Szczepan Bialek wrote:

"Rob" napisal w wiadomosci
...
Szczepan Bialek wrote:
Today, transmitters are often very small and still they work OK without
any earth connection.
How large should a "large conductor" be?

Adequate to electron emission.

Transmitters do not emit electrons.

"Negative corona take place at each voltage:

No, it does not.

Corona only occurs with sufficiently high voltages.

The voltages on most antennas is no where high enough to cause corona.

"A corona is a process by which a current, perhaps sustained, develops
between two high-potential electrodes

There you have it: "two high-potential electrodes".

snip

But in my cellphone, the coax feeding the antenna is maybe only 1cm
long, or even shorter. How can you call it a "large conductor"?

"Large enough."

There is no coax in my cellphone, my 2M handheld, or my aviation handheld.

The cases of all of them are plastic and there is no "large conductor" nor
is there any "ground plane".

Yet they all work.

You are a babbling idiot.

snip

""the tip of a needle, or a narrow wire" is a source of the electrons.

For 12 V it should be the nanometers.

For 12V there is no corona as the voltage is too low to initiate a corona
no matter how small a tip you put on the wire.

Take a rest.

Get therapy.