[time-nuts] 60 KHz Receiver
jimlux at earthlink.net
Tue Oct 5 09:58:04 EDT 2010
On Oct 4, 2010, at 10:26 PM, "Heathkid" <heathkid at heathkid.com> wrote:
> One more note before I just "read the posts for a while"...
>> a) broadcasts aren't legal for US hams
> Do some reading on telemetry and when broadcasts ARE allowed. I've been a Ham for more than 30+ years.
Telemetry is allowed only in the sense that it is to a specific recipient(s). That's sort of different from a beacon on hf... I don't know how the ncdxf beacons are licensed.. They may have a STA
But legality is the least of the issues.. If you set it up and you're not annoying anyone, I doubt you'll get hassled much..
>> b) ionospheric uncertainty in the skywave path makes this no better than WWV
> No kidding... but without GPS (and assuming no Internet as well) how do we sync our clocks besides RF?
The way it's been done for centuries... Astronomical or traveling clocks or wireline.
How close do you want to sync.. HF paths are probably only good to milliseconds.
>> c) Whats wrong with GPS and/or WWV and/or CHU or whatever?
> Nothing as long as they are TRANSMITTING.
Sure.. As an academic exercise I can see wanting to figure it out, and even doing it as an experiment for the thrill. But If wwv isn't on the air, I don't see hams stepping in to fill the need. And if it's self reliance,then a local atomic reference seems a better approach.
>> d) A cheap Rb would give you a local reference that is much better than what you could do with receiving something via skywave.
> I have three Rb standards to go along with my two Thunderbolts.
So you want to be able to sync your local ref to some other standard?
That is more of an ad hoc thing than setting up a beacon, etc.
>> If you want something that isn't run by governments,and is a technical challenge, how about pulsars? I'd guess (not having looked into it at all) that is would be cheaper to set up a station to receive pulsars than to run a Cs standard.
> Are you serious? Cheaper? Really? I'll trade you a Thunderbolt... complete kit! for a full Pulsar time/frequency reference receiving station that is reliable (and the real-estate plus equipment for a dish large enough for it!). ;)
Were not comparing to Tbolts here.. You suggested that someone connect a Cs to some stable transmitter, etc. I think an amateur pulsar receiving system is comparable to the Cs setup.
Now, if it's that you want someone else to put up the station, so you don't have to spend the time and money<grin>, You've got some selling to do...
> What time is it?
> *that wasn't my point* ---- it's "relative" and I'm not going to go further with this discussion. I just thought a "time-nuts based time system" was an interesting prospect.
It is interesting.. And figuring out how to do precision time/frequency in an infrastructure-lite environment is challenging, Especially if you want to do it in an adhoc way fairly quickly.
It might be cloudy/smoky. Gps and wwv might be unavailable because of interference, locally.
So there is value in thinking about it. What I don't think there is value in is someone trying to set up a wwv light using psk31 on a continuing basis. And that's just my opinion. There are lots of things other hams do that I think aren't particularly useful or valuable, just as there are things that I do ham-wise that others think are wastes of time.
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