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Posted: Wed Dec 20, 2017 6:59 pm
I am a longtime radio hobbyist but consider myself somewhat of a novice when it comes to some of the more technical aspects. I have an RSP2 and am getting a steady "chop... chop... chop... chop..." noise along with a lot of crackling static on almost all bands below 30 Mhz. Instead, I would expect to hear a smooth "hiss" when not tuned to a signal. I get the same thing even when selecting an empty antenna input. I've troubleshot by turning off all electronics in the general area around my setup. I then connected my RSP2 to a tablet but the noise persists. I'm also using a good quality USB cable with ferrite chokes thinking the noise might be getting in through the USB.
Posted: Wed Dec 20, 2017 11:16 pm
I found that I have some powerline adapters that I missed in my troubleshooting that is causing the noise. Is there any way around this (short of doing away with them)?
Posted: Wed Dec 20, 2017 11:25 pm
A couple of things to investigate. Do you have enough processing power? Lack of it can cause chopping, especially if you are using a high sampling frequency.
The other thing is to see if you are tuned to the same frequency as your local oscillator (LO). If you are, you may be hearing the soft pulsing of the central 'spike' as it cancels itself. Tune away from the spike to see if the chopping stops.
Posted: Thu Dec 21, 2017 2:46 pm
I don't believe processing power to be a problem. I have an i7 with 8GB of RAM. I typically only use a sampling frequency of 2 Mhz and I always give separation between the tune and the LO.
I'm pretty sure I've narrowed it down to the noise coming from a nearby powerline adapter. The noise goes away when I unplug it. Wondering if there's anything I can do to reduce the noise without doing away with the powerline adapter.
Posted: Thu Dec 21, 2017 4:09 pm
The best thing you can do is to put the PLC adapter into the trashcan. These kind of adapters belong to the worst noise generators I know. Powerlines are made for power and not for data transmission. They radiate the PLC-signal which disturbes your reception.
Replace them by WLAN or cable.
Posted: Thu Dec 21, 2017 4:29 pm
That's what I was afraid of. Thanks!
Posted: Thu Dec 21, 2017 6:08 pm
Horrible things, thought up by idiots who think hammering high-speed data onto a poorly balanced, unscreened cable network is acceptable.
A neighbour once had a pair given to him for his birthday and they completely trashed my listening from about 3 MHz to 12 MHz. As he's an OK bloke, I invited him in and showed him what they were doing. He was horrified and unplugged them the same day!