[evlatests] Ant. 13, IFs BD: ~60d phase jumps every 20 seconds at C, X, L bands

[Jim Jackson]

This is curious. We noticed earlier this afternoon that the two L302's in 
Antenna 13 seem to have different firmware (or something else) in the 
MIB.  Even though both claim to be MIBVERSION 0.99 and MODULEVERSION 0.20, 
there are two missing monitor points on the L302-2 in antenna 13 and the 
L302-1 in Antenna 24  The monitor points are  M_LOCKH and C_LOCKH.

Pete and Matt - Are we sure these modules all have the same MIB and FPGA 
firmware?

Adding length to the LVDS heartbeat cable to these modules is a 
problem.  The project's worth of twinax cables were purchased from 
Tensolite as an expensive special order with custom connectors.  They are 
all the same length.  We could vary the length of the 128MHz coax cable 
feeding the clock to the FPGA.

Jim



At 09:54 AM 7/19/2006, Rick Perley wrote:
>     But why would this non-subtle behavior be absent before July 7th?
>And why only
>with antenna 13, IFs B and D?
>
>Barry Clark wrote:
>
> >This is almost certainly the heartbeat capture uncertaintly glitch we
> >saw in the lab.  I am happy that things are now working well enough in
> >the field that we notice it.  It could probably be cured by adding a foot
> >of cable to the LVDS heartbeat cable.  Only worth doing if this L302 is
> >in final form.
> >
> >I've lost track of what the revision state of this L302 is.  The vaunted
> >spreadsheets in techdocs contain no useful information for L302s.
> >
> >
> >
> >
> >>AR603 data taken between July 12th and July 15th show an odd behavior
> >>for ant. 13, IFs BD (AIPS IF 2 RR & LL): frequent ~60 degree phase jumps
> >>within a scan.
> >>
> >>
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