Observation 2245238: NAYIF-1 (42017)

Regarding Observation 2245238

Any thoughts on the interference at my location? The darker blue banding is very patterned and I see it across many bands (though it visualizes a little differently in each affected band).

It’s difficult to say for sure, but from what I see in that observation it’s going to be a combination of things.

There’s clear intermodulation distortion issues visible at ~100 seconds - you can see what appears to be a short FM transmission (possibly a local repeater, or some other amateur radio operator).

The vertical (well, doppler ‘corrected’) lines are probably a result of some kind of local interference - this could be anything from a poorly filtered USB supply (not necessarily the one powering your RPi!), to a HDMI cable (these can be surprisingly bad), to even a badly filtered LED light. Your best bet here is to go around and switch as much as possible in your house off while observing the SDR output using something like SoapySDRServer and CubicSDR (see this page for info on how to set this up: https://wiki.satnogs.org/Omnidirectional_Station_How_To#Setting_the_gain )

The large bands of increased noise again could be the same kind of sources as above. At my house I found a few very poorly filtered LED lights that would raise the noise floor on multiple bands quite significantly. I ended up replacing them with decent quality Phillips globes and the problem went away.

Hi @vk5qi, thank you very much for your detailed response.

A few months ago on the previous version of satnogs client, I did attempt to hunt for the source of this. I turned off all of the power in the house and was not able to find an inside source of this, so it may very likely be a neighbor’s house (I have my suspicions on a neighbor’s cheap solar microverter array).

I do have an FM stop filter and a wideband LNA.

I guess I’m going to have to keep trying to see if my house is adding to this.

How about this one?


Do you think the interference is the same? Looks a little different to me.