[time-nuts] Re: Coupling between oscillators -- an example

[John Ackermann N8UR]

On 3/25/22 19:22, ed breya wrote:

> I'm a firm believer in using signal isolation transformers where needed 
> and practical. I've had plenty of issues with ground loop interference - 
> usually from line frequency harmonics - especially between different 
> pieces of equipment, but it can show up internally too.

It seems like isolation transformers are a coin toss between helping, 
doing nothing, and sometimes actually making things worse.  I think the 
problem is there are so many possible ground paths via power wiring, or 
even chassis bolted to racks, that one size very much doesn't fit all.

Another interesting thing is that this situation was easy to spot 
because of the significant frequency differences that made the beat 
period fairly short.  If these guys had all been within 1e-10 of each 
other, the trouble might have been harder to spot.