We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissible in your locale.

Author Topic: Yet Another !&*%$! Noise Source  (Read 1011 times)

Offline ChrisSmolinski

  • Administrator
  • Marconi Class DXer
  • *****
  • Posts: 31165
  • Westminster, MD USA
    • View Profile
    • Black Cat Systems
Yet Another !&*%$! Noise Source
« on: November 29, 2016, 1333 UTC »
All the gory details here: http://www.radiohobbyist.org/blog/?p=1995

Here's the before / after waterfall:

« Last Edit: November 29, 2016, 1511 UTC by ChrisSmolinski »
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline ChrisSmolinski

  • Administrator
  • Marconi Class DXer
  • *****
  • Posts: 31165
  • Westminster, MD USA
    • View Profile
    • Black Cat Systems
Re: Yet Another !&*%$! Noise Source
« Reply #1 on: November 29, 2016, 1456 UTC »
I updated the blog post with the results of some more changes, further reducing the noise floor.
« Last Edit: November 29, 2016, 1511 UTC by ChrisSmolinski »
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft Horz skyloop / 500 ft NE beverage / 250 ft V Beam / 58 ft T2FD / 120 ft T2FD / 400 ft south beverage / 43m, 20m, 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline refmo

  • Marconi Class DXer
  • ********
  • Posts: 7829
  • Northeast Kentucky
    • View Profile
Re: Yet Another !&*%$! Noise Source
« Reply #2 on: November 29, 2016, 2203 UTC »
Nice work, Chris.
Noise is a constant battle, new sources are popping up in my neighborhood all the time.

While finding the noise source and eliminating it is the best solution, sometimes this is not possible (neighbors may not want to turn their Nintendo off, or they prefer to wear laundered clothing :)
If the noise is arriving via the antennas, this would be a great opportunity to test using phase control in the afedri to eliminate the noise.  This would only work best if both antennas are receiving the noise.
I'm also curious if this could eliminate the horrific noise from newer servo-motor washing machines.
If the noise if arriving via the power or usb port then this will not be much help.
Let us know the results if you try it.

I plan to purchase a dual-channel afedri in the near future.
Northeast Kentucky
Please eQSL to refmo[at]outlook[dot]com
Radios: Afedri AFE822x, Airspy HF+, RX-888, RSPdx, Tecsun PL880
Antennas: 700' Loop Skywire, Wellbrook ALA1530LN Loop, 400' Beverage, 34' Vertical, low dipoles on upper bands.

Offline jFarley

  • Marconi Class DXer
  • ********
  • Posts: 5922
  • near Chicago
    • View Profile
    • Email
Re: Yet Another !&*%$! Noise Source
« Reply #3 on: November 29, 2016, 2259 UTC »
Way to go!

Don't overlook the use of a common mode choke on the antenna;  many NDB DXers swear by them.  I use one out at any antenna which I will use for LF.  I use 40 T of RG174 on an FT140A-W core.  I ground the shield of the coax at the RX side of the choke to a ground rod located at the antenna, but some DXers say it works better in reverse.  YMMV.

Ain't LF fun?
Joe Farley, Near Chicago
SDR-IQ / R8 / R7
Remote Resonant Loops for HF and LF / ALA 1530
Active 60" Whip / PA0RDT
QSLS appreciated to:    jfarley44@att.net

 

HFUnderground T-Shirt
HFUnderground House Flag
by MitchellTimeDesigns