Re: [time-nuts] MH370 Doppler (Magnus Danielson)

2014-08-22 Thread Poul-Henning Kamp
In message <53f8060b.7020...@leikhim.com>, Joe Leikhim writes: >I applaud those applying their rather extensive math skills at >this problem, but from the outside, it appears to me that the problem >is so very complex (error prone) and so many assumptions are being >applied, that folks ti

Re: [time-nuts] MH370 Doppler (Magnus Danielson)

2014-08-22 Thread Joe Leikhim
You can probably find links to all of the data from the Duncan Steel Blog. You might start by looking at the questions the group has posed in an open letter to the ATSB and Inmarsat. Frankly, the data Inmarsat released appear to be rather scant and some believe to be doctored not RAW. I applau

Re: [time-nuts] EFC info on Trimble 34310-T OXCO

2014-08-22 Thread Charles Steinmetz
Bob wrote: The GPSTM is not as tweak friendly (no filter changes allowed) as some of the other GPSDO's. And that is a major problem. The correct filter settings for a Rb local oscillator are very different from the settings for an OCXO, which in turn are different from the correct settings

Re: [time-nuts] EFC info on Trimble 34310-T OXCO

2014-08-22 Thread Ed Palmer
Have you checked your X72 to see if it has the 1 PPS discipline option? That would be a lot easier (and probably better) than your proposed transplant. Ed On 8/22/2014 12:39 PM, Dave M wrote: Does anyone have any info on the OXCO in the Nortel/Trimble NTBW50AA-17 GPSTM receiver? The OXCO is

Re: [time-nuts] EFC info on Trimble 34310-T OXCO

2014-08-22 Thread Bob Camp
Hi All of the OCXO’s in the GPSDO’s pull 100’s (or more) times the pull of a Rb. The firmware that they have on that board for the OCXO is going to need some serious tweaks to get it to work properly with an Rb. The GPSTM is not as tweak friendly (no filter changes allowed) as some of the other

Re: [time-nuts] MH370 Doppler

2014-08-22 Thread Magnus Danielson
Time-error would be rings for sure. Doppler errors could also behave with these rings, but there is a much more complex scenario of ground speed and angle of observation. As the transponder passes under the satellite-earth line there is no observeable doppler, just like a train passing by has

Re: [time-nuts] EFC info on Trimble 34310-T OXCO

2014-08-22 Thread Bob Stewart
I've been using one for over a year.  They take 12V to power, and they have a VRef output around +6.25V, which implies an EFC range of 0-6V.  Unless you get one that's aged out, an EFC range of 0-5V should be fine.  The VRef has a bit of 10MHz on it on mine.  All in all, it seems to be a good OC

[time-nuts] EFC info on Trimble 34310-T OXCO

2014-08-22 Thread Dave M
Does anyone have any info on the OXCO in the Nortel/Trimble NTBW50AA-17 GPSTM receiver? The OXCO is labeled as Trimble 34310-T. I see some Trimble 34310-T oscillators on Ebay with pinouts labeled, but no other info. Specifically, I'd like to know the EFC characteristics for it. I'm thinking