"joe" wrote ...
Szczepan Bia³ek wrote:

So I repeat my question: Are now the FM stations which use the dipoles?

You significant lack of understanding of dipoles is causing you to ask
silly questions that are meaningless.


and Luxembourg has nothing to do with it, your silly frequency
doubling notions should be packaged up in art's box and never see the
light of day.

The dipoles have the directional pattern like this:
http://www-antenna.ee.titech.ac.jp/~...ole/index.html

This shows effects over a 48:1 frequency range. The FM band represents a
1.23:1 range. The image has no bearing on the topic at hand.


It looks like the interference of the many sources (dipoles have the
two).

The two sources not in phase double the frequencies.

This is completely wrong. In a _linear_ systems adding two signals cannot
create new frequencies, including doubling. In the frequency domain this
is clear. If you look in the time domain and look at zero crossings you
may be confused. Do the math for the addition of two sine waves of
different phase.

In reality no sine waves. In the ends of a dipole the voltage is doubled
(VSWR) and the strong picks are radiated.

Stop relying on internet images you don't understand and may not have any
relevance to the discussion.

Discussion is on the harmonics. The dipoles can produce the frequency
doubling.

You can do the math in the time domain, or frequency domain. Either should
tell you there is no doubling of frequencies.

In the school math the water waves are transversal. Look as they are
like: http://en.wikipedia.org/wiki/Stokes_drift

In order to generate new frequencies you need to have a non-linear effect.
Addition is NOT a non-linear operation.

The two picks from the ends of the dipole are not linear.
S*


S*

"Paul Keinanen" wrote
...
On Sat, 20 Mar 2010 09:26:04 +0100, Szczepan Bia?ek
wrote:

It sound like the "Luxemburg Effect". The signal was from the dipole
antenna.

The Luxemburg effect is usually contributed to the suspected Radio
Luxemburg intermodulation products caused by the _ionosphere_
nonlinearities.

Are such products the hours independent? Is ionosphere all time the same.
The dipole on the tip top of the mountain (the both end of the dipole were
:seen") produced the doubled frequency.

Similar intermodulation effects can be obtained by the nonlinearities
caused by rusty bolts in a transmitter tower.

The same was obtained in Warsaw tower (collapsed years ago).
Now Warsaw use monopole.
S*

Joerg wrote:

Michael A. Terrell wrote:
Joerg wrote:
amdx wrote:
"Joerg" wrote in message
...
amdx wrote:
"Richard Clark" wrote in message
...
On Fri, 19 Mar 2010 15:22:42 -0500, "amdx" wrote:

So I installed the antenna on the outside of the boat and the radio
inside,
now one station I listen to is weak, but if I unplug the antenna and
let the
center pin touch ground of the connector on the radio it comes in
great.
Just curious why it is working this way.
Hi Mike,

You moved the antenna.

Most loss of signal as you describe comes from not being a weak
signal, but the mixture of signals that combine negatively at some
spot due to multiple reflections. When you replaced the line cord as
antenna for this better implementation, you also found that "sour (not
sweet) spot." This can occur for any frequency with the equal
likelihood of reflections combining negatively. Move your antenna a
quarter wave and see what happens.

Your description of your having an aluminum boat almost guarantees a
multitude of RF-bright reflections. At short wavelengths, this also
guarantees many, many regions that will exhibit destructive (as well
as constructive) combinations of those reflections.

Put your antenna as far away from the superstructure or hull as
possible. This will reduce the reflection path differences.

BTW, the mod did cure the computer hash.
Mike
FM has what is called a "full quieting" effect. It would suggest that
your first signal levels were just barely above the level of full
quiet (and perhaps not even that good).

73's
Richard Clark, KB7QHC
Richard, after I read your letter I did a little better checking and
found
my signal is not weak it is to strong, I'm getting interference from
other frequencies.
Also I get stations on the wrong frequency.
I went out and collapsed the antenna to minimum about 1/3 of what it
was and
my problem station is perfect and the other station I listen to is still
good. The local
NPR station isn't good though. But I can download the podcast of Science
Friday :-)
Thanks, Mike
The usual, lousy FM tuner. They don't make'em like they used to. It's the
same with television sets, one large signal and they fall off the rocker.

If you have a radio with a signal strength meter you could notch out a
strong station. But that only works it it's just one and far away from the
NPR frequency. The only other options are to get a better radio, a
directional antenna, or just live with it and use the podcast.

--
Regards, Joerg
This morning I got on the boat and the signal that was improved to good by
shortening the antenna is now bad. 94.5 has interference from 101.1.
Oh well!
You really need a better quality radio and with radios and a lot of
other stuff older = better :-)

I mean, considering what the boat must have cost ...


Or a tuned trap to reduce the signal from that one station.


Well, that's what I suggested above, notch = trap :-)

But it's tough and can be impossible if there are useful weaker stations
near the one you want to muffle. In Europe they had a pager service
right at the lower end of the FM band. Whichever committee signed off on
that one should be dunked into a moat for gross incompetence, until they
either learn or quit their career. Anyhow, the inevitable happened, and
despite being a school kid I predicted that: A barrage of complaints by
FM listeners. In Germany they pay a radio tax so that makes them sort of
constituents with rights. Long story short the governement had to
furnish rather expensive notch filters to anyone who complained.


So you move the trap slightly to one side. A good trap can be narrow
enough to only affect one or two channels if it is built with the right
components, but it isn't cheap. Glass piston capacitors and glass
inductors are temperature stable and have a very high 'Q'.


--
Lead free solder is Belgium's version of 'Hold my beer and watch this!'

Szczepan Bia³ek wrote:

"joe" wrote ...

This is completely wrong. In a _linear_ systems adding two signals
cannot create new frequencies, including doubling. In the frequency
domain this is clear. If you look in the time domain and look at zero
crossings you may be confused. Do the math for the addition of two
sine waves of different phase.

In reality no sine waves.

The you had better learn what Fourier analysis is all about.

In the ends of a dipole the voltage is doubled
(VSWR) and the strong picks are radiated.

Stop relying on internet images you don't understand and may not have
any relevance to the discussion.

Discussion is on the harmonics. The dipoles can produce the frequency
doubling.

If that were true radio communications would be much more of a mess than
it currently is. You don't understand antennas and need to start learning.



You can do the math in the time domain, or frequency domain. Either
should tell you there is no doubling of frequencies.

In the school math the water waves are transversal. Look as they are
like: http://en.wikipedia.org/wiki/Stokes_drift

In order to generate new frequencies you need to have a non-linear
effect. Addition is NOT a non-linear operation.

The two picks from the ends of the dipole are not linear.

How would you go about proving that?


S*


S*

joe wrote:
Szczepan Bia³ek wrote:


Joe, he's either a troll or an idiot. It matters little which.
Reasoning with him is fruitless, and he lives in a world where he makes
up his own facts, similar to Art, so facts won't work either.

He's been trolling here off and on for a few months. Most of his posts
run on about the same couple themes.

tom
K0TAR

In article ,
"amdx" wrote:

I have an FM radio inside an aluminum boat. The radio worked ok with the
AC cord as the antenna but I got interference when I used my laptop.
I found the circuit that ran from the power transformer to the antenna input
on the
FM IC. I installed a connector that is used on car radios and wired the
center pin
to the foil that went to the FM IC (capacitor on pcb isolated) and the
shield side to
dc ground near the IC. I then plugged in a telescoping car antenna and it
worked
great on the bench .
So I installed the antenna on the outside of the boat and the radio inside,
now one station I listen to is weak, but if I unplug the antenna and let the
center pin touch ground of the connector on the radio it comes in great.
Just curious why it is working this way.
BTW, the mod did cure the computer hash.
Mike

It's probably a severe impedance mismatch between your new antenna and
the old pickup coil. You might need to create a little step-up
transformer between the board and jack. I looked at a few FM chip specs
and they leave it up to the designer to figure out the right input
transformer. You'll probably need trial and error to figure it out.
--
I won't see Google Groups replies because I must filter them as spam

"Dave" wrote
...
On Mar 21, 12:11 pm, Szczepan Bia³ek wrote:

The dipoles have the directional pattern like
this:http://www-antenna.ee.titech.ac.jp/~...ole/index.html

It looks like the interference of the many sources (dipoles have the
two).

The two sources not in phase double the frequencies.
S*
so why when i switch my transmitter from a 'monopole' where YOU can't

see the other half to a dipole does the frequency stay the same?

Your transmitter has the same but in the receiver antenna is possibility
that appear the doubled frequency.
Luxembourg effect was observed in 1930. Now radio people manage with
eliminating it.
S*

nope, the receiver still hears the proper transmitted frequency.

Yes. THY receiver is tuned to the transmitted frequency.
Luxembourg effect means that another receiver tuned to the doubled your
frequency hears you.
S*

"joe" wrote ...
Szczepan Bia³ek wrote:

"joe" wrote ...

This is completely wrong. In a _linear_ systems adding two signals
cannot create new frequencies, including doubling. In the frequency
domain this is clear. If you look in the time domain and look at zero
crossings you may be confused. Do the math for the addition of two sine
waves of different phase.

In reality no sine waves.

The you had better learn what Fourier analysis is all about.

Real waves are not symetrical. They are like the solitons:
http://paws.kettering.edu/~drussell/.../solitons.html

In the ends of a dipole the voltage is doubled
(VSWR) and the strong picks are radiated.

Stop relying on internet images you don't understand and may not have
any relevance to the discussion.

Discussion is on the harmonics. The dipoles can produce the frequency
doubling.

If that were true radio communications would be much more of a mess than
it currently is.

The mess was in 1930. Remedy was applied.

You don't understand antennas and need to start learning.

I started year ago.


You can do the math in the time domain, or frequency domain. Either
should tell you there is no doubling of frequencies.

In the school math the water waves are transversal. Look as they are
like: http://en.wikipedia.org/wiki/Stokes_drift

In order to generate new frequencies you need to have a non-linear
effect. Addition is NOT a non-linear operation.

The two picks from the ends of the dipole are not linear.

How would you go about proving that?

I am not able to measure the shape of the picks.
You all can.
You can also check the "addition of two" picks (solitons).
S*

Luxembourg effect was observed in 1930. Now radio people manage with
eliminating it.
S*

nope, the receiver still hears the proper transmitted frequency.

Yes. THY receiver is tuned to the transmitted frequency.
Luxembourg effect means that another receiver tuned to the doubled your
frequency hears you.


Perhaps you should read up on what the Luxembourg Effect actually was!!

It had nothing to do with antennas!!

It was Cross Modulation in the ionosphere between Radio Luxenbourg and
other radio stations, where by the modulation of Radio Luxenbourg was
heard superimposed onto the second station.

Jeff

Michael A. Terrell wrote:
Joerg wrote:
Michael A. Terrell wrote:
Joerg wrote:
amdx wrote:
"Joerg" wrote in message
...
amdx wrote:
"Richard Clark" wrote in message
...
On Fri, 19 Mar 2010 15:22:42 -0500, "amdx" wrote:

So I installed the antenna on the outside of the boat and the radio
inside,
now one station I listen to is weak, but if I unplug the antenna and
let the
center pin touch ground of the connector on the radio it comes in
great.
Just curious why it is working this way.
Hi Mike,

You moved the antenna.

Most loss of signal as you describe comes from not being a weak
signal, but the mixture of signals that combine negatively at some
spot due to multiple reflections. When you replaced the line cord as
antenna for this better implementation, you also found that "sour (not
sweet) spot." This can occur for any frequency with the equal
likelihood of reflections combining negatively. Move your antenna a
quarter wave and see what happens.

Your description of your having an aluminum boat almost guarantees a
multitude of RF-bright reflections. At short wavelengths, this also
guarantees many, many regions that will exhibit destructive (as well
as constructive) combinations of those reflections.

Put your antenna as far away from the superstructure or hull as
possible. This will reduce the reflection path differences.

BTW, the mod did cure the computer hash.
Mike
FM has what is called a "full quieting" effect. It would suggest that
your first signal levels were just barely above the level of full
quiet (and perhaps not even that good).

73's
Richard Clark, KB7QHC
Richard, after I read your letter I did a little better checking and
found
my signal is not weak it is to strong, I'm getting interference from
other frequencies.
Also I get stations on the wrong frequency.
I went out and collapsed the antenna to minimum about 1/3 of what it
was and
my problem station is perfect and the other station I listen to is still
good. The local
NPR station isn't good though. But I can download the podcast of Science
Friday :-)
Thanks, Mike
The usual, lousy FM tuner. They don't make'em like they used to. It's the
same with television sets, one large signal and they fall off the rocker.

If you have a radio with a signal strength meter you could notch out a
strong station. But that only works it it's just one and far away from the
NPR frequency. The only other options are to get a better radio, a
directional antenna, or just live with it and use the podcast.

--
Regards, Joerg
This morning I got on the boat and the signal that was improved to good by
shortening the antenna is now bad. 94.5 has interference from 101.1.
Oh well!
You really need a better quality radio and with radios and a lot of
other stuff older = better :-)

I mean, considering what the boat must have cost ...

Or a tuned trap to reduce the signal from that one station.

Well, that's what I suggested above, notch = trap :-)

But it's tough and can be impossible if there are useful weaker stations
near the one you want to muffle. In Europe they had a pager service
right at the lower end of the FM band. Whichever committee signed off on
that one should be dunked into a moat for gross incompetence, until they
either learn or quit their career. Anyhow, the inevitable happened, and
despite being a school kid I predicted that: A barrage of complaints by
FM listeners. In Germany they pay a radio tax so that makes them sort of
constituents with rights. Long story short the governement had to
furnish rather expensive notch filters to anyone who complained.


So you move the trap slightly to one side. A good trap can be narrow
enough to only affect one or two channels if it is built with the right
components, but it isn't cheap. ...
^^^^^^^^^^^^^^^^^^

Bingo!


... Glass piston capacitors and glass
inductors are temperature stable and have a very high 'Q'.


I just hope someone was read the riot act for making that frequency
allocation. I mean, that allocation was really borderline daft ;-)

--
Regards, Joerg

http://www.analogconsultants.com/

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