AM Antenna in Eton E1
In article ,
"Lenny" wrote:
So, how exactly do you use the nulls?
Does the ferrite rod move around inside the radio with a control?
Lenny
"Telamon" wrote in message
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In article ,
"Lenny" wrote:
Thanks Telamon.
Lenny
"Telamon" wrote in message
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..
In article ,
"Lenny" wrote:
OK, I'll admit it. I don't know what people are talking about when
they say the E1 doesn't have an AM antenna.
People have stated that the E1 does not have an internal "ferrite rod"
antenna inside.
Doesn't it have a whip antenna.
Yes.
What more could you want?
An internal "ferrite rod" antenna inside.
What the heck is a "ferrite rod antenna" anyway?
It's a closed loop type antenna utilizing a high permeance core (the
ferrite) in order to take up less space.
And what does it do differently than the whip?
1. More convenient to use as you don't have to have the long whip
sticking out when you carry it around.
2. The whip is omnidirectional and the loop ferrite rod antenna has two
nulls in the pattern that you could use to null out a competing station
of local noise source, which could improve your reception.
3. The ferrite loop is less susceptible to pick up local noise sources
being sensitive to the magnetic field component whereas the whip is
sensitive to the electric field.
No problem Lenny.
#2 Should have been "competing station or local noise source."
I need a Usenet editor.
Using the photos provided in the thread by weatherall you can see that
the coiled ferrite rod goes across the top of the case. The nulls are
symmetrical about the rod and exist at the ends of the rod. The "Null"
is where the rod antenna will be the least sensitive to a broadcast
station. The null off both rod ends is a very small just a few degrees
around the rod antenna ends and the maximum reception would be when the
rod antenna is broadside to the station. Due to the length and width of
the rod antenna this almost always means that the radio front or back
should be facing the station.
http://www.radiointel.com/review-tecsunpl200.htm
How to use this to your benefit? Lets say that either another station
or a local noise source is interfering with your reception. You would
point the side of the radio toward the interference reducing the level
of interference. This will only work if the interference is on a
different heading then the station you are trying to hear.
The best use of the null will involve acknowledging that we live in an
(at least) 3D world so whereas the null will be found is by rotating
the radio on a compass heading it can be made "deeper" by aditionally
tilting the radio in the vertical axis.
Here is an analogy as to what you are trying to accomplish by nulling
an interference source. Radio waves are a different frequency of
electromagnetic waves same as light waves. It you had a white rod on a
black background some distance from you holding a flash light next to
your head then the rod would hardest to see when the end of it was
pointed at you representing a small dot. If your eyes were the
interference then the rod would have the least exposure to you when the
end was pointed right at you rotating the rod in the X (compass) and
vertical altitude directions so you can only see the very end of it.
--
Telamon
Ventura, California
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