[time-nuts] Effects of noise on EFC line? - Resolved

[Hal Murray]

bob at evoria.net said:
> So, I may throw another cap on it, but it seems to be clean down to what I
> can measure at the OCXO on my old Tek 455 with an X10 probe. 

Another thing to consider when chasing that sort of problem: How much are you 
picking up with your scope probe and/or its ground wire?

The classic home brew better-probe is to use a chunk of 50 ohm coax feeding 
into scope with a 50 ohm terminator.  (You get 2 of them if you cut a readily 
available connectorized cable in half.)  Insert 950 ohms at the probe end to 
get higher input impedance at the cost of a 20:1 divider.
  http://www.signalintegrity.com/Pubs/straight/probes.htm

It usually requires soldering at the DUT.  For me, it also requires a mental 
shift.  You have to think of your scope probe as a consumable rather than 
something that won't wear out if you take care of it.  A chunk of coax will 
last a long time.  Just cut off another 1/2 inch when the end gets too 
mangled.


-- 
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