question about cell phones - Page 2

On 25/11/2017 16:11, John Larkin wrote:


That may well change once you have a phone capable of taking images and  
video clips. The Moto G4 with gorilla glass isn't bad either in terms of  
runtime but nothing can beat the frugal old Nokias 63xx series which ran  
for weeks if all you want is a basic phone.

My Nokia might be one - i found it in a box of junk by recycling bins and  
never bothered looking what model number.

Same service provider as my old Motorola fold and never been configured,  
when the Mot packed up I just relocated the SIM.  

John Larkin wrote:


Just place you cell phone next to powered speakers of your computer, or  
other gear with an amplifier and speaker.  Every few minutes you will hear a  
burst of noise, that is the packets the phone is sending out.

Yes, when far from the cell site, or in the presence of interference, the  
phone has to use more power to keep in touch.

Jon

When I leave my phone near the PC; the pulses of activity come through the  
PC speakers.

There have been detector projects in various magazines involving little more  
than a resonant antenna and a LED.

You only need a fast diode and a small capacitor to detect the RF. An op-amp  
is quite happy with the resulting DC level.  

On Fri, 24 Nov 2017 18:59:43 -0000, "Ian Field"



A fast (3 or 12 GHz) scope probe near the phone should work.

On Fri, 24 Nov 2017 18:59:43 -0000, "Ian Field"



You don't even need the diode or capacitor.  A "decent" bipolar op-amp
will do it all by itself (DAMHIKT).

On Thu, 23 Nov 2017 09:24:22 -0800, John Larkin



Why don't you post this junk somewhere else?

Why don't you do electronics any more?
        
                                        ...Jim Thompson

Pot - kettle......................................