G8JNJ

Hmm, that look like interference too.

If you zoom out you can see lots of reguarly spaced signals that are almost certainly local interference.

I'm not saying that it isn't genuine, but I'm still not convinced.

The 15-25MHz region is generally fairly quiet and you don't hear many genuine signals unless propagation is good, especially wihen using a Mini.Whip type antenna, as they typically run out of steam on frequencies above anout 10MHz. This frequency range is also prone to Ethernet and other computer related interference, and the signals can sound modulated and come and go like genuine signals, depending upon what data is flowing at the time.

When you hear modulation on this frequency your KiWi, does it exactly match the other KiWi ?

Regards,

Martin - G8JNJ

Can you hear it on any other KiWi's that are near to you ?

If you can't, it's likely to be local interference, especially on the higher frequency bands.

Regards,

Martin -G8JNJ

@ Lonecrow

Looking back over some past notes, I think it's likely to be noise from Ethernet data. I was reminded about this when I tried my KiWi around 18MHz and found some weak signals similar to what you are observing, as I'd previously manged to reduce these to a fairly low level.

http://forum.kiwisdr.com/discussion/778/noise-at-roughly-60-khz-intervals

If you look at some of the screenshots that I'd attached to my post, they look a lot like what you are seeing and hearing.

The exact frequencies at which some of these signals are strongest will depend upon your Ethernet cable lengths and any switch / hub you are using.

Make up some simple 'sniffer' probes to use with your KiWi in order to locate local noise sources.






Copied from Keith Armstrong's excellent EMC notes.

http://www.compliance-club.com/archive/keitharmstrong/emc_testing1.html

http://www.compliance-club.com/archive/keitharmstrong/emc_testing2.html

Regards,

Martin - G8JNJ

@Hugobmf

I have just tried editing and saving a configuration on the admin pages and it worked OK for me running v1.216

When you enter a new value in to a text box, and then press 'enter', do you see the text box turn green for a short period ?

Regards,

Martin - G8JNJ

Should have said, these are the bursts centered on 4785KHz

See

http://www.hfindustry.com/meetings_presentations/presentation_materials/2017_sep_hfia/presentations/THALES_HFXL_HFIAsept2017_Presentation_final2_Bernier.pdf

Regards,

Martin - G8JNJ