Threshold adjustment

Ok.... i like most set my threshold at barely audible. But, the Xcal uses pitch hold. Ive used pitch hold on my ML SE out West listening for tiny changes. Those of you who use the Xcal do you set yours when you first turn on the machine.... then again when it sets a louder threshold? I know weak signals have to break the threshold to be heard. Seems going from a loud to weaker threshold would require and adjustment.... at the expense of loosing the threshold most of the time? I believe the loud threshold comes when coming off of iron which makes it more difficult for weak target to break thru.... unlike if it was going from a good target to iron. Is it a non issue and just adjust it when it first comes on?

Dew

Here's a older post from Mike Hillis regarding the F5. Perhaps its applicable.

F5 High Mineralization Deep Coin Hunting Techniques

For deeper coins I recommend these settings:

Run the 2 tone audio. I assume you are using decent headphones. If not, you can forget the deeper coins. The 2 tone audio mode gives the low grunt for iron and the VCO modulated audio for non ferrous targets. You want to pay attention to the non-ferrous targets, especially the ones with short responses and weak audio strength.

Disc no higher than about 8 so you can hear when the iron is falsing.

Gain....The FE bargraph is there to tell you how to set your gain. If you have a maxed out FE bargraph, you can't run a 85 gain. In fact, if you have a maxed out FE bargraph, you really need to be in the all metal mode if you are hunting deep targets. Use that graph. If it is one or two bars, then raise the gain as high as you can. (do not peg it out, turn it only far enough to get the number change. You loose depth if you peg it out) 3 bars....you might or might not get away with higher gain settings. You'll have to figure it out. When you get 4 bars, high gain settings are going to kill your depth, drop it down to the middle range, 55 - 75. Pump your coil for FE readings. ( Don't scrub your coil on the ground with high FE readings either)

The VCO audio needs a positive threshold number to enhance the weaker audio of deeper targets. +5 is good if you can get it that high.
You need to GB spot on. You can't get a spot on GB by ground grab. You have to hear it in the all metal mode and do it manually. Check your ground balance often.

EMI may cause you to have to do a balancing act. If so, I recommend keeping a positive threshold number and a lower gain for the vco audio mode.

The threshold on you excalibur is a disc thresh and not as critical as an all metal thresh....I never fool with it that much unless it becomes distractive or too loud..I set it on a sovereign at startup and leave it alone for the most part....But I would keep it low ....it mainly lets you know that something you have rejected has jus been passed over by resetting to a different tone....But it's not the kind of threshold like you get in the all metal mode that rises and recede's with modulation of target.....

One thing to keep in mind is when the thresh drops out and returns it can be an ultra deep target that is at the edge of disc depth....

I hear people say the excalibur/sovereign is deeper in disc mode.....well it is for I.D. purposes but the all metal side is considerably deeper ...when relic hunting I run the sov in all metal and check with disc...

If you get an all metal hit that is faint and deep check it in disc mode and 9 time's out of 10 it wont even respond,,,,,,Open the ground up to see what it is if the disc side does not even acknowledge it being there...If the disc mode try's to respond but drops the thresh for a second open the ground up....this is where believing that when the thresh drops and returns that it's rejecting trash is wrong..ultra deep target's right on the edge of detection depth will register in the iron range on the sov and act accordingly by dropping the thresh....

The excalibur/sovereign in all metal mode is ultra deep and needs a proper thresh to achieve this but disc is not quite as critical....


I remember when the sov's first came out in the early 90's I had one with the ground tracking set on it and a buddy of mine had one also...we got to experimenting with them in all metal mode using the 11 inch coinsearch coil.....we knew where some deep bullet's were and till this day I have never seen a machine match that depth on the .58 caliber bullet's....we finally resorted to post hole digger's to get them..they were 8-9 inches past the disc depth range.....and yes that had them in the lower 20 inch range.....it was something to behold till this day....but was also an eye opener...

The newer sovs came out and while deep they never could get the depth of the first one's..


I guess this got all off track!?

Keith

Thats sort of what im saying..... the threshold has to be lower for the weak signals to come thru. But with Pitch Hold the threshold once it passes over a target takes on that targets tone.... be it high or low. The low tones seem REALLY loud as opposed to the normal high pitch that comes on when you first turn on and GB the Xcal. Your post supports what im trying to say.... but doesnt answer if i should reduce the threshold based on the highest heard threshold. Got a funny feeling im not making sense lol.

Dew

dew,
are you asking if you should reset the threshold after it increases in volume on its own? i would think that you would be constantly adjusting and i don't think its necessary. mine changes pitch after nulling or hitting a target but i leave it alone or sweep the coil past my scoop until it returns to the original pitch. by the way, my excal is deeper in disc than all metal.
chuck.

It was very interesting to read. How to use this for the F70?

Keith... dont think you got off track at all i know what you are says... thanks. Seeker.... most of the time its been my experience that true AM is deeper than disc. The reason i say that is none of the signals are being processed... the machine only had to say a piece of metal is there, not try to ID it. Ive not used the AM much yet on the Xcal so i dont know what it can do. Once i get the disc mode done then ill move on and increase my experience with some testing. But i know what Keith is saying about those lost thresholds on really deep stuff..... as good as a depth meter any day especially in his type of digs. Seeker yes to what you asked i was talking about doing an adjustment based on the HIGHEST threshold.... but once adjusted to that tone not continually adjust it. Since i havent played with AM...... can you adjust your threshold based on the AM threshold? What brought all this up was i noticed someone who i think is a very good hunter on YouTube and his setting for the threshold was a LOT less than mine. At least i know its not as critical issue. Thanks for some good info guys.

Dew