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#1
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![]() "Phil Allison" wrote ... "Richard Clark" Now, as to your experience of receiving signals on the wrong frequency, that is a classic situation of image rejection being poor due to the lack of a tuned front-end (something that dissappeared with the dinosaurs). If I were to guess on the basis of 40 year old experience fixing these suckers, your off-frequency signals are probably shifted by twice the IF frequency of your receiver. The classical FM IF frequency of 10.7 MHz might apply, but time has marched on and designers may select their own. This old standard would argue that you shouldn't experience images except where they would be out-of-band (the 88-107 band with this IF would force that). ** Hearing the same FM station at more than one spot is still possible even with a 10.7 MHz IF frequency - if the signal is very strong. The reason is harmonics of the incoming carrier generated in the RF stage interacting with harmonics of the local oscillator in the mixer. It sound like the "Luxemburg Effect". The signal was from the dipole antenna. Are now the FM stations which use the dipoles? Eg: A 100MHz FM carrier generates a harmonic at 200MHz in the receiver. When the local oscillator is adjusted to 94.65 MHz, its second harmonic is 189.3 MHz. The difference frequency is then 10.7 MHz - so goes through to the FM detector. In this situation, the FM deviation is doubled so the recovered audio will be distorted on loud passages. S* |
#2
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The usual solution on boats: Use a decent car radio.. Well shielded,
expects outdoor antenna. Runs on 12Volts... Can be had with CD player, separate input for your Ipod etc.., good audio power to speakers etc.... And designed to work inside a metal vehicle.... |
#3
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TerryKing wrote:
The usual solution on boats: Use a decent car radio.. Well shielded, expects outdoor antenna. Runs on 12Volts... Can be had with CD player, separate input for your Ipod etc.., good audio power to speakers etc.... And designed to work inside a metal vehicle.... Best of all, it can be bolted down. That's really important on a boat. However, many newer car radios (newer as in "last 20-30 years") don't have very good tuners. Best to get one from the era of Ge-transistors, those radios were usually good. Better yet, get an Icom, Yeasu or whatever comms receiver. Most have a WFM setting. Ok, no stereo sound but one can easily listen to NOAA radio, ship-to-shore channels and so on. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |
#4
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On Mar 20, 8:26*am, Szczepan Białek wrote:
*"Phil Allison" ... "Richard Clark" Now, as to your experience of receiving signals on the wrong frequency, that is a classic situation of image rejection being poor due to the lack of a tuned front-end (something that dissappeared with the dinosaurs). *If I were to guess on the basis of 40 year old experience fixing these suckers, your off-frequency signals are probably shifted by twice the IF frequency of your receiver. *The classical FM IF frequency of 10.7 MHz might apply, but time has marched on and designers may select their own. *This old standard would argue that you shouldn't experience images except where they would be out-of-band (the 88-107 band with this IF would force that). ** *Hearing the same FM station at more than one spot is still possible even with a 10.7 MHz IF frequency - *if the signal is very strong. * The reason is harmonics of the incoming carrier generated in the RF stage interacting with harmonics of the local oscillator in the mixer. It sound like the "Luxemburg Effect". The signal was from the dipole antenna. Are now the FM stations which use the dipoles? Eg: A 100MHz FM carrier generates a harmonic at 200MHz in the receiver. When the local oscillator is adjusted to 94.65 MHz, its second harmonic is 189.3 MHz. The difference frequency is then 10.7 MHz *- *so goes through to the FM detector. In this situation, the FM deviation is doubled so the recovered audio will be distorted on loud passages. S* all antennas are dipoles, you just can't always see the other half. 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. |
#5
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![]() "Dave" all antennas are dipoles, you just can't always see the other half. 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. ** ROTFL !! Dave should be writing scripts for Mickey Mouse cartoons. Cos he has the IQ of Daffy Duck. .... Phil |
#6
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On Mar 21, 11:34*am, "Phil Allison" wrote:
"Dave" all antennas are dipoles, you just can't always see the other half. 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. ** ROTFL *!! Dave should be writing scripts for Mickey Mouse cartoons. Cos he has the IQ of Daffy Duck. ... * Phil just trying to put it on S.B.'s level of understanding. |
#7
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![]() "Dave" wrote ... On Mar 20, 8:26 am, Szczepan Białek wrote: "Phil Allison" ... "Richard Clark" Now, as to your experience of receiving signals on the wrong frequency, that is a classic situation of image rejection being poor due to the lack of a tuned front-end (something that dissappeared with the dinosaurs). If I were to guess on the basis of 40 year old experience fixing these suckers, your off-frequency signals are probably shifted by twice the IF frequency of your receiver. The classical FM IF frequency of 10.7 MHz might apply, but time has marched on and designers may select their own. This old standard would argue that you shouldn't experience images except where they would be out-of-band (the 88-107 band with this IF would force that). ** Hearing the same FM station at more than one spot is still possible even with a 10.7 MHz IF frequency - if the signal is very strong. The reason is harmonics of the incoming carrier generated in the RF stage interacting with harmonics of the local oscillator in the mixer. It sound like the "Luxembourg Effect". The signal was from the dipole antenna. Are now the FM stations which use the dipoles? Eg: A 100MHz FM carrier generates a harmonic at 200MHz in the receiver. When the local oscillator is adjusted to 94.65 MHz, its second harmonic is 189.3 MHz. The difference frequency is then 10.7 MHz - so goes through to the FM detector. In this situation, the FM deviation is doubled so the recovered audio will be distorted on loud passages. all antennas are dipoles, you just can't always see the other half. If I can't see the other half it is the monopole. So I repeat my question: Are now the FM stations which use the dipoles? 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 It looks like the interference of the many sources (dipoles have the two). The two sources not in phase double the frequencies. S* |
#8
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On Mar 21, 11:42*am, Szczepan Białek wrote:
"Dave" ... On Mar 20, 8:26 am, Szczepan Bia ek wrote: "Phil Allison" ... "Richard Clark" Now, as to your experience of receiving signals on the wrong frequency, that is a classic situation of image rejection being poor due to the lack of a tuned front-end (something that dissappeared with the dinosaurs). If I were to guess on the basis of 40 year old experience fixing these suckers, your off-frequency signals are probably shifted by twice the IF frequency of your receiver. The classical FM IF frequency of 10.7 MHz might apply, but time has marched on and designers may select their own. This old standard would argue that you shouldn't experience images except where they would be out-of-band (the 88-107 band with this IF would force that).. ** Hearing the same FM station at more than one spot is still possible even with a 10.7 MHz IF frequency - if the signal is very strong. The reason is harmonics of the incoming carrier generated in the RF stage interacting with harmonics of the local oscillator in the mixer. It sound like the "Luxembourg Effect". The signal was from the dipole antenna. Are now the FM stations which use the dipoles? Eg: A 100MHz FM carrier generates a harmonic at 200MHz in the receiver. When the local oscillator is adjusted to 94.65 MHz, its second harmonic is 189.3 MHz. The difference frequency is then 10.7 MHz - so goes through to the FM detector. In this situation, the FM deviation is doubled so the recovered audio will be distorted on loud passages. all antennas are dipoles, you just can't always see the other half. If I can't see the other half it is the monopole. So I repeat my question: Are now the FM stations which use the dipoles? 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 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? |
#9
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![]() "Dave" wrote ... On Mar 21, 11:42 am, Szczepan Białek wrote: "Dave" ... On Mar 20, 8:26 am, Szczepan Bia ek wrote: "Phil Allison" ... "Richard Clark" Now, as to your experience of receiving signals on the wrong frequency, that is a classic situation of image rejection being poor due to the lack of a tuned front-end (something that dissappeared with the dinosaurs). If I were to guess on the basis of 40 year old experience fixing these suckers, your off-frequency signals are probably shifted by twice the IF frequency of your receiver. The classical FM IF frequency of 10.7 MHz might apply, but time has marched on and designers may select their own. This old standard would argue that you shouldn't experience images except where they would be out-of-band (the 88-107 band with this IF would force that). ** Hearing the same FM station at more than one spot is still possible even with a 10.7 MHz IF frequency - if the signal is very strong. The reason is harmonics of the incoming carrier generated in the RF stage interacting with harmonics of the local oscillator in the mixer. It sound like the "Luxembourg Effect". The signal was from the dipole antenna. Are now the FM stations which use the dipoles? Eg: A 100MHz FM carrier generates a harmonic at 200MHz in the receiver. When the local oscillator is adjusted to 94.65 MHz, its second harmonic is 189.3 MHz. The difference frequency is then 10.7 MHz - so goes through to the FM detector. In this situation, the FM deviation is doubled so the recovered audio will be distorted on loud passages. all antennas are dipoles, you just can't always see the other half. If I can't see the other half it is the monopole. So I repeat my question: Are now the FM stations which use the dipoles? 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 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* |
#10
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On Mar 21, 12:11*pm, Szczepan Białek wrote:
*"Dave" ... On Mar 21, 11:42 am, Szczepan Bia ek wrote: "Dave" ... On Mar 20, 8:26 am, Szczepan Bia ek wrote: "Phil Allison" ... "Richard Clark" Now, as to your experience of receiving signals on the wrong frequency, that is a classic situation of image rejection being poor due to the lack of a tuned front-end (something that dissappeared with the dinosaurs). If I were to guess on the basis of 40 year old experience fixing these suckers, your off-frequency signals are probably shifted by twice the IF frequency of your receiver. The classical FM IF frequency of 10.7 MHz might apply, but time has marched on and designers may select their own. This old standard would argue that you shouldn't experience images except where they would be out-of-band (the 88-107 band with this IF would force that). ** Hearing the same FM station at more than one spot is still possible even with a 10.7 MHz IF frequency - if the signal is very strong. The reason is harmonics of the incoming carrier generated in the RF stage interacting with harmonics of the local oscillator in the mixer. It sound like the "Luxembourg Effect". The signal was from the dipole antenna. Are now the FM stations which use the dipoles? Eg: A 100MHz FM carrier generates a harmonic at 200MHz in the receiver.. When the local oscillator is adjusted to 94.65 MHz, its second harmonic is 189.3 MHz. The difference frequency is then 10.7 MHz - so goes through to the FM detector. In this situation, the FM deviation is doubled so the recovered audio will be distorted on loud passages. all antennas are dipoles, you just can't always see the other half. If I can't see the other half it is the monopole. So I repeat my question: Are now the FM stations which use the dipoles? 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/~...le/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. |
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