[volt-nuts] Stabilising resistors

[Dr. David Kirkby (Kirkby Microwave Ltd)]

I have bought some resistors of 0.1, 1.0, 10, 100, 1k, 10k & 100k Ohms.
These are in little boxes with 4 BNC connectors spaced 22 mm apart.

This sort of thing

http://m.ebay.co.uk/itm/231460477406

although I paid a *lot* less.

They are designed for use verifying the performance of LCR meters. I don't
know what the uncertainty of *impedance* on these are, but they are
probably optimised for use to 1 or more MHz rather than DC resistance
standards. At least one I bought is supplied with a 120 MHz LCR meter, but
the others are possibly designed for a lower frequency. Getting
specifications on these is not easy.

My HP 4284A LCR meter is at Keysight being calibrated.  My aim is to use
these resistors as a way of tracking drift in the meter which would
indicate it needs calibration.  The basic uncertainty of the HP 4284A meter
is 0.05%, although it is higher at very low and very high impedances.

Is there realistically anything I can do to stabilise these resistors? I
don't want to go to the expense of adding Peltier temperature controllers
to them.

I suspect the fact that they are several years old means that they are as
stable as they are going to be, but I just wanted to check if there is any
improvement that I could make. I expect thermally cycling these in an oven
and fridge would do more harm than good,  but perhaps I am wrong.

I do have a 3457A 6.5 digit multimeter which has not been in a calibration
lab for at least 15 years, although I have measured some 0.005% resistors
as a check for gross errors.  It would be worth tracking these HP resistors
with that too.

It is not worth paying commercial rates for calibration of the resistors as
getting the LCR meter calibrated at Keysight is not that expensive (£207
GBP). Keysight also agreed to provide me a software option 006 (support for
2 m & 4 m cables), so getting the meter calibrated was especially good
value.

Dave