cell phone update

[crock]

Went out today with Boobie and we did a little experiment, Boobie had his phone on him and when he came within 15-20 feet of me my MXT started chattering, He turned his phone off and it stopped, My cell was on in my truck and when I got close to it the chattering started, turned the phone off in the truck and it stopped, I am not sure of the science inveolved but maybe the 14.7 klh is so close to the same freq as a cell that it will not tolerate it, if anyone has any thoughts on this it would be much appreciated!!!!!

[bigjohn]

i thought cell phone were all digital not not analog. but i guess its the freq. also. i think frs and gmrs 2 ways are on ?? 40 or 150 mhz,s but they will mess with a detector. who knows? i have a mxt comming in next week i'll play around with it. what cell provider are you using?.

[JohnWPA]

Great point and glad you posted this also Gives many of us good advice!!!

I concor with both of you...Especially on the Minelabs that have 28 freqs!

Cell towers and cell phones are constantly communicating with each other even though your not talking on them ....when a phone call is made to a cell phone....the tower will send out a page on the paging channel to find that cell phone and start communication!

In the Cellular world they have what they call a uplink and downlink so that a phone can be located anywhere in the Cellular system by a digital signal converted to analog signal through the air on a carrier frequency which effects machines!

Minelab engineers say that Cell towers will effect machines several miles away due to the transmitting distance from a tower....Cell phones will effect only if near metal detector...

John

[ECACE]

MD's are in the low KHZ range (6-20), but cell phones are in the high MHZ range (824 - 1990 for GSM). I would imagine it has more to do with the harmonics of the phone interfering with the MD. Also, an MD is made to be extremely sensitive to RF signals and would not have anywhere the shielding to prevent false signals (Phone RF in the case) from interfering with it. Whether it is digital or analog doesn't matter, when the signal leavs the phone, it is RF, which is what's messing with your MD.

Somewhere in or on your detector or literature, there may be an FCC note about it being a class 15B device. A quote about part 15B devices, which I would imagine MD's fall under as they are very small transmitters themselves: "the rules stipulate that the devices must not cause harmful interference to other radio services and must accept any interference caused by the legal operation of other radio services."

It's just the nature of the beast and not a lot we can do with it. My CZ-3D starts chattering and flipping out when I'm in my yard and I get close to the window where my Wi-Fi is located, and I know when my neighbor is on her cordless phone, because the same thing happens. I have been outside MD'ing and she was outside on her phone. Once she ended the call, all of my chattering and falsing went away. I have experienced this 2 times!

I know this was rather long and hope I didn't bore you too much, but that's my 2 cents on it.

Eric

[crock]

I am glad I am not the only one!!! I have been going crazy trying to figure out why sometimes the detector is quiet and then goes south on me, especially near houses, this really helps.

[mark4583]

So will the Towers still track your phone even if your turn it off?

[ECACE]

If the phone is powered down, then no, it shouldn't interfere. But if the phone is on and you are not talking on it, it will still ID itself so the network knows it is there. Kinda like waving it's hand in the air every now and then to remind the network that if it needs to transfer a call to the phone, here are the towers that heard from it last and are most likely going to be able to contact the phone.

I can't even have my GSM phone on my dresser, which has the TV in the living room on the other side of the wall. Whenever the phone ID's itself, it messes with the TV.

Eric