All,
I have an RFI problem that I'm trying to identify. It's a continuous pulse noise that pops on every 1/2 second. The timing between each pulse is perfect (about 0.533 seconds) and doesn't seem to change.
The noise is spread accross all HF bands and on some days it seems to creep up into the 100MHz range; it's also stronger on the lower frequencies. The signal is directional and goes from almost nothing to S-8 with the antennas pointed south.
The noise appeard suddenly in December and has not stopped. I have a recording and would appreciate any suggestions.
Thanks,
Tony -K2MO
On Jan 20, 2008, at 5:59 PM, Tony wrote:
I have an RFI problem that I'm trying to identify. It's a continuous pulse noise that pops on every 1/2 second. The timing between each pulse is perfect (about 0.533 seconds) and doesn't seem to change.
The noise is spread accross all HF bands and on some days it seems to creep up into the 100MHz range; it's also stronger on the lower frequencies. The signal is directional and goes from almost nothing to S-8 with the antennas pointed south.
The noise appeard suddenly in December and has not stopped. I have a recording and would appreciate any suggestions.
One initial thought.
First... make sure it's not in your own "backyard". Run the receiver affected off of battery power and kill the main to your house. (Don't forget to turn off anything on a UPS.)
If it disappears, you know where to start hunting, at least, and it's an easy test.
Consumer electronic gear is getting consistently noisier (is this stuff passing any RF testing at all?) and often-times your own "toys" are making the RF racket.
-- Nate Duehr, WY0X nate@natetech.com
Excellent advise! Scanners are notorious for making sounds like this also but more on a single frequency.
Computers are also extremely noisy! When operating HF I never use a computer, every one I have ever had or used, adds at least 10 DB to the noise floor. horrible machines,
Nate Duehr wrote:
One initial thought.
First... make sure it's not in your own "backyard". Run the receiver affected off of battery power and kill the main to your house. (Don't forget to turn off anything on a UPS.)
If it disappears, you know where to start hunting, at least, and it's an easy test.
Consumer electronic gear is getting consistently noisier (is this stuff passing any RF testing at all?) and often-times your own "toys" are making the RF racket.
-- Nate Duehr, WY0X nate@natetech.com
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
If you're sure it's not principally your computer that's causing the problem, you might be interested in the bandsweep tool that's part of recent builds of HamRadioDeluxe. This was mentioned in a recent article in the Amsat Journal (I'm sorry, I forget the author), and I tried it out a couple of nights ago. For me, the visual information provided by that made it much easier to rotate my 2m beam and get a heading on some RFI that I've been struggling with for a long time. With it, you can also identify the birdies that might be signatures of different sources of RFI.
73, Bruce VE9QRP
On Jan 23, 2008 12:13 PM, Joe nss@mwt.net wrote:
Excellent advise! Scanners are notorious for making sounds like this also but more on a single frequency.
Computers are also extremely noisy! When operating HF I never use a computer, every one I have ever had or used, adds at least 10 DB to the noise floor. horrible machines,
Nate Duehr wrote:
One initial thought.
First... make sure it's not in your own "backyard". Run the receiver affected off of battery power and kill the main to your house. (Don't forget to turn off anything on a UPS.)
If it disappears, you know where to start hunting, at least, and it's an easy test.
Consumer electronic gear is getting consistently noisier (is this stuff passing any RF testing at all?) and often-times your own "toys" are making the RF racket.
-- Nate Duehr, WY0X nate@natetech.com
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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On 23 Jan 2008, at 16:13, Joe wrote:
Computers are also extremely noisy! When operating HF I never use a computer, every one I have ever had or used, adds at least 10 DB to the noise floor. horrible machines,
unless you live in the middle of a desert or forest, then switching off your computer probably wouldn't make a blind bit of difference as in a typical street there may be another 100 or so still switched on.
John
On Jan 23, 2008, at 10:12 AM, John Heaton wrote:
unless you live in the middle of a desert or forest, then switching off your computer probably wouldn't make a blind bit of difference as in a typical street there may be another 100 or so still switched on.
Well, the distance-squared rule still applies. Since we can assume that most PC's put out similar levels of RF hash (not always true, but "true enough" for this point), the further away your station is from them, the weaker they will be in your receiver.
The ones under your own roof and the very closest neighbors are really all one typically needs to be concerned with, unless you have a receiver so ultra-sensitive and a high gain antenna pointed at the offending signal source (which someone else already mentioned they were able to do, on purpose, to find their localized noise source).
The real problem is later on, when you have to diplomatically approach a neighbor with your "findings" and ask them if you can assist with cleaning up the offending electronics. That can be more difficult than finding the source, which is often quite a challenge in and of itself.
-- Nate Duehr, WY0X nate@natetech.com
participants (5)
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Bruce Robertson -
Joe -
John Heaton -
Nate Duehr -
Tony