[time-nuts] synchronization for telescopes
Heinz Breuer
hbreuer at debitel.net
Thu May 5 05:18:56 EDT 2016
Hello,
sorry I am late.
As I understood a transmitter was not considered as there is no ham licence. I don't know in which country this will be used. Many countries offer an entry level licence which is very easy to obtain. If you have a ham licence from one country many countries have reciprocal licence agreements. In many countries you just put the local prefix ahead of your callsign. My own callsign is DH2FA if I want to operate in France I just use F/DH2FA or HB9/DH2FA in Switzerland.
OTOH there are various ISM bands which can be used without any licence, 27.12MHZ, 433MHz, 2.4GHZ, 5.7GHz come to mind. With a directional antenna it is no problem to cover several Kilometers on 2.4GHz or 5.7GHz
The telescopes are probably not in a densely populated area and interferences with home based WLAN or video should be no problem.
vy 73 Heinz DH2FA, KM5VTa
Von meinem iPhone gesendet
> Am 05.05.2016 um 06:00 schrieb Chris Albertson <albertson.chris at gmail.com>:
>
> This is one of those "slap forehead" why did I not think of this. However
> you have just given the developers of the post processing software a BIG
> job. The distance to every transmiter to every telescope is different.
> So what you have is a mesh of telescopes and transmitters and finding a
> best fit is going to take some work. But I think you'd get order of
> magnitude better data if you did as you say and digitize the entire band,
> every station. But wow, some one will need to identify each transmitter
> based on frequency and look up it's location and time align one
> transmitter at a time. You can't time align the band as a whole.
>
> And again I don't thing you need to do this 100% of the time. You could
> periodically record 100ms chunks.
>
> You need a large computing facility for post processing or be willing to
> wait.
>
> ANY radio transmitter that all telescopes can receive is good. Might as
> well pick the loudest things around, AM and TV broadcast.
>
> There are a number of SDR "kits" on the market that can sample the entire
> band or maybe 2 to 4 TV stations. TV stations might be easier because TV
> is channelized.
>
>
>
>> On Wed, May 4, 2016 at 3:36 PM, Bob Camp <kb8tq at n1k.org> wrote:
>>
>> HI
>>
>> These days, there is no need to “just use one” if you are talking about AM
>> stations. Digitizing the entire AM band is pretty
>> a pretty low end SDR task these days. Storing the result will take some
>> storage, but noting insane;
>>
>> 100 Msps @ 16 bits => 200 MB / sec.
>> Run overnight: 30K sec
>> Total on the disk at each end: 6 TB.
>>
>> Yes, that’s a not a trivial disk, but it is hardly a “break the bank” sort
>> of thing.
>
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