Speaking of LORAN receivers, I have two Stanford Research Systems FS700 receivers here at work (in central VA) that I have been asked to dispose of. They both have ovenized oscillators, and I have one original manual. The antenna is on the roof, but I think it'll stay there ;-). Any offers for one or both?
73, geo - n4ua On Tue, Oct 5, 2010 at 8:57 AM, paul swed <paulsw...@gmail.com> wrote: > A great thread by everyone. Oh to make the loran receivers work. But that > is > indeed the past. Can not hear Europe on east coast. > But the question really is, what do you want to accomplish? I don't think > its a time stamp. Its just to easy to get it from GPS or the network. But > that could be a secondary use. I believe the primary goal would be > frequency > distribution with perhaps a tick. > If this is the goal then I am 100% in agreement that there are far more > efficient modulation and recovery methods today. The trick is you need > something that does not effect the accuracy of the timing and may improve > the various transmission issues at these frequencies. By the way this list > has a heck of a brain trust so its very very possible. > Someone mentioned spread spectrum. Thats very interesting as it is what GPS > uses and could work at these lower frequencies. > Like the "Hey this is just telemetry" comment. You know the FCC does > indeed > give temp authorization for quite long periods of time. Years in fact. > So I would be in the keep it simple mode. > Great a single carrier with a id every 10 min. Maybe that could be waved to > 1 per hour or 24 hours. Unfortunately then we have nothing better then > wwvb. > The modulation method may be key and then what freq we would use. BPSK at > higher frequencies is also impressive. > My first contact was in the indian ocean on 5 whats from boston. > Regards > Paul > WB8TSL > > > On Tue, Oct 5, 2010 at 6:59 AM, Bob Camp <li...@rtty.us> wrote: > > > Hi > > > > If you were starting from scratch there are a lot of things you could do. > > If the intent is to put out something a Loran receiver will recognize ... > > not so much. > > > > Bob > > > > > > On Oct 5, 2010, at 6:44 AM, Poul-Henning Kamp wrote: > > > > > In message <b69fdcaf-2b39-4575-b5cd-66a87fa1b...@rtty.us>, Bob Camp > > writes: > > > > > >> Even though it's pule, the RF power is way beyond the sub 1 W > > >> outputs currently contemplated on those bands. Signal to noise > > >> *does* matter. > > > > > > You know, there are other ways to skin that cat these days. > > > > > > Old-time signals had to be grossly inefficient because the receivers > > > were inefficient, in particular the "ear-wristwatch" kind of time > > > receivers. > > > > > > These days we have spread-spectrum modulation, and if our only goal > > > is to transmit a timestamp, you can spread pretty wide and far and > > > need very little power to produce a receiveable signal at long > > > distances. > > > > > > The QRSS hams are playing around with numbers like 17,840,000 miles > > > per watt, and all it takes to turn that into a time/frequency > > > services is a spreading function with a really good autocorrelation. > > > > > > Obviously, you will not get second by second measurements, but the > > > measurements you do get, say once per hour, will have much higher > > > precision because of the averaging that goes into them. > > > > > > And equally obvious: propagation effects will take their toll, but > > > still... > > > > > > Somebody with a license should try that on 137kHz... > > > > > > Poul-Henning > > > > > > -- > > > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > > > p...@freebsd.org | TCP/IP since RFC 956 > > > FreeBSD committer | BSD since 4.3-tahoe > > > Never attribute to malice what can adequately be explained by > > incompetence. > > > > > > _______________________________________________ > > > time-nuts mailing list -- time-nuts@febo.com > > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > and follow the instructions there. > > > > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.