[Lowfer] frequency counter calibration

[Bill Cromwell]

On Fri, 2013-01-25 at 12:53 -0500, Douglas D. Williams wrote:
> I found an old Optoelectronics hand held frequency counter, model 2810,
> that I had almost forgotten I owned, in a drawer in my "electronics junk
> closet". I remember buying this new probably ten or more years ago. The
> built-in NiCad battery pack would no longer hold a charge, so I found a
> replacement on Ebay for $16 + shipping. Got that soldered in and the
> frequency counter is again operational, but I question it's calibration
> after all these years. After contacting Optoelectronics, they want $75 plus
> return shipping to calibrate it. "Calibrating" it simply involves supplying
> it with a known frequency standard of 10 MHz or greater and turning a small
> screw on the front of the unit. It doesn't even have to be opened up.
> 
> Any of you gentlemen who own a GPS referenced 10 MHz or higher frequency
> standard willing to "do a Bro a solid" and calibrate this unit for me? I
> will of course ship it to you and include return shipping costs in the box.
> I have the manual and a suitable oscilloscope probe for connecting to your
> frequency standard source.
> 
> 
> 73, Doug KB4OER

Hi Doug,

In my Opto frequency counter (and most of my other gear) the xtal
standard is operating at 10 MHz (or 10 MHz is one of the harmonics).
There are several ways to zero that against 10 MHz WWV. WWV is operated
by NIST and it *IS* the standard. You can tune to WWV with an AM
receiver and zero your Opto against that. You can use a different
standard (the Calibration oscillator - a secondary standard - in your
receiver) and beat against that (after checking the calibration of your
secondary standard against WWV). It's so easy that even *I* can do it.

73,

Bill  KU8H