[ARC5] Measured freq. stability of a BC-221 Frequency Meter.

[Leslie Smith]

G'day list-readers,

I measured the frequency of a BC-221 heterodyne frequency meter over an
afternoon, in 2006.
I posted the result in the Yahoo Group files for the Yahoo group
ARC5-radio.  See BC-221, frequency stability.XLS

For more detail about the record, move your mouse pointer over cell A1.

I reproduce the content of that cell here:  
2006/09/17  <- date of observation.
Notes about measurement of freq drift in BC-221 hetrodyne freq. meter.  

(1) Measuring instrument:  Fluke 1912A Multi counter.  (see note 1 for
more detail)
(2) Condition of BC-221.  Ser. # not given here.  The instrument is
believed to be in original condition; the set has not been re-capped (to
my knowledge).
(3) Environment.  Results reported here were recorded by connection the
Fluke to the output of the BC-221.  Manual record was made, the table
was transcribed to this spreadsheet by hand.

Gen Obs.  Since the measurements were made in spring, the minimum freq.
observed at 15:30 is consistent with the warmest part of the day.  From
this I infer the main cause of drift may be temperature - althought one
might also explore the possibility that the minimum coincides with some
fluctuation in mains supply.

Note 1.  Condition of Fluke frequency meter.  I purchased this
second-hand.  The circumstances of the purchase lead me to believe it
had been used in a laboratory, then - I presume - discarded due to age,
as that is the fate of most laboratory gear.  A manual came with the
meter.  There is has no calibration history available to me.  The manual
does state the worst case expected drift - due to crystal aging. 




-- 
73 de Les Smith
  vk2bcu at operamail.com

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