|[AMRadio] The Physical Reality of Sidebands in the AM signal|
jc at pctechref.com
Wed Oct 5 10:44:22 EDT 2016
On the other hand.
You might imagine a 100 watt transmitter and to make this a simple way to
see let us say it is a plate modulated class C rig. When the Rig is not
modulated the receiver receives a signal carrier of say 100uV and the S
meter reads the same regardless of the bandwidth. Now modulate the rig to
say 100% with a 3 khz tone. The receiver still sees the same S meter sig
strength regardless of bandwidth. However if the receiver is set to say a
10 khz bandwidth with a center notch of 1 khz and then center tune to the
carrier and has a notch filter of very deep notch capability so as to
completely get rid of the carrier so the un-modulated sig is now zero on the
S meter. Now when the rig is modulated with the 3 khz tone, the S meter
will read the algebraic addition of the two sidebands less the carrier.
This will be less than the carrier and the S meter should read 50uV which
would be the peak of the algebraic addition of the two sidebands.
I theory a transmitter could be constructed with carrier generator applied
to one antenna and then two other transmitters adjusted above and below the
carrier rig of .25 power of the carrier transmitter and applied to two other
antennas. If the phase relationship is correct then a receiving station
miles away would hear a AM sig. and if constructed just right turning on
the two sideband rigs could make the sig from the carrier frequency
disappear from the receiver.
Sidebands have phasing components that add and subtract from the carrier.
The sideband rigs must be exactly the same freq and phase apart from the
carrier rig as long as there is a difference between the carrier freq rig
and the sideband rigs sine wave modulation would be detected at the distant
receiver. But in order to block the carrier over a long period of time the
two sideband rigs would need to be adjusted to the same freq as the carrier
rig and held at a proper phase as to cancel any signal that the receiver
Here is where the uncertainty thing comes in. It is in the act of receiving
that causes the signal to appear to be canceled. It has been proven that
any electromagnetic waves, radio or light, does not interfere with each
other except in the detection. The interference occurs in the receiving
antenna or apparatus. which BTW is a very good thing else the ether would be
full fo noise caused by all the radio wave interfearing and hetrodyning
creating signals whos bandwidth would never end.
BTW. Two lasers of different freq have been shined on some suface to
produce a third color but only when they or shined on the same spot.
crossing the beams does nothing.
From: AMRadio [mailto:amradio-bounces at mailman.qth.net] On Behalf Of Donald
Sent: Thursday, September 29, 2016 12:50 PM
To: amradio at mailman.qth.net
Subject: [AMRadio] The Physical Reality of Sidebands in the AM signal
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