[time-nuts] Double oven ocxo's was Tbolt reception problems

[WarrenS]

John

Comparing Z3801 and Tbolts, although they do the same thing, Is hard, like apples and oranges.
Depending on what performance one is after, they both have strength and weaknesses.

One of the Z3801 biggest advantages is it Double Osc. The size and original cost of that one item is likely more and bigger than the whole Tbolt.
The more amazing thing is how the Tbolt can do as well as it does with it's simple, smaller and cheaper OXCO.
 And even here it is not all clear cut. The BEST Tbolts of a large run will outperform the worse (and maybe the average) Z3801.
But I have no doubt that the average Tbolt will come in second to the average Z3801 in many performance categories, mostly due to Z3801's DOCXO.

Now if I was tinkering with a 3801, Or any precision instrment for that matter, the first thing I do is come up with several modifications to make it even better, This really has little to do with the Tbolt, it is just because that is what I like to do. Given a Z3801, it would not take long to have a list of how to make it even better.

My personal opinion is when comparing unmodified GPSDO,  the average Z3801 is the better unit because of its double Oven expensive Osc and better Default settings
BUT,  That can all be changed or Fixed. My real turn on for the Tbolt is that I feel that its GPS engine is much better than the Z3801's GPS engine 
which is the real limit on how good the performance can be improved.
I'll bet that the ultimate modified Tbolt is going to be a lot better than a standard OR modified Z3801.


ws

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[time-nuts] Double oven ocxo's was Tbolt reception problems
John Green wpxs472 at gmail.com 

Warren,
Perhaps I am being too hard on the Tbolt. If I never had a Z3801, I am sure
I would like the Tbolt a lot more. The Z3801 seems to just sit there and
work without having to assure either its voltage or temperature or anything
else for that matter. I do believe the things I am seeing are coming from
the Tbolt because I compared an LPRO to the Z3801 and saw only a very slow,
uniform slip in phase.  No jumping around at all. By slow, I mean that it
took several hours for it to slip 1 cycle.
As to the double oven OCXO, I have 2 I purchased off eBay in the last few
months. One is a Morion MV89 and the other a UCT 8663. I compared both to
the Z3801 over several days and was not impressed. They seemed no better
than a good single oven unit. Of course, I wasn't trying them over a large
temperature excursion but I expected them to be better than a single oven. I
wouldn't expect either of them to improve the Tbolt much. The only thing to
really impress me lately has been the LPROs. They do move but seem a lot
less picky about everything than a quartz oscillator.