In cell phone the signal ground is through 2 capacitors and one resistor:
Capacitor #1 formed between phone pcb & user’s hand+ear → Resistance of user’s body from hand to foot → Capacitor #2 formed between sole of the foot and the floor.
That’s just BS.
Mobile phones are perfectly happy laying on a plastic table for example.
You don’t need any reference to earth ground.
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You misunderstood me.
I never said that signal ground is necessary or needed.
What I said is that a signal ground is formed when phone is in use by a person.
The problem with that statement is that the signal ground is already present in the phone no matter if someone is holding it.
So you could say for some frequencies there is a path from signal ground to earth ground.
(Impedance might be high and not qualify as grounding anything though)
Why is it in a closet? 
Geffers
Why not? The antenna is in my automation/comms closet that has an 18’ ceiling. It is the highest point in my 1 story villa (condo). No outside antennas are allowed.
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OK, interesting sentence. Bu it still does not explain why.
And how is your Ethernet grounded? The power is not coming from “nothing”. At the beginning there’s always a power source.
Good explanation. Just wondered as many suggest indoor aerials best by a window. Having said that, my antenna by a NW facing window and I pick up plenty of aircraft about 10 miles SE at around 9000 feet on Heathrow approach.
Geoff
The Ethernet is not grounded and the power is provided by a wall wart which is double insulated and by definition (in Australia) must not be connected to earth.
I’m not sure which part. This antenna for instance requires an earth regardless of indoor or outdoor mounting
UTP (typically cat5, cat6) provides four balanced signal pairs which are used for differential signals.
By definition, neither side is grounded.
STP is grounded. My radarcape came with an STP ethernet cable.
The ground, however, is for the shielding, not for power.
Surely if the signal were grounded, the phone wouldn’t work at all.
STP may be grounded.
Most RJ45 sockets do not have a contact for the shield.
As you say, not relevant for PoE.
In practice it is usually only grounded at one end to prevent earth loops and to prevent current flowing due to different earth potential at each end.
S
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Antennas must be grounded, bot electric power not? Strange…
This part sound somewhat funny:
an antenna that needs a ground will need a ground
