[time-nuts] BPSK Receiver & GPS Antenna siting

[J. Forster]

Bob,

Thanks for the nice, concise, summary of the screwing the new WWVB format
will inflict on the timing community, especially because LORAN-C is dead.

The only "benefit" to the NIST/XW scheme I can see is creating a monopoly
for Xtendwave in precision TOD marketplace for those not relying on GPS.

When, due to governmental action, people are thrown out of a job, the
government often funds millions and millions in "retraining",
"outplacement" and other forms of aid.

IMO, the very least the government, NIST specifically, could do is provide
a vetted design so that the installed base of receivers will continue to
function.

YMMV,

-John

===============


> Hi
>
> Ok, to *try* to bring this back together.
>
> There is indeed a valid Time Nuts need for something other than GPS. In
> reality there are many reasons. One that has not been mentioned is to
> check on the validity of your long term GPS time estimate Small errors
> that accumulate can be a really nasty thing 

>
> If you live in the mainland US, there aren't a whole lot of alternatives
> to WWVB. Propagation is a reality that no amount of wishing will
> eliminate. HF isn't going to do you much good. Other LF signals just
> don't get here in any sort of useful condition.
>
> The only rational way to get time information off of WWVB is to look at
> carrier phase over many days. We have decades of information about that.
> Unless they implement a fancy modulation scheme (which they very much >
> have not) we are stuck with phase.
>
> Making this all happen (or not) with legacy gear is an independent issue
> of the basics above. I believe that if you can extract phase by some
> technique, you can re-broadcast a signal that the old gear will work
> with. Maybe it's easier that that, I hope so, but have not proven that
> by doing it.
>
> IF you want to simply do a new phase tracking receiver, there are a lot
> of bits and pieces you can use. None of them are terribly expensive.
The
> "radio" part of the system (not the antenna, not the frequency standard,
> not the other boxes that input to the system) likely can be done for
> $50 in raw parts. Weather that's a $5,000,0000 receiver or a $200
> receiver depends on your markup.
>
> Back when I bought them new, *none* of the legacy WWVB receivers cost
> $200. I don't remember any of them being much under $2,000. Would I pay
> $2,000 for one today? Nope, no more than I'd pay the same for a Loran-C
> receiver. Just for the record, I wouldn't pay $2,000 for a GPS either.
>
> Would I dive into a receiver project *before* we see the patent
> filings? -
> no. I'm not independently wealthy. Financing the challenge(s) to the
> likely stupid series of patents isn't something I want to fund. Easy or
> hard technically has nothing to do with it. It's not worth going broke
> for
> 
.
>
> Bob