on that basis it would be. On the White's I believe you have a gain control, that is sensitivity!
On Erics, if you have SAT control that can help with ground conditions. Waves hiting coil should not really do that or it should adjust quickly, if it doesn't something may be wrong with coil
 
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