Adding another counter to perfmon.msc: Add Counter -> Processor -> Interrupts/sec Furiously moving the mouse around the screen, I can't see any interrupts on the graph. It would seem that the USB mouse does not use interrupts. Instead, HID devices are polled: "... standard USB mice are often polled at a default rate of 125 hertz..."
I've heard the same thing, especially on laptops, with have audio isolation problems. In this case, I suspect that's what the OP was hearing, but riding on some kind of RF 600 KHz RF carrier or RF noise source.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
If the station on 600 KHz is in the USA, they might also provide live streaming audio via the internet. Yeah, I know it's cheating, so save this as the last resort.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
My parents, relative and ancestors were all Polish. Believe me, I know all about poles.
(I know it's a stretch but it's the best I could conjure on such short notice).
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
I use a loop antenna that measures 16 inches square. Easy to interface, just orientate the thing, set the radio a few inches away, and tune the cap. No wire connections and I get all kinds of DX. I get almost 1 volt p-p directly from the antenna from a strong local station, but it doesn't help the noise problem, just makes it worse.
The radio is about 8 feet away but it doesn't make much difference. I have another radio in my bedroom that has the same problem. I can hear this noise at 60 feet outside my front door. It's almost bad enough to make the neighbors complain. I tried a large ferrite core on the power cord with 8 turns. The ferrite is the low Q type for filters but doesn't help much. I thought it did since when I first tried it, the noise was gone for 5 minutes or so. But then the frequency slowly creeps up and starts to become noticeable and then settles right on the station frequency and wipes it out.
Well, start with the ferrite-clamp filters - on EVERY wire, not just the power cord. If you're lucky, you'll find the unintended antenna that way. Don't forget lamp cords, or wallwarts for chargers, either! Then, consider your house wiring; if it includes knob-and-tube wiring, there can be large induced loop currents. Try plugging into a different outlet (nearer the fuse panel) using an extension cord.
Buy a new computer case, or power supply, if those might be culprits (it sounds drastic, but it's relatively inexpensive).
As a last resort, see if you can get Internet audio streaming from the favorite station.
I'd start by unplugging the modem cable first - it's the longest antenna.
There was at least one batch of power supplies in Britain, where the Chinese manufacturing engineer economized by leaving out all power line filter capacitors and replacing filter chokes with jumper wires. The case was caught when one of the power supplies ended to the GPO laboratory inside a new computer. The units had the CE stamps, which implies accepted EMC/EMI testing, but it seems that the stamp was interpreted in this case as 'China Export'.
1)One system that works, if you have an antenna input jack on your receiver, are noise cancellers. This is a box that has two antenna inputs. Inside the box is an (optional) amplifier, an adjustable phase shift network, and an amplitude adjustment that feeds a network (hybrid?) that allows the two signals to add, vectorwise.
The input from one antenna (the sense antenna) is matched in amplitude and set opposite, in phase, from the signal on the main antenna. So if the sense antenna is set up to mostly pick up the local noise, it gets reduced.
There are/were a couple of companies that made these commercially (MFJ and at least one other), and there are a number of projects on the web.
I use a passive (no amp) design out of an old (circa 1970) book from the ARRL on RFI and Noise that I got off a web site. It's good for reducing the local noise I get from my neighborhood's lighting systems (mostly the switching supplys feeding halogen room lighting) by about 40 dB on the 6 Mhz shortwave band.
2) A quick thing to try is counterpoise. Hook a hunk of wire to the chassis ground of your radio. This is a local antenna that picks up the noise and if you find the right magic position it can cancel some of it out. Another way is to hook the chassis ground of the radio to one circuit or the other of wall socket through a low value (but high voltage) capacitor.
Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.