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CQ Noise experts!

For the last few months, normally in the afternoon, but not everyday, I get a dreadful noise appearing between 14.281-14.2866.

At its strongest (-92dBM)is on 14.285100. The source is not the equipment here as I have checked. Its sounds like a pulsating mains hum. Today it was going between 1500-1630Z and as before suddenly stops.

Has anyone in the UK had a similar experience?

Does anyone know what sort of equipment would ‘land’ a harmonic on this frequency?

Any useful comments appreciated.

Thanks
Mike

In reply to G6TUH:

I don’t know, but not all noise sources are from this planet. See for example the sound samples from Radio JOVE project

http://radiojove.gsfc.nasa.gov/observing/sample_data.htm

For obvious reasons the 14.00 - 14.35 MHz band is normally not used for radio astronomy. Closest band for astronomy is 13.36 - 13.41 MHz.

73, Jaakko OH7BF/F5VGL

In reply to G6TUH:

Why not post an audio sample? 14.285Mhz is a standard oscillator
frequency but I’ve no idea what it’s commercial application is.

Is its frequency fixed? Is it broadband?

Could it be some sort of packet data mode?

In reply to G6TUH:
The ARRL noise source pages can be useful in determining sources of noise.
http://www.arrl.org/sounds-of-rfi

Does your noise match any of these?

Regards
Pete (who purposely makes for the hills for a noise free environment!)

Thanks to all for your answers.

I think I know what it is ( a nearby TV, not mine!)and it sounds very similar to this.

I now have to get my old Yupiteru scanner out of retirement and start walking about the village.

Mike

In reply to G6TUH:

I find the FT817 with the 6 metres rubber duck is great for this job - I know exactly where in the neighbours house his plasma TV lives - fortunately they don’t watch a lot of TV except for the sport programs - which, of course, are mainly of a weekend!

The joys of living in an urban environment…

73

Brian G8ADD

In reply to G8ADD:

Hello Brian, just been testing the sensitivity of the Yup scanner - with the standard antenna it is quite deaf. I will have to use the FT897D.

I wouldn’t mind if I was urban but I live in a rural area, on a hill, overlooking a valley. The batteries for the 897 are all charged up - the other day I cut off the power supply to the house to see if there was something in the house generating the noise and listened on the 897 ~ so ready to go.

73
Mike G6TUH

In reply to G6TUH:

Good luck, Mike!

But what will you do when you find it?

About 6 years ago, I tracked down the source of a terrible noise (24/7) to the power supply of a cheap supermarket TV set two doors down the road. The neighbour would not allow me anywhere near his set and he and his wife have been “not speaking” to me ever since! The noise ceased after 4 years when his set finally blew up and he bought a new one.
:slight_smile:

73,
Walt (G3NYY)

In reply to G6TUH:

I have read of cases where the noise from a plasma TV was detectable a kilometre away! Modern ones are less noisy, but hopefully they will all in time be replaced by LED TVs.

Your 897 will get you to the general area of the source, after which a deaf scanner will pinpoint it for you!

GL Brian G8ADD

In reply to G3NYY:

In reply to G6TUH:

Good luck, Mike!

But what will you do when you find it?

A good question and one I have thought about. Right now I will not do anything but just locate. If the noise becomes 24/7 then I will have to knock on a door and hope that I can persuade the owner that their equipment would work SO much better with a few mods :wink:

73

Mike G6TUH

In reply to G6TUH:

Better to locate it, keep a logbook, and use OFcom’s services, I’m told that they can be quite helpful, particularly if you have already located the source for them.

73

Brian G8ADD

In reply to G6TUH:
Hi Mike

A few years ago I had terrible QRM across most of the HF spectrum but peaking around 5MHz. As Brian mentioned I used my 817 with it’s 6M helical aerial and tracked it down to a neighbour’s kid’s fridge which he keep in his room. It appeared the noise was being induced back into the mains wiring which was acting as a pretty good radiator.

Having pointed this out to the neighbour I said that they didn’t have to do anything as I would come up with the solution. I ordered a couple of mains filters from RS and fitted them into single 13A MK Type holders (about 50mm depth)with extension lead (1M)and plug. I gave one to the neighbour to fit between the wall socket and the fridge. Problem solved.

A few months later the neighbour gave me the the lead back, stating that it was no longer required as like Walt’s problem - the fridge had given-up-the-ghost!

Todate I haven’t had to use either of the leads, but there there just in case?

Now how to get rid of data noise - pops, purrs, squeaks, wow-wows, meows etc! Oops now where did I leave the cat?

Cheers

Jack (:>J
GM4COX

PS: The 817 is also great for tracking down car bourne noise and where it is eminating from. Now solving it in modern cars - that’s another problem - hi!

In reply to G6TUH:

Hallo Mike,

perhaps you’ll find something here:
http://www.iarums-r1.org/

73, Alfred - DJ0GM

In reply to GM4COX:

Not to mention the Orla’s!
73
Mike

In reply to DJ0GM:

In reply to G6TUH:

Hallo Mike,

perhaps you’ll find something here:
http://www.iarums-r1.org/

73, Alfred - DJ0GM

Hello Alfred, thanks for the link - very interesting.
73
Mike G6TUH

In reply to F5VGL:
The Radio Astronomy is a “listening” (passive) service; it can’t produce interference. If uses or not the 20m band doesn’t make any difference for us. We are an “active” service (we are transmitting). Indeed, the astronomy band is lower then amateur radio band because there are the signals of interest for them.
But, mostly probable the noise in discussion come not from other planets, but from somewhere in neighborhood.
73 de Dan

The source of the noise 14.285 +/- was from a neighbour located about 50 metres from my SteppIR vertical. The vertical is about another 50 metres to the shack. My neighbour Richard is a retired banker and is married to a woman from Hong Kong. They spend 4 out of 12 months in HK. They came back 3 months ago. His wife bought an electronic organ (China) and has a practice every afternoon. When I first started talking to him about “noise” he thought I was talking about her playing! We had a chat over a cup of tea. Richard did not quite understand what I was on about. Hopefully she will get bored and sell the organ along with its ( I suspect) RF generating power supply unit. So I have to live with it until then…

Mike
G6TUH