[time-nuts] nubie querie

[jimlux]

Paul Boven wrote:
> Hi Tom, everyone,
> 
> Tom Van Baak wrote:
>> See: http://www.leapsecond.com/museum/pulsar for some
>> pulsar ADEV stability plots and links to many research papers
>> with all the details.
> 
> Your page starts with the question "if it was possible for an amateur to
> receive pulsar signals?". Turns out you can, at least the particular
> bunch of amateurs who have been restoring the 25m Dwingeloo radio
> telescope (http://www.camras.nl).

This, and similar impressive accomplishments, has prompted some 
lunchtime discussion at work (JPL).. One of us (N5BF) has been 
contemplating what it would take to do an amateur EarthVenusEarth (after 
some of his experiments doing EME with 5 watts)..

So, when talking about "amateur" accomplishments.. where do you draw the 
line on using "big stuff".  If you're an amateur who happens to have 
access to Arecibo or to a DSN 70m dish, is that *really* an amateur 
contact/event?

The same thing applies to timenuttery, to a certain extent.

So we thought.. if it's something that a single amateur can feasibly do 
single handedly.  Surely, no amateur is going to build Arecibo or a 70m 
dish in their backyard.. but wait, what if you're Paul Allen building 
the ATA at Hat Creek.  Should happening to be wealthy enough to buy all 
the toys exclude you.. after all, it's the "amateur" aspect, not the 
"poverty" aspect.

Or, maybe it's the "fabrication" of the equipment that's the relevant 
thing.  I know I'd be more impressed by someone building a Cesium clock 
from scratch in their garage more than just buying one off the shelf, 
even if buying one is cheaper.  Kind of like making your own vacuum tubes.

And, even, since those of us sitting around the lunch table do RF work 
of one sort or another for a living, is *anything* we do with RF truly 
amateur (leaving aside legalisms like pecuniary interests, etc.).

Maybe it's a sort of fuzzy definition.. you can fit it in a suburban 
backyard (leaving out the 70m dishes, but not the EME array, as long as 
you're not in the W5UN category)

Or time nuts wise, some aspect of self fabrication, whether it be 
hardware, software, or even just an unusual configuration or kind of clock.


> 
> Could you do this with a more modest antenna? The lesser gain would need
> to be compensated for by using as much bandwidth as possible (which
> needs de-dispersion), and folding the signal by the pulsar period.
> Folding in turn requires a stable clock, and compensating for the
> doppler shift caused by the Earth's motions. I would say that receiving
> the brightest pulsars is within reach of the bigger EME stations - but
> still working on the calculations (and demonstration) to back this up.

This is kind of fascinating...  When I got started in home time nut 
territory, it was because I got a Z3801.. as a coworker put it, how 
often do you have something accurate to way better than a part per 
billion in your garage.


>