[evlatests] ea08 synthesizer mystery

[Rick Perley]

    I am running tuning tests in preparation for the upcoming flux 
density observation in Jan.  I find that antenna 8, if IF#1 gave no 
fringes on IF1, but gave nice fringes on IF2 -- at S-band.  This was a 
few minutes ago...



Rob Long wrote:
> It would have been interesting to turn on the prescaler and look at the 
> frequency the L302s thought they were locked at(while you were having 
> problems).  Due to the comb generator problems we have seen, L302s will 
> sometimes lock to the spur vs the actual comb line.  This makes the 
> hardware appear to be working, but it is in fact off frequency.  We have 
> had intermittent lock loss problems on ea08 so we will check out the 
> L300 when we get a chance.
>
> Rob
>
> Ken Sowinski wrote:
>   
>> While trying to do an L band Widar observation ea08 was incoherent.
>> Checking the usual antenna things, including synthesizers, found
>> nothing wrong.  Eventually we went back to the old correlator
>> and found that ea08 incoherent in AC, but fine in BD.  Both the
>> L301 and L302 claimed to be working and locked.  both were rebooted,
>> but still no fringes.  I then started going through the bands and
>> ea08 worked fine at C, S, X, and K bands.  Back to L band and all
>> was working again.
>>
>> Will anyone hazard a guess as to what is happening?  Or, what to
>> try if this should happen again.
>>
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>
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