[Lowfer] EAR & MP and noise management

[Michael Sapp]

Hi All: Afternoon captures of EAR and MP with favorable background noise for a change .....



https://www.dropbox.com/s/78l2afydw4ulcqq/EAR92715.JPG?dl=0

EAR Peaking around -57 and peak noise about -75 


https://www.dropbox.com/s/apxuxhvcjo847dc/MPLONSE1.JPG?dl=0


A bit quieter for MP's signal was peaking in the -42 ~ -44 range and peak noise -80 ....


I installed a new AC mains Low- Z ground and have finally re-worked enough ground connections in my house to have 

a very noticeable improvement from LF through the VHF/UHF range.  


New mains ground shown here...


https://www.dropbox.com/s/fhh1i49lr7e4em5/TTSGND.JPG?dl=0


https://www.dropbox.com/s/5imkztanj8mc3t8/IMG_4521.JPG?dl=0


https://www.dropbox.com/s/546b341kkvdoysh/IMG_4525.JPG?dl=0


https://www.dropbox.com/s/q5pxlrteb4whffv/IMG_4512.JPG?dl=0


    Past few days I completed my shack bus bar ground and got most of the computer equipment (PCs, router, FIOS optical head power supply , etc.)  directly grounded to the LO-Z mains ground with short paths in other rooms at my QTH.  The epiphany moment came when "sniffing" for FRO noise with my FT-817 and AM rubber duck at my MHz IF range for my LF converter.  I had a large binocular toriod stack on the FIOS supply AC line to reduce an adverse amount of broadband hash it generated. The FIOS supply is connected to a UPS that is very near the LO-Z copper flashing lead-in to the service panel. Touching a thumb to a screw on the back of the UPS and a finger to the copper flashing lead-in  "killed" almost all the FIOS supply noise the FT-817 was hearing as a noise sniffer.  I knew I had an effective ground at that point. So I grounded the UPS chassis to the LO-Z ground directly and made a mag shield for the choke on the FIOS supply and grounded it directly as well.  The FIOS equipment noise decrease was dramatic.  

Bead or toriod chokes on AC cords have a shortcoming of adding choking action to the ground wire as well as the hot and neutral. You get a noise reduction with that kind of choke arrangement, but it is not optimal.  When your AC mains ground is really LO-Z, the effect of grounding the device chassis directly and with a short path to the LO-Z ground let's the AC cable choke do it's job properly.  Instead of  20 dB noise reductions with just the bead or toriod chokes on the AC cable, the choking action is more like 40 or 50 dB---perhaps more.  That was a real eye-opener to experience.

 Then I did the same and made mag shields for the wal-wart supplies for both my Acer netbook computers I use for WSPR and ARGO. I have toriod chokes on those computer supplies which help, but their was still broadband hash being radiated and very noticeable with the FT-817 and rubber duck noise sniffer when the duck was within several inches of the supply.  A clip lead from my bus bar to the wal-wart mag shield took all that noise away as well as far as what my FT-817 noise sniffer can detect audibly.

Another telling sign was that previously I used to be able to hear noise with my FT-817 and rubber duck noise sniffer at the far end of my plumbing pipes -- like in the kitchen and basement sinks that are opposite from the AC grounding point connection.  Now there is no noise audibly detected along the plumbing system pipe what so ever with the new ground system.   So for the first time I can remember, all my AC wiring ground branch circuits and the plumbing system are no longer acting like antenna radials.  Likewise I am no longer hearing any "computer noise" in the 3 MHz range if I close couple the rubber duck on my FT-817 to my aluminum downspouts....

Of course, the down side to all this is I have unmasked other noise sources in my neighborhood that were being hidden by my own noise sources.  But at least I now have control over that which I can control.....

73,  Mike wa3tts