Some 34420a short readings

[martinr33]

I warmed up a 34420a nanovolt meter, and ran some stats on some shorts I made.

The "copper" short is built wit the Lemo nut connector and CdSn solder.
Cheapie #1 and Cheapie #2 are built with Lemo push-pull connectors and regular solder.

All three shorts show similar noise levels.
The copper pins short averages 2nV. The meter is well over a year out of calibration, but this is still pretty good. Or I have a "lucky" short.
The simpler shorts have similar noise levels to the copper short, but show an offset of 22 or 35 nV.

I did not control the number of readings, so these sessions ran several hours each in a non-temperature controlled environment. That likely boosted the spread on the copper connector.

The main takeaways for me are:
      The non-copper pin connectors are fine to use in many cases but you must compensate for the offset.
      The push-pull connectors are convenient, but you still have to wait for the thermals to settle so you don't get shorter cycles. Plus, the connectors likely take a bit longer to stabilize.
      There might be a small thermal offset at the connection pins in the meter.

(the push-pulls are also 1/10 the price of the copper nut connetcors).
     


         Cheapie #1      Copper   Cheapie #2
Average (nV)      35      2.0         22.1
SD             2.9           3.7           2.7
P-P            22.7        25.7         19.2
Min            22        -10.9         11.9
Max            44         14.8         31.1
Readings               5109    11824          2449