Re: ATM Atomic clock stuff...

[Andy Wallace <andywallace@home.com>]

Jack--

I stand corrected-the propagation time just might be as long as one hundredeth
of a second for a thousand mile trip-you would indeed lose more time at the
receiving and processing end. What amateur astronomy application needs better
time then this?

Clear skies,  Andy  K5VM

Jack Brindle wrote:

> >I may be missing something here, but I think the signel from WWV travels
> at
> >186,000 miles per second. I don't think transmission delay would be a
> factor in
> >most applications. You do the math --from Colo. to your location.
>
> Andy, of all peopol you should realize the error in what you said. The
> signal doesn't travel in a straight line that distance, but rather it
> bounces off the earth and ionosphere to get where it goes. This adds a lot
> of distance (and time) to the signal. How much is hard to say, but it at
> least doubles things.
>
> Also, light and radio waves travel at 186,000 mps in a vacuum, but somewhat
> less in all other media, including the earth's atmosphere. Not much less,
> but it is a bit less, depending on the velocity factor of the media. Again,
> it would be difficult to say what the velocity factor of the atmosphere is
> at any given moment due to changing weather conditions along the path, etc.
>
> Your whole point is well taken, though. There won't be very much delay in
> the signal as it traverses its way to the receiver. The processing delay in
> the receiver (filters, etc), will probably match the signal's propogation
> delay.
>
> I have to agree with Jeff on the need for absolute accuracy in this
> particular application. Is it really necessary given all the other
> variables and tolerances involved in astronomical observations?
>
> Now, let's get back to the topic...
>
> -Jack Brindle
> ham radio: wa4fib
> ===================================================================
> "My name is bud lightbeer. I come in pieces!"