|
Hmmm! Interesting one. I have always
assumed that the first point at which the signal(s) caused the
electromagnetic field(s) to develop into voltages/currents and
might then be subject to further processing occurred at the
connection to the antenna or feeder. From that assumption would
follow the surmise that Luxembourg/Gorky or other effects would
result from the phase etc. relationships at that point and then
perhaps be followed by 'distortions' etc. in non-linear stages.
This thought follows from the concept that there is 'nothing'
going on until the radiated field(s) of RF energy excite current
flow in the antenna thus giving rise to voltages at the receiver
input. Maybe this is simplistic but it is how I have understood it
for more than 55 years.
73
On 11/09/13 10:55, Alan Melia wrote:
Hi Edgar.......Or if the receiver
is operating in a linear mode.....then straight addition, but
probably only with SSB detection, an AM demodulater diode is
non-linear :-))
If you add the signals coming
from the same transmitter but over slightly different paths
which alters the phase at the receiver, you get fading but
this is only obvious is one or both path lengths changes.
Alan
G3NYK
----- Original Message -----
Sent: Wednesday, September
11, 2013 10:10 AM
Subject: Re: LF: Radio
signals
Hi
Non linearity in the first RX stage? Caused by a
fault in the stage or over driving of the stage.Or some
very bad corrosion in the joints of the antenna leads. etc
etc. Check your RX, try fitting an attenuator in the
antenna lead or shorten your antenna.
73 es GL Pete M0FMT IO91UX
Hi Group,
What is the mechanism for the way radio signals combine
in the air?
For example
1.There are two transmitters each sending out the same
fixed frequency
sine wave signal.
2. There are no other signals in space, and no
background noise.
3. There are no propagation factors modifying the
signals.
e.g. buildings, ionosphere layers.
4. Both transmitters are the same distance from the
receiver.
5. Both signals have the same polarisation.
How have the signals combined when they reach a
receiving antenna at a
reasonable distance from both transmitters?
It the process addition, multiplication or some other
process?
Regards, Edgar
Moonah, Tasmania.
--
73 de pat g4gvw
es gd dx
qth nr Felixstowe
East Coast UK
|
|
