[Elecraft] OT: K3 timekeeping

[Fred Jensen]

Next time you have little or nothing to do, and have a P3, set the span 
to about 10 KHz, go to AM, and center any of the WWV's in the display. 
You *should* see:

1.  The carrier

2.  The 100 Hz subcarrier around it that carries the IRIG-H time code

3.  The pair of tone sidebands [if the tone is on].

What you *will* see depends on which WWV you're tuned to.  If it's 2.5 
or 20 MHz, the above pretty well describes the display.   If it's 5, 10, 
or 15 MHz, you will see:

1.  The carrier

2.  The 100 Hz IRIG-H subcarrier

3.  The pair of tone sidebands

4.  The second and third harmonics of the tones, maybe the fourth 
harmonic depending on conditions and strength of the signal at your QTH

5.  The 100 Hz IRIG-H subcarrier around the pair of tone sidebands and 
all the harmonics.

There is a single combined baseband that feeds all transmitters. 
Apparently, the 2.5 and 20 MHz transmitters are low level modulated with 
linear amplification.  The other three appear to be plate modulated 
class C PA's right out of the hamshacks of the 50's.

The difference is striking and surprising.  I've always thought NIST was 
the Gold Standard.  With a single tone modulating my K3 in AM, I see the 
carrier, the two sidebands, and essentially nothing else on a spectrum 
analyzer.  I sent screen shots and an explanation to WWV, and asked them 
about the transmitters.  The reply said, "We're pretty sure we're on 
frequency."

I have an extra Hamstack Microchip 18F46K22 CPU here looking for a 
project.  Maybe an outboard WWV [or WWVB] timecode demodulator that sets 
the K3 time [I assume that's possible via serial commands, didn't look].

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 50th Running of the Cal QSO Party 3-4 Oct 2015
- www.cqp.org

On 11/26/2014 4:15 PM, Phil Wheeler wrote:
> My watch is a Casio Pathfinder (barometer, altimeter, compass, and even
> keeps time!). It gets updated every night via Colo WWV station -- unless
> I turn on my TV converter from Time-Warner; then it does not update,
> even if the converter is 10 ft away.
>