[evlatests] [evla-sw-discuss] parameter simplification for the VHF receivers

[Barry Clark]

The only thing I see is that, in the future, we might want to specify
different delays for the two receivers.  Since this would involve
using the subband delay stuff, there is no code for it now, but
having two numbers might be handy in the non-immediate future.

Ken Sowinski wrote:
> Currently parmainator distinguishes between 75 MHz and 300 MHz for
> band related paramters.  The parameters of interest are subreflector
> rotation and focus and band-dependent delays.  Also there are T_cals,
> which are now obsolete in the paramters DB, and tables of attenuator
> settings, also obsolete.
> 
> I suggest that we have only one band code "VHF" to select the low
> frequency receivers.  Receiver.java will transform any reference
> to "75MHz" or "300MHz" to "VHF".  This allows us to keep only
> one set of parameters in the DB, rather than two identical sets;
> prevents possible mistakes when two sets are maintains; more
> accurately reflects the current hardware; and, eliminates the confusing
> necessity of having to know whether the script selected "75MHz" or
> "300MHz".
> 
> The rational is that there is one receiver box containing all
> receivers.  Its single output (dual polarization) is conneted
> to one T301 input.  Regardless of which band is selected, the
> hardware configuration is the same and the same wideband signal
> is presented to the T304.
> 
> Would doing this prevent anything that would be practical and useful
> with the current scheme?
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