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Old 02-23-2014, 07:36 AM
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Tom_in_CA Tom_in_CA is offline
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This subject has come up before on threads. I got "shot down" once for saying, as you did, that there IS interference. Either audible (within obvious range), or subtle (below audible, yet still affecting depth). Some answers I got was that I was mistaken, and that cell-phones do not at all operate on the same frequencies, etc.... Not sure of the technical arguments of all that, but here's my experience:

One day I was using a blue-tooth device for my cellphone. The bluetooth was underneath my earphone cup. As I was detecting, I got a phone call. I stopped to answer it. And since the little piece is inside by ear, inside the cup, I thought I could be crafty and continue to detect, WHILE I was talking to my wife on the phone. But I noticed something odd, as the call was going on: All my signals were ratty. As I was talking, I got one particular deeper signal that I wanted to investigate more (thought it might be a deeper turf coin). As I hung up the call, and proceeded to criss-cross over said-signal more, it cleaned up and sounded better.

I am not sure whether it was a) the blue-tooth, or b) the cellphone in-the-middle of a call. When I posed the question, someone made the comment that it wouldn't matter whether there was an actual call in progress OR if the phone was merely in stand-by mode. The reason is: cell-phones are always searching for towers. They are always sending out signals, right? Even if not in an actual call, right? Or does it become different once a call is connected?

And be aware that if there is some sort of cross-talk, it need not necessarily be audible. There is a long-big area of sub-audible, where maybe it's not present-enough to be heard by you, yet can be affecting your depth a little bit. An example of this is when two buddies separate themselves far enough away that their machines no longer cross-talk. HOWEVER, *just* because you're out of the audible range, doesn't mean the problem is totally gone. You need to continue to separate yourselves for a certain distance further, to get out of the in-audible range. I have seen this happen, where a buddy and I had separated ourselves out of audible range. And as I got an iffy signal (possible deep turf silver) that I flagged for him to check, I noticed something interesting. When I made hand -motions for him to come over to my end of the park, he instinctively turned off his machine when he began to walk over. And I noticed that the instant he turned off his machine, my flagged signal sounded clearer and more concise. This was EVEN THOUGH we had been out of audible cross-talk range prior to that. So this leads me to believe that there is a continuing in-audible interference range. Thus the same may be at play with our cell-phones ?
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