Mike,
Maybe I wasn't clear on this. I said it was "accurate to 1 Hz ... at
the calibration temperature." That says nothing about what happens as
the temperature *changes*.
+/- 0.5 ppm (or +/- 1 PPM) is the most common high-stability reference
option available for ham transceivers, K3 included. (And yes, this
applies to the entire temperature range, not per degree C.)
The K3 has an advantage over most transceivers in this regard. The REF
CAL menu entry can be used to enter frequency-vs.-temp data that's
supplied with each individual 1 PPM oscillator. This data is used in
conjunction with an accurate temperature sensor to fine-tune the
reference in 0.2-Hz steps as the temperature changes. So we're actually
expecting something like +/- 0.2 ppm over temperature. But we're
specifying it conservatively.
73,
Wayne
N6KR
On Aug 29, 2007, at 9:29 AM, Mike S wrote:
At 11:59 AM 8/29/2007, wayne burdick wrote...
49.380 MHz. All signal sources are phase-locked to the refernce. Fine
adjustment occurs in firmware, and once calibrated, it's accurate to
about 1 Hz through 6 meters at the calibration temperature. The
high-stability option is at the same frequency, with firmware
correction to better than 0.5 ppm.
49,380,000 * 0.0000005 ppm = 24.69 Hz, and actually worse on 6 meters,
since it's a higher frequency. In any case, it's considerably worse
that the 1 Hz stated for the standard reference. Is that ppm/degree C,
over some temperature range, or ? Is the tempco specified for the
standard reference?
---
http://www.elecraft.com
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