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#1
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I have a rfi noise that is throughout the entire shortwave spectrum
(0.1-30 mhz) at about an equal strength - it occurs approximately every 60 khz (and sometimes every 30 khz). The noise is very strong - S9 - S9+20 db, on a very short antenna (6 feet) to my Drake R8, despite my radio being 25 feet or more from the noise source. The noise comes from a nearby appartment. The noise is 24 hours/day and has been going on ever since I moved (over 1 year). It occasionally drops in strength for 1 second. A couple of the noise spurs have a beep noise that is happening once per second (could it be some kind of clock/timer?). It generally sounds like a digital hash (eg more of a hash than a buzz sound). I'm wondering - what kind of device would produce this noise? |
#2
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Aaron Kreider wrote:
I have a rfi noise that is throughout the entire shortwave spectrum (0.1-30 mhz) at about an equal strength - it occurs approximately every 60 khz (and sometimes every 30 khz). Do you also see this on a TV set with external antenna/rabbit ears (NOT cable)? Try low VHF (channels 2-3-4). The noise is very strong - S9 - S9+20 db, on a very short antenna (6 feet) to my Drake R8, despite my radio being 25 feet or more from the noise source. The noise comes from a nearby appartment. How do you know that it's from a 'nearby apartment' and not from outside the building? Do you have a battery operated receiver that you can use to check outside? The noise is 24 hours/day and has been going on ever since I moved (over 1 year). It occasionally drops in strength for 1 second. A couple of the noise spurs have a beep noise that is happening once per second (could it be some kind of clock/timer?). It generally sounds like a digital hash (eg more of a hash than a buzz sound). I'm wondering - what kind of device would produce this noise? Could be *anything*. If you are sure it's originating in the building, try working with the super or the building maintenance manager. Also, see if any of your neighbors are getting any radio or TV interference...that will give you more leverage with the super. Sorry to be so brief, but numerous entire books have been written on interference tracking. Hopefully, this will at least point you in the right direction and allow you to gather a little more information for us. |
#3
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On Jan 17, 10:42 pm, Aaron Kreider wrote:
I have a rfi noise that is throughout the entire shortwave spectrum (0.1-30 mhz) at about an equal strength - it occurs approximately every 60 khz (and sometimes every 30 khz). The noise is very strong - S9 - S9+20 db, on a very short antenna (6 feet) to my Drake R8, despite my radio being 25 feet or more from the noise source. The noise comes from a nearby appartment. The noise is 24 hours/day and has been going on ever since I moved (over 1 year). It occasionally drops in strength for 1 second. A couple of the noise spurs have a beep noise that is happening once per second (could it be some kind of clock/timer?). It generally sounds like a digital hash (eg more of a hash than a buzz sound). I'm wondering - what kind of device would produce this noise? You face a tough task. Finding RFI in a subdivision with separate homes can be daunting, but in an apartment or condo complex is almost impossible. Try to obtain a battery operated receiver such as a DX398. While you can carry a R8 around, it will attract unwanted attention, trust me on this, and it is really hard to carry a R8B, a gel cell and actually use the receiver. A sensitive MW (AM BCB 540~1700) may work. First just do a walk through, floor by floor and hallway by hallway. If you are lucky you will find a 'noise bubble' that is centered on one area. If the noise bubble covers the entire building, then you are in all probability out of luck. If the RFI is being distributed by power lines, phone lines or other conductors the situation is almost hopeless. Even if you manage to find a single RFI source, you will almost certainly not be able do anything about it. Apartment managers really won't care about your RFI complaints. Getting the FCC (assuming you are here in the USA) interested will be almost impossible. I have fought several nasty RFI sources and only in one case could I get the FCC interested. And in that case it really wasn't me it was the FAA because the noise was causing them problems. I found spurs in the aircraft band and when I contacted the local FAA flight service station and found they had the same RFI. Since I had it pretty much pinpointed, down to 2 houses about 4 miles from me and 2 miles from the local airport, the FCC 'swooped in' and shut down a guy who was building a massive parallel processing computer. He had over 50 PII motherboards in bread racks. No RFI shielding at all. They (FCC) gave him the option of shutting it down, or having it all confiscated. He decided to move to Californica where I assume he is noisily working madly away on his monster. The point I am trying to make is that the FCC is seldom interested, and unless the RFI is causing problems for the local police or fire, there is almost no chance of forcing anyone to act on the RFI problem. A friend lived in a downtown condo here in Lexington, KY, finally saw the light of reason and simply moved. He fought RFI for 10 years and in the end accepted that in such a communal living situation, eliminating RFI was a fruitless and hopeless task. Sorry to be so negative but I try to be a realist. You might find it useful to consider doing your DXing from a city, county or state park or wild life refuge. For serious DX I go to a friend's cabin that is located deep in the Daniel Boone National Forrest, far away from all man made noise sources. We had 4 power outages in late December and into New Year's eve. And I had a wonderful time with all of the local, within a mile, AC QRM was simple gone. If it wasn't so cold, another power outage would be fun. Of course it will get down to 4degrees F Saturday night, which might make DXing less then fun. Terry |
#4
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#5
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![]() wrote: If it wasn't so cold, another power outage would be fun. Of course it will get down to 4degrees F Saturday night, which might make DXing less then fun. msg wrote: You're relatively in the tropics; we expect perhaps -20 F on Sat. night with windchills to -60 F. here. Where is "here"? |
#6
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G'day Aaron,
A very similar thing happened to me!! I track the bugger down to Touch Lamps. They are the most if not worse than CRT tv and computer monitors, source of RFI. Touch lamps are "on" in principle 24x7 until you tounch them and the light turn on and off, but to totally off etc. If your nieghbour(s) has them, then hmmmm not sure what you can do dipolmatically and cheaply ![]() For me, told the wife whats what (in otherwords beggged) and got new lamps (The expensive ones she liked). Another couple of suggestions / possible source are 1. Broadband over power lines (BPL) or worse 2. These new home network things that you can network your house through the power sockets using a network to power socket thingy that plugs into the power socket and acts as a network .... Regards Mark ------------------------------------------------------------------ Location: Canberra Australia Radio: Icom R75 with DSP options Antenna: Cliff Dweller 2 Website: http://aussiedrifter.blogspot.com/ Listen Live via USTREAM.TV: http://www.ustream.tv/channel/aussie...wave-listening Aaron Kreider wrote: I have a rfi noise that is throughout the entire shortwave spectrum (0.1-30 mhz) at about an equal strength - it occurs approximately every 60 khz (and sometimes every 30 khz). The noise is very strong - S9 - S9+20 db, on a very short antenna (6 feet) to my Drake R8, despite my radio being 25 feet or more from the noise source. The noise comes from a nearby appartment. The noise is 24 hours/day and has been going on ever since I moved (over 1 year). It occasionally drops in strength for 1 second. A couple of the noise spurs have a beep noise that is happening once per second (could it be some kind of clock/timer?). It generally sounds like a digital hash (eg more of a hash than a buzz sound). I'm wondering - what kind of device would produce this noise? |
#7
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"couple of the noise spurs have a beep noise that is happening once per
second (could it be some kind of clock/timer?)" also digital hash. Had this, it was apparently feeding into my house via the cable system. The cable guy mentioned that it may be some type of local medical appliance causing the problem, radiating to the cable lines, but I've also had this at a different location as well. The cable company itself could be the culprit? Disconnect your cable at the in connection usually outside at the box attached to your wall. Just break the seal and disconnect it....tell them it might have been some kids that did it, if they even ask. If this fails, run the radio from a battery source and shut the main breaker off. This will at least let you know if the interference is from either outside the house or in. "AussieDrifter" wrote in message ... G'day Aaron, A very similar thing happened to me!! I track the bugger down to Touch Lamps. They are the most if not worse than CRT tv and computer monitors, source of RFI. Touch lamps are "on" in principle 24x7 until you tounch them and the light turn on and off, but to totally off etc. If your nieghbour(s) has them, then hmmmm not sure what you can do dipolmatically and cheaply ![]() For me, told the wife whats what (in otherwords beggged) and got new lamps (The expensive ones she liked). Another couple of suggestions / possible source are 1. Broadband over power lines (BPL) or worse 2. These new home network things that you can network your house through the power sockets using a network to power socket thingy that plugs into the power socket and acts as a network .... Regards Mark ------------------------------------------------------------------ Location: Canberra Australia Radio: Icom R75 with DSP options Antenna: Cliff Dweller 2 Website: http://aussiedrifter.blogspot.com/ Listen Live via USTREAM.TV: http://www.ustream.tv/channel/aussie...wave-listening Aaron Kreider wrote: I have a rfi noise that is throughout the entire shortwave spectrum (0.1-30 mhz) at about an equal strength - it occurs approximately every 60 khz (and sometimes every 30 khz). The noise is very strong - S9 - S9+20 db, on a very short antenna (6 feet) to my Drake R8, despite my radio being 25 feet or more from the noise source. The noise comes from a nearby appartment. The noise is 24 hours/day and has been going on ever since I moved (over 1 year). It occasionally drops in strength for 1 second. A couple of the noise spurs have a beep noise that is happening once per second (could it be some kind of clock/timer?). It generally sounds like a digital hash (eg more of a hash than a buzz sound). I'm wondering - what kind of device would produce this noise? |
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