These are some plots are from a trial run where I tried to measure the location of the 3rd zero crossing of the 7499M signal as precisly as I could.
In order to know what I measure, I used my HP5061A Cesium frequency standard as timebase, it has a frequency offset in the 2e12 range and I was very interested in seeing if I could confirm this with the LORANC signal.
This is the time series, the downward slope corresponds to appros 1.6e12 so that is within the possible. The noise is wors than I hoped for, but considering that there is no filtering apart from the GRI integration and master code correlation I think it is actually a pretty good result. 

This shows the modified Allan variance and there are no nasty surprises there. 

And a FFT over the data shows no particular artifacts either. 