It should be kept in mind that a lot of stories where 'hams" are blamed for something are often a result of something an illegal CB operator is doing. The subject doesn't come up in conversation much, but at least 80% of the time when it does, people have no idea what ham radio is or that there is any difference from CB radio. Thus, ham radio operators cause TV interference is a commonly held viewpoint.
Ham Radio knocks out Fire Alarm Radio system
- Thread starter markspoo
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RFI-EMI-GUY
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The original poster would be more likely to get help if he orovides tge callsign and frequency of the ham station being implicated. By the way, it is not unusual to hear amatuer repeater activity in the 460 MHz band due to spurious responses, IF frequency images related to the poor design of the commercial RECEIVER.
Then you should be talking to the ham in question or the technical person in charge of the fire alarm system in Arizona.....not Radio Reference.
mesocyclone
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Not a harmonic unless 6 meters
That frequency is not a harmonic unless the ham was on 6 meters, in which case it's the 9th harmonic. I would be surprised if that's the case.
If it is intermodulation, then the problem could be the fault of the receiver, another radio at the same site as the receiver, a radio at the same site as the transmitter, or other sources of nonlinearity.
If it were a spur (spurious radiation), it could be from a low quality radio (there are some Chinese ham radios that aren't that great in that regard), or it could be from an amplifier. If the latter, one would not expect it to be stable in frequency.
I have done a some hunting for interference as a ham who maintains repeaters in Arizona. The causes are sometimes far from obvious. For example, one source of intermod was a cable rubbing against another cable on a tower., creating a diode which was the source of nonlinearity.
At this point, we cannot know the cause. It would make sense, however, for a public safety critical function like that to not put all of its eggs in one frequency basket, but that would depend on licensing and the technology. Frankly, I wouldn't put anything critical in that band in this day - there are way too many UHF and VHF emitters around.
If someone finds out the real story, I hope they post it here.
That frequency is not a harmonic unless the ham was on 6 meters, in which case it's the 9th harmonic. I would be surprised if that's the case.
If it is intermodulation, then the problem could be the fault of the receiver, another radio at the same site as the receiver, a radio at the same site as the transmitter, or other sources of nonlinearity.
If it were a spur (spurious radiation), it could be from a low quality radio (there are some Chinese ham radios that aren't that great in that regard), or it could be from an amplifier. If the latter, one would not expect it to be stable in frequency.
I have done a some hunting for interference as a ham who maintains repeaters in Arizona. The causes are sometimes far from obvious. For example, one source of intermod was a cable rubbing against another cable on a tower., creating a diode which was the source of nonlinearity.
At this point, we cannot know the cause. It would make sense, however, for a public safety critical function like that to not put all of its eggs in one frequency basket, but that would depend on licensing and the technology. Frankly, I wouldn't put anything critical in that band in this day - there are way too many UHF and VHF emitters around.
If someone finds out the real story, I hope they post it here.
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