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BK Precision 1856B Price Question


Homer J Simpson:

I just won this BK 1856B 2.7GHZ frequency counter on Ebay for $122. I really did not think I would get it.

This seller had another one listed for $250 OBO.

There is another one currently listed for $1250.

I found one currently being sold online for $1250.

Provided it works do you think I got a good deal?

Any experience with this model?


Its a very capable counter for what you paid for it, assuming it works.  Counters can be very economical today, what makes a big difference is the overall accuracy and any added measuring features [ A/B comparisons, statistics etc.,].   Crystal oscillators can give variable accuracy even with the best options, but temperature compensation is better than none, and ovenized is better still, but a lot depends on how its done, thus some models excels over others.

Counters are better if they allow options for external references that are stabler than its internal ones, and as the future makes available, an option this counter doesn't seem to have.

The spec sheets say this BK does about 2ppm accuracy.   Here the link is about the counter achieving 1-10 ppb with the counters native oven oscillator and later with a Rb oscillator taking it to 10-100 ppt.  Although references could be superb, its also vital how the counter circuits use the oscillator.  Also, specifying accuracy needs to specify the period, so for this quickie note, I can't tell if they are all the same, is that 2ppm per day? month? year?  Also, the same holds for the discussion linked here; what is quoted is not for the same time period.

The top option for users today is a GPS disciplined oscillator to bring it to 1 ppt or thereabouts.   For reference, the current US standard is stability to 0.01 ppt in its atomic clock oscillator.

A guideline on increasing accuracy versus type of oscillator reference:

And the range of drift over time of each standard:


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