View Full Version : Tracking down an HF noise source
I tried to have a 10m QSO with Jim, KJ3N, this morning and was foiled by a nasty S-3 buzz across the entire band that pretty much wipes out all but the strongest signals. Further investigation showed that it exists over the entire HF spectrum, from 80m on up. I'm not exactly sure how to track something like this down. The 746PRO is a little awkward for portable use.
Any suggestions?
On Edit: It's not emanating from anything in my shack. I turned off everything but the rig. To eliminate a possible problem with the Icom power supply, I also listened with the 736, which has it's own PS built in and heard the noise with it as well.
On Further Edit: I got out my old Sangean ATS-803A portable SWL radio and could clearly hear the noise outside the house. Throwing the main breaker at the service entry point made no difference, so it's not coming from here.
K0RGR
08-26-2014, 01:50 PM
The standard method is to have someone turn off the circuit breakers in your house one at a time until the noise goes away, then track the problem down on the circuit that makes it come and go. A portable AM radio should work for hearing the noise, a portable aircraft band receiver would be better.
The standard method is to have someone turn off the circuit breakers in your house one at a time until the noise goes away, then track the problem down on the circuit that makes it come and go. A portable AM radio should work for hearing the noise, a portable aircraft band receiver would be better.
Done. The noise is not coming from within the house. I walked the neighborhood with a portable HF receiver and the noise seems strongest in the general vicinity of my QTH, but I need a more directional antenna to narrow it down. Unfortunately, it seems as if the noise source is pretty quiet in the AMBCB.
K7SGJ
08-26-2014, 02:09 PM
Carl, you should be able to use the portable radio to help out. See if it is present on the AMBCB. This is the best thing to use, since the antenna inside is a ferrite loop type, and is very directional. The HF antenna is probably a rod and not very directional.
Carl, you should be able to use the portable radio to help out. See if it is present on the AMBCB. This is the best thing to use, since the antenna inside is a ferrite loop type, and is very directional. The HF antenna is probably a rod and not very directional.
We posted within seconds of each other, but see above. There seems to be a peak in signal strength at about 19.5MHz. My radio does have an external antenna jack, so I should be able to rig up some sort of loop antenna.
K7SGJ
08-26-2014, 02:13 PM
We posted within seconds of each other, but see above. There seems to be a peak in signal strength at about 19.5MHz. My radio does have an external antenna jack, so I should be able to rig up some sort of loop antenna.
Good show. Do you get it off station on the AMBCB?
n2ize
08-26-2014, 02:19 PM
If the portable has a gain control bring the gain way down till the noise is way down and move around The noise should start coming up as you get close to the source.
Good show. Do you get it off station on the AMBCB?
No, not hearing it there at all. I'm guessing it's a commercial device that was tested for RFI on the AMBCB but not elsewhere.
If the portable has a gain control bring the gain way down till the noise is way down and move around The noise should start coming up as you get close to the source.
Yeah, it does, and I'm working on that.
XE1/N5AL
08-27-2014, 12:36 PM
One by one, cut the power lines to each of your neighbor's homes until the noise goes away. You can salvage all that wire you've collected for building future amateur radio antenna projects.
Is the noise a constant-pitched buzz, or does it change over time? Is the noise present 24/7, or just during certain hours?
n2ize
08-27-2014, 01:44 PM
Yeah, it does, and I'm working on that.
I had trouble like that back in the 1980's with a strong loud intermittent buzzing when I was on 75 meter Am Phone. It was most noticeable on 75 and particularly when the receiver was wide open on AM. it would come and go, on for a few minutes, off for a minute, on for two minutes off for 5 minutes, but on wet rainy days it was absent. Eventually tracked it down to a leaky insulator on a power pole about 2 blocks away.
One by one, cut the power lines to each of your neighbor's homes until the noise goes away. You can salvage all that wire you've collected for building future amateur radio antenna projects.
What an excellent suggestion! I'll get right on it.
Is the noise a constant-pitched buzz, or does it change over time? Is the noise present 24/7, or just during certain hours?
It's a constant buzz, but there's a background element that's a repeating rise in frequency. As far as timing goes, I need to investigate further. I've heard it in the afternoon, but I haven't listened late at night so I'm not sure if it's there 24/7.
Yesterday, I took a walk around the neighborhood with my portable radio. The nose appeared to be coming from an old farmhouse that's diagonally across the street from my QTH. The guy who lives there was in his yard so I asked him if he'd gotten any new electronic equipment or lighting fixtures lately. He said he didn't, so I'm back to square one.
A fellow member of my ARC is a retired FCC engineer and tonight is the club UHF net. I intend to ask him about my situation. He's still got close ties to the local office (they once brought their "special" van to a meeting, which was pretty cool. I have a picture, but they politely asked me not to post it on the net) so perhaps I can get some help that way.
KC2UGV
08-28-2014, 05:57 AM
We posted within seconds of each other, but see above. There seems to be a peak in signal strength at about 19.5MHz. My radio does have an external antenna jack, so I should be able to rig up some sort of loop antenna.
19.5MHz? Do you have remote meter reading for your gas/water line?
Does the farm house in question have an electric fence charger?
And a charging station for some models of wireless devices (headsets come to mind) puts out garbage on 19.5MHz. I fought the same thing at my place for a couple of years. It went away when the neighbors left. It went away for good when they left for good.
19.5MHz? Do you have remote meter reading for your gas/water line?
All the electric meters around here are remote-reading, but they've been in place for several years now without causing me any problems. They work in the high UHF band. No remote reading gas or water meters that I know of.
Does the farm house in question have an electric fence charger?
Not as far as I know, although they have a huge lot so it's possible that there's something way in back where I can't see it.
And a charging station for some models of wireless devices (headsets come to mind) puts out garbage on 19.5MHz. I fought the same thing at my place for a couple of years. It went away when the neighbors left. It went away for good when they left for good.
This would not surprise me. I suspected that the culprit is some sort of electronic device—a cheap Chinese wall-wart or switching power supply of some sort—right from the get-go.
K7SGJ
08-28-2014, 04:18 PM
Not as far as I know, although they have a huge lot so it's possible that there's something way in back where I can't see it.
This would not surprise me. I suspected that the culprit is some sort of electronic device—a cheap Chinese wall-wart or switching power supply of some sort—right from the get-go.
It might be a noisy vibrator from one of the hookers down the street.
It might be a noisy vibrator from one of the hookers down the street.
If so, she's one hell of a busy hooker.
K7SGJ
08-28-2014, 05:26 PM
If so, she's one hell of a busy hooker.
Aren't they all?
Actually, I heard she used to be a nun. Probably making up for lost time.
kk4fpx
08-31-2014, 01:40 PM
I've had two similar problems in the past one was a floursent lite in another room and the other a 36 volt charger out at the shed.
Funny thing—the noise persisted for several days, then...just disappeared. Go figure.
I'm guessing it will be back again, though.
n2ize
08-31-2014, 02:05 PM
Funny thing—the noise persisted for several days, then...just disappeared. Go figure.
I'm guessing it will be back again, though.
Have any of your neighbors gone away for the weekend ? It's probably some kind of electronic appliance in a nearby home.
XE1/N5AL
08-31-2014, 02:34 PM
Funny thing—the noise persisted for several days, then...just disappeared. Go figure.
I'm guessing it will be back again, though.
Police rounded up all the hookers?
K7SGJ
08-31-2014, 02:41 PM
Funny thing—the noise persisted for several days, then...just disappeared. Go figure.
I'm guessing it will be back again, though.
If it comes back, try smacking the radio with your rubber penis.
Police rounded up all the hookers?
Maybe they get a three-day weekend off for Labor Day?
If it comes back, try smacking the radio with your rubber penis.
The problem isn't with my radio. Better I find the neighbor who's equipment is causing the problem and smack him/her with a rubber penis.
K7SGJ
08-31-2014, 02:54 PM
Maybe they get a three-day weekend off for Labor Day?
The problem isn't with my radio. Better I find the neighbor who's equipment is causing the problem and smack him/her with a rubber penis.
It really doesn't matter what or who you smack, just as long as you get to smack the thing around a little. It's my first choice, even before the Fluke.
It really doesn't matter what or who you smack, just as long as you get to smack the thing around a little. It's my first choice, even before the Fluke.
What happens if you smack a Bushtit with a rubber penis? Is there like a matter-antimatter explosion?
WØTKX
09-01-2014, 09:43 AM
Probably best left unsaid... Just like these NSFW "cliffhangers".
Unfinished (http://forums.somethingawful.com/showthread.php?threadid=3658184&pagenumber=1&perpage=40#post433617758)
K7SGJ
09-01-2014, 02:17 PM
What happens if you smack a Bushtit with a rubber penis? Is there like a matter-antimatter explosion?
After having given this conundrum a considerable amount of thought, I have come to the following conclusion. You would either end up with a rubber penis feather duster, or a little bird with a huge rubber pecker. Of course, I could be full of shit, too.
Of course, I could be full of shit, too.
"Could be".....?
K7SGJ
09-01-2014, 02:32 PM
"Could be".....?
You, too, huh?
Annnnnnnnnnnnd...the noise is back. Just checked, now I'm looking at the ARRL Antenna book for ideas on RDF antennas.
K7SGJ
09-01-2014, 06:29 PM
Annnnnnnnnnnnd...the noise is back. Just checked, now I'm looking at the ARRL Antenna book for ideas on RDF antennas.
Sounds like someone is back from a long weekend.
Time to run down the street smacking everything and everyone with your rubber penis.
I'd check the nunnery first....could be a chickenbander on Da Bowl
KG4CGC
09-02-2014, 08:06 AM
Sounds like someone is back from a long weekend.
Time to run down the street smacking everything and everyone with your rubber penis.
Phone charger.
(oh and bushtit penis pecker)
KG4CGC
09-02-2014, 07:25 PM
I mean, what would one take with them on a long weekend? Phone charger or any other small electronics device charger with a wallwart. Could even be a cheap laptop charger replacement purchased off of ebay.
K7SGJ
09-02-2014, 07:27 PM
I mean, what would one take with them on a long weekend? Phone charger or any other small electronics device charger with a wallwart. Could even be a cheap laptop charger replacement purchased off of ebay.
Rechargeable dildo, maybe? I'm telling youse guys, it's the hooker nuns down the street from him.
KG4CGC
09-02-2014, 07:30 PM
Rechargeable dildo, maybe? I'm telling youse guys, it's the hooker nuns down the street from him.
https://www.youtube.com/watch?v=4kbdzwh_EG4
K7SGJ
09-02-2014, 07:36 PM
https://www.youtube.com/watch?v=4kbdzwh_EG4
You can do that with them, too? Who Gnu?
WØTKX
09-02-2014, 08:11 PM
An HT set to AM in the "VHF air band" is pretty good at finding a lot of this. Or, if you know the SW frequency, just run it on AM mode... many HT's run the SW band thru the ferrite AM BCB antenna, which may or may not help. Look for the noise around 120Mhz +/-?
If you think you are close, pull the HT close to your chest, "behind you" will be blocked.
Spin like a Deadhead listening to "Box of Rain".
I think Da Pope has cursed me. Maybe I didn't give proper penance for something?
A few days ago, I started noticing that familiar buzz. No, I'm not talking about an MJ buzz, unfortunately. Whatever it is, it's doing a good job on clobbering 17m, 15m, 12m, and 10m. For whatever reason, it's not bothering 20m very much and any band lower than that.
Time, once again, to put the IC-7000 in the car to use tracking down yet another aging part of the electrical system around here. I eventually find this about 750-1000 feet away, tucked back in a development built some time in the late 70s.
13036
It might be hard to see, but the transformer looks like it's original equipment. I'm guessing the insulators are as well. I'm sure the tree growing around it, isn't helping, either.
Power company called; pole number given. We'll see how long it takes to get a response.
kb2vxa
09-11-2014, 05:37 PM
I recognize all the standard equipment, but what is that cylindrical object that appears to be floating in mid air at the top of the picture?
K7SGJ
09-11-2014, 05:43 PM
Aliens with a buzz generator.
I recognize all the standard equipment, but what is that cylindrical object that appears to be floating in mid air at the top of the picture?
Looks like an insulator on a guy wire to me.
KC2SYK
09-12-2014, 01:16 AM
Why is everyone having RFI problems this week? I tracked down a RFI issue to a wall wart on my new TP-Link WDR3600 router. Check out what it did to 20m. I disconneced the device at about 21:17:30.
Now I need to figure out whether to try ferrites or just replace the power adapter entirely.
13040
I'll guess a replacement is in order. How that thing ever got Part 15 certification is beyond me.
PA5COR
09-12-2014, 10:35 AM
Tree powerpole 1 gallon fuel wooooofff, problem solved.
Tree powerpole 1 gallon fuel wooooofff, problem solved.
I don't think the people living in the house 60 feet away would appreciate that.
kb2vxa
09-12-2014, 04:03 PM
They would only be inconvenienced for a few hours while the power company replaces the pole and everything on it, no biggie unless Auntie Grezelda's body in the freezer thaws and makes a mess. A much better approach is apply fuel only to the top of the pole, flames are excellent conductors of electricity and 2400V with 600A behind it phase to ground arcs furiously. Make it look like arcing started a pole fire, you really don't want the fire marshal looking for an arsonist now do you? MUAHAHAHAHAAAaaaaaa...
"How that thing ever got Part 15 certification is beyond me."
You'd be surprised to learn just what Part 15 device radiated RF allows and doesn't take conducted RF into account at all. Many devices like wireless intercoms and alarms for example use RF conducted by mains wiring to communicate. That little bugger could be sending RFI through the wiring to the receiver and/or the wiring acting as a transmitting antenna.
Power company called; pole number given. We'll see how long it takes to get a response.
Update: The RFI guy from the power company (who, it just so happens, is a ham) called today. Says he found a guy wire that was touching the neutral. He made some temporary fix, but the line crew will have to do something more permanent. He also mentioned that he noticed another noise source along another street, but hasn't quite pinned it down yet.
While I had him on the line, I also pointed him in the direction of another noise source that cropped back up 3 days after I phoned in the original complaint. This source effectively wipes out any VHF SSB signal below an S7 when I'm pointed ESE and about 15-20 degrees either side of that. Gave him that pole number, and I suspect I'll have a call back in a few days.
Now, the ace card in my back pocket (well, a few aces) on all this is that I know the RFI guy. I've been dealing with him for over a decade. I also try to do as much legwork ahead of time. I've done this enough times that I've earned a reputation for coming pretty close to the mark. This saves them a lot of time and effort.
Five days turn around.... not bad...
w6tmi
09-18-2014, 10:43 AM
He has got a rubber penis, and he's not afraid to use it, bitches!
n2ize
10-23-2014, 02:45 PM
I don't think the people living in the house 60 feet away would appreciate that.
Especially when all the PCB oil spills out and the neighbors property turns into an environmental cleanup site and they have to deal with guys in moon suits digging up their property. And I am sure that transformet is filled to the brim with PCB oil.
KG4NEL
10-23-2014, 03:10 PM
Tree powerpole 1 gallon fuel wooooofff, problem solved.
I was thinking a few rounds from something of suitable caliber.
It'll get them out there, at least.
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions Inc. All rights reserved.