[TVARC] Fwd: [wsjt-devel] 60 Hz + harmonics sidebands on FT8 signals? (Paul Kube)

[Earle]

This looks interesting. 

Earl

Sent from my iPhone

Begin forwarded message:

> From: Jim Brown <k9yc at audiosystemsgroup.com>
> Date: August 8, 2019 at 2:16:41 PM EDT
> To: wsjt-devel at lists.sourceforge.net
> Subject: Re: [wsjt-devel] 60 Hz + harmonics sidebands on FT8 signals? (Paul Kube)
> Reply-To: k9yc at arrl.net, WSJT software development <wsjt-devel at lists.sourceforge.net>
> 
> The concept of a so-called "ground loop" is completely false. It has no basis in physics. The "buzz" we hear when equipment is not properly bonded consists of triplen harmonics of the mains frequency, 50 or 60 Hz, depending on where you live. What DOES couple this trash is the failure to follow proper engineering practice, which is to bond together the chassis of every piece of equipment in a system, to bond all grounds in a building, and to bond that combination of equipment to the combination of building grounds. (my friends in the UK substitute the word "earth" for "ground.") A second important part of good practice is to get power for all interconnected equipment from mains (power) outlets that have the same Green Wire (protected earth conductor), or whose green wires are bonded together.
> 
> When all of this done, the station is safe for lightning, and no "isolation" is needed.
> 
> Details of proper practice is at http://k9yc.com/GroundingAndAudio.pdf
> 
> 73, Jim K9YC
> 
>> On 8/8/2019 3:43 AM, Paul Randall wrote:
>> The point of the isolated interface is to prevent noise/hum caused by ground loops but if there is no ground at all, it is not only useless but actually causes a big problem. I can only assume that if I saw lots of 50Hz spurs on receive, there was a good chance they were there on transmit as well.
> 
> 
> 
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