napisa³ w wiadomo¶ci
...
Szczepan Bialek wrote:


In AC electrons oscillate. In DC electrons are flowing for ages.
Where they come from?

No; in AC electrons periodically change directions and in DC electrons
flow in one direction only.

An antenna is a device that converts the electromagnetic energy which
antenna intercepts
into AC electrical energy at it's terminals.

A diode converts AC into DC.

The crystal radio antenna has only one terminal. Before the diode is AC.
After the diode is DC.
Where electrons come from?
S*

Szczepan Bialek wrote:

napisa³ w wiadomo¶ci
...
Szczepan Bialek wrote:


In AC electrons oscillate. In DC electrons are flowing for ages.
Where they come from?

No; in AC electrons periodically change directions and in DC electrons
flow in one direction only.

An antenna is a device that converts the electromagnetic energy which
antenna intercepts
into AC electrical energy at it's terminals.

A diode converts AC into DC.

The crystal radio antenna has only one terminal. Before the diode is AC.
After the diode is DC.
Where electrons come from?
S*

There should always be a DC path around the diode, or the crystal radio
will not work.

Normally there is a tuned circuit at the input, which consists of a
coil and capacitor in parallel. The DC flows through the coil.

At the output there either is a high-impedance magnetic headphone,
which conducts DC through its coil, or a crystal headphone with a
resistor in parallel for the DC path.

The electrons circulate around the DC path in the receiver.

"Rob" napisa³ w wiadomo¶ci
...
Szczepan Bialek wrote:

napisa3 w wiadomo?ci
...
Szczepan Bialek wrote:


In AC electrons oscillate. In DC electrons are flowing for ages.
Where they come from?

No; in AC electrons periodically change directions and in DC electrons
flow in one direction only.

An antenna is a device that converts the electromagnetic energy which
antenna intercepts
into AC electrical energy at it's terminals.

A diode converts AC into DC.

The crystal radio antenna has only one terminal. Before the diode is AC.
After the diode is DC.
Where electrons come from?
S*

There should always be a DC path around the diode, or the crystal radio
will not work.

Normally there is a tuned circuit at the input, which consists of a
coil and capacitor in parallel. The DC flows through the coil.

"The wire antennas used with crystal receivers are monopole antennas which
develop their output voltage with respect to ground. They require a return
circuit connected to ground (earth) so that the current from the antenna,
after passing through the receiver, can flow into the ground."

Unnormally you can have only the monopole antenna and the diode and ground.

What current is flowing between the diode and the ground?
Is it dependent on the distance from the transmitter?
S*

Szczepan Bialek wrote:
"The wire antennas used with crystal receivers are monopole antennas which
develop their output voltage with respect to ground. They require a return
circuit connected to ground (earth) so that the current from the antenna,
after passing through the receiver, can flow into the ground."

Unnormally you can have only the monopole antenna and the diode and ground.

What current is flowing between the diode and the ground?
Is it dependent on the distance from the transmitter?
S*

Dear Szczepan,

I have explained to you how it works. That explanation is correct.
Please stop adding incorrect information and asking stupid questions.

I know two stupid Poles. Are there more?

Jeff wrote:


I have explained to you how it works. That explanation is correct.
Please stop adding incorrect information and asking stupid questions.

I know two stupid Poles. Are there more?


Is that the same as a dipole?

A dipole consists of two poles. As some Poles can only count to
one, they will have a different explanation.

"Rob" napisa³ w wiadomo¶ci
...
Jeff wrote:


I have explained to you how it works. That explanation is correct.
Please stop adding incorrect information and asking stupid questions.

I know two stupid Poles. Are there more?


Is that the same as a dipole?

A dipole consists of two poles.

Even if one is in air and the second in the ground?
"The quarter wave monopole antenna is a single element antenna fed at one
end, that behaves as a dipole antenna"
S*

"Szczepan Bialek" wrote in message
...


Even if one is in air and the second in the ground?
"The quarter wave monopole antenna is a single element antenna fed at one
end, that behaves as a dipole antenna"
S*

Good afternoon Szczepan. I see that, after several weeks and lots of
postings, you still do not understand the difference between a monopole and
a dipole. Please also note the phrase "behaves as".
Kindest regards, Ian.

In message , Szczepan
Bialek writes



"The wire antennas used with crystal receivers are monopole antennas

The words "almost always, almost every time, almost invariably and
almost without exception" are missing.

As crystal receivers are normally used at low frequencies (long and
medium wave), the obvious antenna to use is an end-fed long wire
monopole. This, of course, requires a ground.

However, in principle, you could use a (probably large) dipole, provided
you modified/designed the circuit of the receiver so that it would take
a balanced input (which would probably also be low impedance).

I'm pretty sure that some of the early radar receiving systems used
essentially a dipole antenna feeding a crystal receiver.





--
Ian

"Ian Jackson" napisal w wiadomosci
...
In message , Szczepan Bialek
writes



"The wire antennas used with crystal receivers are monopole antennas

The words "almost always, almost every time, almost invariably and almost
without exception" are missing.

As crystal receivers are normally used at low frequencies (long and medium
wave), the obvious antenna to use is an end-fed long wire monopole. This,
of course, requires a ground.

However, in principle, you could use a (probably large) dipole, provided
you modified/designed the circuit of the receiver so that it would take a
balanced input (which would probably also be low impedance).

I'm pretty sure that some of the early radar receiving systems used
essentially a dipole antenna feeding a crystal receiver.

You are right:
"A simple rectenna element consists of a dipole antenna with a diode
connected across the dipole elements." And:
"A nantenna is a very small rectenna the size of a light wave, fabricated
using nanotechnology, which acts as an "antenna" for light,"

Each rectenna arm (or dipole element) must be shorter then 1/4 WL.

But: "Where the electrons come from?
S*

In message , Szczepan
Bialek writes

"Ian Jackson" napisal w wiadomosci
...
In message , Szczepan Bialek
writes



"The wire antennas used with crystal receivers are monopole antennas

The words "almost always, almost every time, almost invariably and almost
without exception" are missing.

As crystal receivers are normally used at low frequencies (long and medium
wave), the obvious antenna to use is an end-fed long wire monopole. This,
of course, requires a ground.

However, in principle, you could use a (probably large) dipole, provided
you modified/designed the circuit of the receiver so that it would take a
balanced input (which would probably also be low impedance).

I'm pretty sure that some of the early radar receiving systems used
essentially a dipole antenna feeding a crystal receiver.

You are right:
"A simple rectenna element consists of a dipole antenna with a diode
connected across the dipole elements." And:
"A nantenna is a very small rectenna the size of a light wave, fabricated
using nanotechnology, which acts as an "antenna" for light,"

Each rectenna arm (or dipole element) must be shorter then 1/4 WL.

But: "Where the electrons come from?
S*

The product of a deranged mind?
--
Ian