Jeff Liebermann wrote:

Many switching power supplies run at about 60KHz. I have one
somewhere around my computer/TV pile, which kills WWVB reception if I
get anywhere near it.

Exactly, how many people have one?



Most WWVB devices have an indicator on the LCD display to show that
the clock was recently synced with WWVB time. My weather stations and
assorted digital clocks all have this feature.

What's recent? 1 minute? 1 Hour? 1 Day? a Week?


It's my understanding that only the modulation scheme will change, not
the encoded data. A universal chip that works using both system
should be possible without a major price jump.


Well no. The data is the same, but a new receiver needs to be used.
The old one just did on/off for an AM pulse, the new one uses BPSK,
which is two tone modulation. So not only does it have to decode
the carrier being there at all, it has to decode two different tones.

Then you have to decode the BPSK stream to get the data. This not a big
deal, you could do it with a sound card and a microprocessor, but it's
a different receiver design, and reprograming the microprocessor.

The kind of thing that if you really were going to sell 50 million of them
you could do it for a few dollars a chipset/board, which is probably what the
current ones cost, but if you want to break even with 10,000 you have to
sell them for at least $100, maybe more.

It's like I saw an article about an Israeli startup that had sold 200,000 of
their product. The article was entitled "sales of xxx disappointing".
I guess they planned on selling a million of them. :-(


I'm a bit mystified with the "new type of PM receiving antenna"
mentioned in:
http://www.nist.gov/pml/newsletter/radio.cfm
I didn't know that antennas were modulation specific.

Where have you been the last five years? I surprised that you have not
been swamped with HDTV antennas. :-)

I expect it's another gimick to say you need to buy a higher gain antenna,
or that's why your device can't sync. I expect that everyone will need
to buy 1/2 wavelength end fed wires.

(for the humor impared, that's a joke, a wavelength is 5 kilometers).


Geoff.
--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379
In 1969 the US could put a man on the moon, now teenagers just howl at it. :-(