View Single Post
  #261   Report Post  
Old July 25th 12, 05:24 PM posted to rec.radio.amateur.antenna
Ian Jackson[_2_] Ian Jackson[_2_] is offline
external usenet poster
 
First recorded activity by RadioBanter: Nov 2007
Posts: 568
Default UK earthling - was: Dipole-2 different wire sizes?

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