Interesting noise spectra.

Opinions? Bit of a head scratcher for me. Broadband noise (thankfully not continuously) with a pronounced dip where I expect the band filter to be... or is it? Same with tuner in or out, even on different antenna (different levels, of course).

Not so much interested in the noise itself, but why/how the band cutout works. Fascinating stuff!

George Molnar, KF2T, Elmer

1652 Posts
600 Reply Likes
curious

Posted 3 years ago

3 years ago

AH0U

339 Posts
50 Reply Likes

That is an interesting screen shot showing the call sign too... What software is that??

Comment

3 years ago

David Decoons wo2x, Elmer

1369 Posts
293 Reply Likes

Looks lie SmartSDR for IOS on either iPad or iPhone

Dave wo2x

Comment

3 years ago

AH0U

339 Posts
50 Reply Likes

Nice

Comment

3 years ago

Mike Aust

11 Posts
0 Reply Likes

Yes, I have seen this before, you just found the band edges of the band filter for 20meters

Comment

3 years ago

KY6LA - Howard, Elmer

3737 Posts
1600 Reply Likes

That is Dogparksoftware for Mac ...Noi SmartSDR for iOS.

Comment

3 years ago

George Molnar, KF2T, Elmer

1652 Posts
600 Reply Likes

Well, now that we've confirmed I'm using DogPark SDR (highest praise to developer Don)... Still wonder why what appears to be the band filter effectively removes some of the noise level? With the noise absent, I see essentially a flat (within the expected characteristics of my antenna) noise level over the same spectrum.

Unless the noise itself is lower around the ham band, it's odd...

Comment

3 years ago

Mike Aust

11 Posts
0 Reply Likes

Besides the Passband Filter I suspect a different algorithm is in place for the
in-band ham band passband is taken into place & consideration (sampling versus BW, etc )
Only the guys at Flex would know !