interference

Status
Not open for further replies.

Your_account

Completely Banned for the Greater Good
Banned
Joined
Jul 13, 2013
Messages
1,261
Location
.AT
hwy guys i use an SDR Dongle to Receive Amateur-radio and i have huge interference (Picture).
So hat could that be?!
 

Attachments

  • Unbenannt.jpg
    Unbenannt.jpg
    106.3 KB · Views: 439

zz0468

QRT
Banned
Joined
Feb 6, 2007
Messages
6,034
...So (W)hat could that be?!

It's hard to say. It could be almost anything with a switching power supply and/or microprocessor. You didn't give us enough information to even speculate.

Is this audio baseband? IF? What frequency? The display says 437.2203 MHz. Really? Does it go away if you remove the antenna? What is the antenna? Is anything grounded? Is it grounded properly? What is the bandwidth of the waterfall display? The on-off pulses almost look like Morse code... equal sign or hyphen? More likely a micro processor type noise.

Details please. The picture is utterly useless without the narrative that should have come with it.
 

AgentCOPP1

Member
Joined
Nov 16, 2011
Messages
296
Yes, the picture is useless. It could be almost literally a million things. You gave us no information to go on.

If I were to take a wild guess, it looks like your computer might be struggling with the program. Never mind all of the random interference lines, from the looks of the horizontal shifting lines, it seems to me that the program itself is struggling. Might be a problem with too little RAM, other programs clogging up CPU resources, or a faulty dongle. But really it could be anything, but my suspicion is with your computer.
 

Your_account

Completely Banned for the Greater Good
Banned
Joined
Jul 13, 2013
Messages
1,261
Location
.AT

zz0468

QRT
Banned
Joined
Feb 6, 2007
Messages
6,034
Can you post a screen shot with a spectrum analyzer type display instead of the waterfall display? With an indoor antenna, you're quite likely getting interference from the computer.
 

WB4CS

Member
Joined
Feb 10, 2005
Messages
900
Location
Northern Alabama
Aliens. It's gotta be aliens.



It could be a TV giving off RFI. When my living room plasma TV is on, 445.575 on my radio gets a ton of noise. Turn off the TV and the noise is gone.
 

mikepdx

Member
Joined
Dec 19, 2002
Messages
854
Location
Corbett, OR USA
A thousand different things from poor shielding in absolutely
anything and everything cheaply engineered that generates RF,
to RF traveling along cables - ethernet, audio, home wiring.
Maybe a dimmer, fluorescent light, poor ground on powerco
xfmr, cheap CATV amp, loose or improperly installed
cable tv cables, blah, blah, blah.

Routers and ethernet cables are super common sources of
interference along with loose or improperly installed cable tv
coax fittings. They spew out all kinds of noise.

The tough part is that it could be in any of your neighbor's homes, too.

If only on one or several freqs,
Have you put that freq in a handheld and done a walk around???????

Are you using a laptop or PC with UPS?
If so turn off the AC main at the house.
That will eliminate many possible sources.

I'd bet you'd find all kinds of ideas on how to solve
interference problems by using the search feature
in the RR forums.
It's been discussed hundreds of times.


Good luck.
 
Last edited:

Your_account

Completely Banned for the Greater Good
Banned
Joined
Jul 13, 2013
Messages
1,261
Location
.AT
Have you put that freq in a handheld and done a walk around???????
i dont have any but when i shutdown my pc i can put the antenne on my tablet pc and check.
 

Your_account

Completely Banned for the Greater Good
Banned
Joined
Jul 13, 2013
Messages
1,261
Location
.AT
when i use the small antenna outside its the same noise.
 

n5ims

Member
Joined
Jul 25, 2004
Messages
3,993
Cable-TV channel 59 perhaps (due to leakage from a nearby CATV cable).
 

Your_account

Completely Banned for the Greater Good
Banned
Joined
Jul 13, 2013
Messages
1,261
Location
.AT
so i check it yesterday and my pc make that noise.
the huge problem is a cant close that pc the case is rubbish....
 

mrweather

Member
Joined
Dec 19, 2002
Messages
1,251
Maybe try wrapping it in aluminum foil (keeping the vent holes uncovered) to form a Faraday cage?
 

zz0468

QRT
Banned
Joined
Feb 6, 2007
Messages
6,034
So, now you know... computers generate RF noise. Placing a receiver right next to an open computer is going to cause the receiver to pick up noise. You need to do two things... separate the antenna from the computer, and close up or otherwise suppress the noise radiating from the computer.

In the snippets of sentence fragments you've provided us, we've managed to discern that you're on the first floor, can't use outside antennas, and are using an SDR dongle adjacent to the computer that has some sort of undefined "rubbish" open case issue.

Sounds like a recipe for failure to me, and you're not giving us much to work with to come up with suggestions. Good luck to you!
 

Ed_Seedhouse

Member
Premium Subscriber
Joined
Jul 10, 2010
Messages
570
Location
Victoria B.C. Canada
Try a ground loop isolation transformer. You can get them for around twenty bucks on the internet or you can make your own if you have some ferrite cores hanging around. The output of my computer had terrible noise on it when plugged into my stereo system, and this was completely eliminated by the transformer.
 

khooke

Member
Joined
Feb 19, 2013
Messages
54
Location
Davis, CA
assuming this is the pc that you're using with your sdr dongle, maybe you should read some reviews and shop around for a quieter pc? it's not a point that you'll see mentioned in most reviews, but that screenshot looks pretty terrible if you ask me, and if it's generating that much noise, it's obviously not much good to try and use it with your dongle?
 
Status
Not open for further replies.
Top