mike742 wrote:
I've always noted with some curiosity that 77.503kHz,
60.002kHz, and 60.005kHz are off-the-shelf crystals too...
used in a direct conversion receiver for DCF/WWV to 3Hz, 2Hz,
and 5Hz carrier-detect frequencies maybe?

Strange. Maybe another resonance mode?

I'd guess the specified frequency is parallel resonance with
the specified load capacitance.

I have some Digi-Key SE3320-ND 60 Khz xctls (C-2 60.000KC-P).

My best try at measuring the series resonant frequency shows
59998 Hz. Perhaps the 60.002 Khz ones are series resonant at
60000 Hz. I don't have any of those to measure.

Here are some measurement of a few Epson Type 2 60 kHz crystals I made
recently:

Fs BW Fp
60001.6 4.6 60009.9
60001.2 4.6 60009.7
60002.2 5.6 60010.6
60001.1 4.4 60009.5

The test setup is shown below. The input signal was produced
by my homebrew function generator implemented with an AD9833.
The clock for the 9833 is an 10 MHz SG-615B which
has a specified frequency stability of 100 PPM.


|Vcc
|
|
20.0k |
Vi 0.1++ |-+ 2N5457
-/\/\-+--||-||--+-|
| ++ | |-+-- Vo
\ \ |
/ 1M / \
1.0k \ \ /1k
| | \
| | |
+---------+----+
|
V

"Watson A.Name - "Watt Sun, the Dark Remover"" wrote
in message ...

Or use the S-meter to see very low freq beats.

Check out the latest Atlanticon proceedings, or the upcoming issue of the
Homebrewer for a circuit to allow you to see zero beat to within a fraction
of a Hz.

...

["Followup-To:" header set to rec.radio.amateur.homebrew.]
On Wed, 27 Apr 2005 06:01:02 -0700, Watson A.Name wrote:

"John Woodgate" wrote in message
...
I read in sci.electronics.design that Tim Shoppa
wrote (in
.com) about 'wwvb
receiver chip needed', on Tue, 26 Apr 2005:

Zero-beat to WWV is hard to do better than 50Hz by ear.

Have you tried a Lissajou display?

Or use the S-meter to see very low freq beats.

S-Meter! On 'modern' gear?? All they give you is a bank of
eye candy in the form of leds.

But, yes -- I've used Real S-Meters to get Real Damn Close to zero
best in days past.

73
Jonesy
--
| Marvin L Jones | jonz | W3DHJ | linux
| Gunnison, Colorado | @ | Jonesy | OS/2 __
| 7,703' -- 2,345m | config.com | DM68mn SK

On 27 Apr 2005 16:04:33 GMT, Allodoxaphobia wrote:

But, yes -- I've used Real S-Meters to get Real Damn Close to zero
best in days past.

Well, ... "best beat" works, too.

Jonesy