[time-nuts] New NTBW50AA

[Bob Camp]

Hi

1) Have you done a 3 day long survey at any of the locations? You need to do that to get the errors down. 
2) Fiddling with the gain and filter settings on a NTBW50 isn't useful. The unit does *not* work the same way as a TBolt. Just leave them alone.
3) Because of the way the uint works there is *no* way to translate the LH display to frequency stability. 
4) The OCXO in that unit is at least as good as a typical MV89. Since you have no way to "tune" the unit, replacing the OCXO is not a good idea. Also you may have to buy (and run long term ADEV tests on) a dozen MV89's before you get a "good" one. 

If you want to check the *stability* of the GSPDO, get a cheap Rb. That's the *only* way to know what's going on. There is no display / measurement / technique that will answer the question looking at the GPSDO alone. 

Bob

On Sep 18, 2013, at 10:11 AM, quartz55 <quartz55 at hughes.net> wrote:

> Moved antenna to fence line on a 10' emt.  Nothing much seems to change no matter what I do, so I guess this is what I'm locked into unless I start getting carried away.  I still get generally about a 400 ppt swing with the OSC, about 20 ns swing with the PPS and the other things are just what they are. Different filters and surveys don't seem to change anything that I've seen.  I like the antenna better at the fence. but I had to add another 30' of RG-6.  I have about 100' of FSJ4-50B that I have no use for right now, but I doubt that will do anything for me.  http://i251.photobucket.com/albums/gg287/DogTi/time/20139-181346_zps31fb89be.jpg
> 
> Is this acceptable?  From what I deduce, I can expect to get accuracy of +-0.2 Hz at 1GHz?  I was hoping for another decimal.  This should be plenty good to get mHz accuracy at 100 MHz if I can even measure that using SpecLab.  Seems to me Arthur was getting much smaller swings on his ppt with his older Nortel.
> 
> I did figure out the temp thing and found a link where it's explained, but I have a new chip coming and expect to change it, but I doubt if anything will change except the reported temp will most likely track to less than 1° C unlike it's doing now.
> 
> Would it be worth looking into the MV89A OCXO as a replacement to get better ppt?  I haven't done any looking into my OCXO yet to see what it's spec sheet may be.
> 
> Still waiting on a chip inductor that I messed up in the TS-2000 so I can get the XRef working.
> 
> Dave
> N3DT
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